JP2000238927A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording device which has faster printing speed than a conventional device and which has no possibility of forming a smudge caused by rubbing of undried ink with a conveying roller even when using ink of slow drying speed. SOLUTION: A printing control device 12 controls printing with correcting dots which compose a character to be thinned according to a level of printing quality in the case of a character of 16 points or more. A roller member which composes each of a first conveying roller pair 14 and a second conveying roller pair 16 for sending a sheet of dried recording paper 32 outwards is provided in a region where thermal energy density is 80% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus adapted for high-speed printing.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 8-228481 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,
By heating the recording paper using both the radiant heat of the heating element and the warm air, the thermal energy of the heating element is effectively used, and the ink on the recording paper is fixed uniformly in a short time.

Japanese Patent Laid-Open Publication No. Hei 3-203648 discloses that a recording medium is conveyed to accurately convey a recording medium before printing and maintain an appropriate distance between a recording head and the recording medium. The transport roller for regulating the surface is formed of a material obtained by mixing chloropropylene rubber (hardness 50-70 / A scale) with a single fiber of nylon resin in a ratio of 5 to 10% (weight ratio), and is provided so as to be able to press against the transport roller. In addition, there is disclosed an ink jet recording apparatus in which a paper pressing member for pressing a recording medium against a conveyance roller is made of polyacetal or fluororesin.

In Japanese Patent Application Laid-Open No. Hei 3-203648, when such a material is used, when a recording medium is present between the transport roller and the paper pressing member, friction generated between the transport roller and the recording medium increases. Further, friction generated between the paper pressing member and the recording medium is relatively small. Further, when there is no recording medium between the transport roller and the paper pressing member, the friction generated between the transport roller and the paper pressing member becomes small.

Thus, the recording medium can be conveyed by the rotation of the conveying roller with a large conveying force, and the resistance of the paper pressing member at that time is small. The transfer can be performed.

Japanese Unexamined Patent Publication (Kokai) No. 3-251475 discloses a rotating outer ring, a ring spring for guiding the rotation of the outer ring and holding the entirety, and a lock piece for preventing the ring spring from falling. There is disclosed a paper press roll which has an integral structure with respect to the slide in the axial direction and employs polyacetal as the material of the outer ring.

[0007] This paper press roll does not use adhesive or welding for assembly, so simplicity of assemblability can be measured, strength can be obtained due to the integrated structure in the sliding direction, and the outer ring is made of polyacetal. Thereby, transfer of printing can be prevented.

Further, Japanese Patent Application Laid-Open No. Hei 10-139235 discloses a discharge mechanism of a recording apparatus for discharging a sheet by bringing a feed roller into contact with the sheet. A structure in which a discharge roller composed of a ring-shaped support portion provided on the shaft and an elastic portion integrally forming the outer peripheral portion and the support portion is provided, the number of parts is reduced, and a simple structure is provided. Which realizes downsizing of the apparatus.

Japanese Patent Application Laid-Open No. 5-104802 discloses a structure in which when a guide member is moved in accordance with the width of a recording sheet, a discharge means moves with the movement of the guide member. There has been proposed a recording sheet in which the vicinity of an end portion in the width direction of a recording sheet is always pressed by a discharging unit by movement. As a result, since rollers and spurs for always discharging the paper are arranged outside the recording area of the recording sheet, there is no danger that undried ink adheres when discharging the recorded sheet, and thus the recording is performed. It is possible to eliminate the possibility that the sheet becomes dirty.

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. Therefore, it is conceivable to use a heat source of high thermal energy so that the ink dries reliably. In general, when such a heat source of high thermal energy is used, air is allowed to flow over the recording paper not only to achieve more reliable drying but also to prevent the recording paper from burning.

[0011]

In recent years, the demand for high-speed printing has been increasing, and the printing speed has been increased. Therefore, it has become a major problem to dry the ink efficiently corresponding to the printing speed.

In particular, it is difficult to dry the ink efficiently with an ink jet recording apparatus that performs high-speed printing using slow-dry ink. For this reason, the transport roller that discharges the recording medium with ink attached to the outside and the undried print portion rub against each other, and smudges occur when the transport roller drags the ink in the undried portion.

As a means for solving such a problem, for example, a recording medium on which ink has been adhered using a heating element such as a halogen lamp, which generates high thermal energy so as to completely eliminate an undried print portion, is used. Drying is conceivable.

[0014] The halogen lamp has an energy density distribution characteristic in the lengthwise direction that becomes higher as the distance from the electrode to a certain distance from the electrode increases, and becomes substantially constant when the distance from the electrode exceeds a certain distance.

For this reason, when a halogen lamp is used as a heating element, the drying property near the both ends of the recording paper is deteriorated due to its energy density distribution characteristics. In order to prevent this, the amount of heat of the heating element is increased so that the energy density near both ends of the recording paper is large enough to dry.
There is a problem that the temperature in the central region becomes too high, and the recording paper is burnt or, in the worst case, the recording paper burns.

It is also conceivable to adopt a configuration in which a region near the electrode is not used as a dry region but a central region having an almost constant energy density is used as a dry region. However, there is another problem that the apparatus becomes large.

The apparatus disclosed in Japanese Patent Application Laid-Open No. H08-224871 has good drying properties in normal printing, but has a considerable problem when printing at a high speed of 12 to 16 sheets per minute as an ink jet printer. Since a drying time is required, it cannot be dried sufficiently. If the configuration disclosed in JP-A-8-224871 is adjusted to increase the thermal energy of the heating element in order to dry it sufficiently, another problem such as firing of the paper in the apparatus occurs, and the safety is increased. There is a problem that it is difficult to achieve both the drying property and the drying property.

Japanese Patent Application Laid-Open No. 3-251475 discloses that a paper holding roll is made of polyacetal,
Although the one that prevents the transfer of ink is disclosed, there is a problem that if the undried ink remains on the paper, some transfer cannot be avoided, and the transfer of the ink cannot be completely prevented. . In particular, there is a drawback that smudge which easily occurs when using pigment ink cannot be prevented.

Further, Japanese Patent Laid-Open No. 5-104802 discloses a configuration in which a roller is disposed outside a recording area to avoid contact between the roller and undried ink. However, the roller is disposed outside the recording area. This causes a problem that the size of the printable paper is limited. In addition, if the recording area is widened, the area where the roller and the paper engage is narrowed, so that a sufficient conveyance force cannot be secured, and in the worst case, there is a problem that a conveyance failure is caused.

From the above, according to the present invention, the printing speed is higher than before, and even when using slow-dry ink, the undried ink rubs against the transport roller to form smudge on the recording paper. It is an object of the present invention to provide an ink jet recording apparatus that does not have a possibility of performing the operation.

[0021]

According to a first aspect of the present invention, there is provided an ink jet recording apparatus for applying thermal energy to a recording medium on which ink has been conveyed along a predetermined conveying path. Installed after the heating element,
A transport roller pair that transports the ink-attached recording medium by rotating the ink-attached recording medium in a fixed direction while sandwiching the ink-attached recording medium; The transport roller disposed on the attachment surface side has a smooth surface and is made of a material having high hardness.

That is, according to the first aspect of the present invention, the transport roller formed of a material having a smooth surface and a high hardness is disposed on the ink-adhered surface side of the recording medium on which the ink is applied, so that the transport roller and the undried By preventing the printed portion from rubbing with each other, the ink jet recording apparatus is less likely to cause smudge even when the ink is not dried.

Preferably, as set forth in claim 2, the transport roller disposed at least on the ink-adhered surface side of the ink-adhered recording medium has an average surface roughness Ra of 0 to 1.0 μm, and It is made of a material having a Young's modulus of 1 × 10 ⁸ Pa or more and 2.5 × 10 ¹¹ Pa or less. As a result, the surface frictional force can be suppressed to a small value, so that an ink jet recording apparatus in which the occurrence rate of smudge is remarkably reduced is obtained. The material constituting such a transport roller may be as set forth in claim 3
As described above, plastic such as acetal resin and metal such as aluminum alloy are preferable.

Further, in the invention of claim 4, according to claims 1 to
4. The ink jet recording apparatus according to claim 3, wherein the heating element has a heat energy density that gradually increases from each of both ends to a certain distance, and a heat energy density distribution at a position that is more than the certain distance. 5. Is a substantially columnar member provided so that the thermal energy density distribution is constant in the longitudinal direction, and the longitudinal direction thereof intersects the transport direction of the ink-attached recording medium. The pair is arranged in a dry area where the heat energy density given by the heating element is 80% or more.

That is, a heating element having a thermal energy density distribution in the longitudinal direction in which the thermal energy density gradually increases from each of both ends to a certain distance, and the thermal energy density distribution becomes constant at a position apart from the predetermined distance. Means that a given area of thermal energy is applied to the dry area in which the ink-attached recording medium is arranged, and that thermal energy is applied to the areas at both ends, the heat energy becoming weaker toward the ends. Therefore, since the dryness of the regions at both ends is worse than the dryness of the central region, even if the ink adhered to the central region is dried, the ink adhered to both end regions is not necessarily dried.

Therefore, in the present invention, the transport roller pair is disposed in a dry area where the thermal energy density given by the heating element is 80% or more, so that the ink deposition on the ink-laden recording medium is achieved. The possibility that the transport roller disposed on the surface side comes into contact with the undried ink is reduced, and thereby the occurrence rate of smudge is remarkably reduced.

If the thermal energy density is lower than 80%, the level of dirt adhering to the rollers tends to increase as shown in FIG. The heat energy density given from the body is set to be in the dry region where it is 80% or more.

FIG. 3 shows 4024 paper (XEROX).
Company: trade name) and Color Expression Bright White 93 paper (XEROX: trade name / hereinafter, referred to as CE paper), printed with the same type of ink, dried for about 2 seconds, and contacted the printed surface. This is a result of examining the ink stain level of a roller member for feeding 4024 paper or CE paper by changing the arrangement for each thermal energy density. As is clear from FIG. 3, when the heat energy density in a region where the heat energy density is constant is 100%, the heat energy density is 8%.
When the roller member is disposed in an area to which a heat energy density of less than 0% is applied, the contamination level of the roller member is large, but when the roller member is disposed in an area to which a heat energy density of 80% or more is applied, the roller member is disposed. Tends to be low. This is 4024 paper and C
Not only E paper, but also J paper (FSOS (Fuji Xerox Office Supply Co., Ltd.): trade name), Green 100
A similar tendency occurs when other types of recording media such as paper (FSOS: trade name) are used.

As for the stain level, 0 indicates no transfer of undried ink, 1 to 3 indicates slight transfer of undried ink, and 4 to 6 indicate transfer of undried ink completely. Represents that the transfer ratio increases each time.

That is, by arranging the transport roller in a region where the thermal energy density is 80% or more, it is possible to avoid rubbing of the undried ink and the transport roller, thereby preventing the generation of smudge.

According to the fifth aspect of the present invention, the conveying roller disposed on the surface opposite to the ink adhering surface side of the ink-adhered recording medium is made of rubber, so that the ink adhering as a conveying roller pair is formed. As a result, the friction between the transport roller disposed on the opposite surface and the ink-attached recording medium is increased, and the ink-attached recording medium is reliably slid without slipping. It can be sent out.

According to a sixth aspect of the present invention, an ink is ejected from a head at a timing based on input image data, and the recording medium is conveyed along a predetermined conveyance path according to the input image data. Type of ink used, type of recording medium to be used, ink absorptivity for the recording medium, input image A print control unit that adjusts an adhesion ratio of ink to be adhered to a recording medium so that at least one of the data is a parameter and the paper stain is equal to or less than a predetermined limit.

The dryness of the ink depends on the amount of ink to be attached to the paper, the type of ink used, the type of paper used,
It depends on the absorption between the ink used and the paper.

Therefore, in the invention according to claim 6, the print control unit determines the type of ink to be used, the type of recording medium to be used, the absorption rate of ink to the recording medium, Selecting at least one of the input image data as a parameter, adjusting an adhesion rate of ink to be attached to the recording medium based on the parameter,
The amount of ink adhered to the paper is reduced so that the paper stain is less than a predetermined limit.

That is, some types of ink are hardly absorbed by the recording medium, and others are easily absorbed. When the “type of ink to be used” is selected as a parameter, the print control unit determines whether the ink to be used is It is determined whether the ink is hardly absorbed by the recording medium or the ink is easily absorbed by the recording medium. If the ink is hardly absorbed by the recording medium, the ink adhesion rate is adjusted to be low.

In the case where the ink to be used is easily absorbed by the recording medium, printing may be performed without adjusting the ink adhesion ratio, or the ink adhesion ratio may be adjusted to be low. Furthermore, the selection of whether or not to adjust the ink adhesion rate when the ink to be used is likely to be absorbed by the recording medium may be configured to be selected by the user by incorporating the setting into the overall inkjet recording apparatus.

Depending on the type of recording medium to be used, there are some types that hardly absorb ink and those types that easily absorb ink. When the “type of recording medium to be used” is selected as a parameter, the print control unit It is determined whether the recording medium to be absorbed hardly absorbs ink or the ink easily absorbs ink. If the recording medium is difficult to absorb ink, the ink adhesion rate is adjusted to be low.

When the recording medium to be used easily absorbs ink, printing may be performed without adjusting the ink adhesion ratio, or the ink adhesion ratio may be adjusted to be low. When the recording medium to be used easily absorbs the ink, the selection of the presence or absence of the adjustment of the ink adhesion rate may be incorporated in the setting of the entire inkjet recording apparatus and selected by the user.

Further, when the "absorption rate of ink to recording medium" obtained based on the type of recording medium to be used and the type of ink to be used is selected as a parameter, the print control unit determines that the absorption rate is a predetermined value. When the value is smaller than the predetermined value, the ink adhesion rate is lowered, and when the absorption rate is equal to or more than a predetermined value, the adjustment is performed so that the ink adhesion rate remains unchanged. In addition,
Also in this case, the user may determine whether to adjust the ink adhesion rate when the absorption rate is equal to or greater than a predetermined value.

The “input image data” includes at least one of a solid line area and a solid curve area.
There are image data representing line / character images including image data such as photographs and pictures having line / character image data and halftone data for each of a plurality of colors. The data also includes font size information indicating the size of the character.

That is, since the size of the solid-filled linear region and the solid-filled curved region can be determined based on the font size, the "font size" included in the input image data is selected as a parameter. If the font size is equal to or larger than a predetermined size, the print control unit adjusts the ink adhesion rate to be low, and if the font size is small, adjusts the printing so that it is printed as it is.

This makes it possible to suppress the amount of ink adhering to the recording medium for a large font that is difficult to dry, thereby improving the drying property.

When the information representing the size of the "image data representing a line image" is selected as a parameter, as in the case of selecting the "font size" described above, ink is applied according to the size of the line image. It is advisable to adjust the rate. Further, in image data representing a halftone,
It is preferable to adjust the ink adhesion rate based on the size of the solid-painted area, the color density, and the like.

In the above, the case of individually selecting and using parameters has been described. However, by selecting two or more of the above parameters and adjusting the ink adhesion rate, the drying property can be further improved. .

The adjustment of the ink adhesion rate by the print control unit can be relatively easily performed by partially thinning out the dots constituting the font or adjusting the dot size.

[0046]

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

This ink jet recording apparatus has the structure shown in FIG.
As shown in (a), the printing control device 12, the head unit 30, the head unit drive motor 18, the dryer unit 10, the first transport roller pair 14, the second transport roller pair 16, and the roller drive motor 17 are roughly classified. And

The head unit 30 includes Y (yellow),
It is composed of an ink tank (not shown) that stores four color inks of M (magenta), C (cyan) and B (black), and a recording head (not shown) provided for each color. Image data (hereinafter, referred to as color image data) corresponding to each color is input to the head unit 30.
These color image data are input to recording heads corresponding to respective colors in the head unit 30. The recording head ejects ink droplets toward the recording paper 32 at a timing based on the input color image data.

The head unit 30 is slidably provided on a guide 22 provided along the width direction of the recording paper 32, and is fixed to a part of the rotating belt 20. The rotation belt 20 is an annular belt provided along the width direction of the recording paper 32 and configured to rotate by the rotation force of the head unit drive motor 18. Therefore, the head unit 30 slides on the guide 22 with the rotation of the rotation belt 20 that rotates by the driving of the head unit drive motor 18, and moves in the width direction of the recording paper 32.

At the subsequent stage of the head unit 30, there is provided a dryer unit 10 in which a halogen lamp as a heating element is provided in a direction perpendicular to the conveying direction. The dryer unit 10 has a drying area formed in an area facing the halogen lamp, and dries the recording paper 32 having ink applied thereon, which passes through the drying area, from the side where the ink is applied.

At the subsequent stage of the dryer unit 10, a first transport roller pair 14 and a second transport roller pair 16 are arranged in parallel in order to discharge the dried recording paper 32 to the outside. Each of the first transport roller pair 14 and the second transport roller pair 16 has the same structure, and three roller members each having a substantially cylindrical shape are arranged in parallel on one rotation shaft to be integrated. As shown in FIG. 1B, the two rollers 14a, 14b and 16a, 16b are fixed in contact with each other so as to have a constant nip pressure. In FIG. 1B, for the sake of explanation, the first transport roller pair 1
4, only a part of the second conveying roller pair 16 is shown.
Has the same configuration.

Each roller 14a, 14b and 16a, 16
b, three substantially cylindrical roller members are arranged in a region where the thermal energy density applied to the drying region is 80% or more.

That is, as shown in FIG. 2, the halogen lamp used as a heating element is a cylindrical heating element that radiates heat energy between a pair of electrodes, and is located at a certain distance from both electrodes on both ends. Has a characteristic that the thermal energy density gradually increases, and the thermal energy density becomes constant over a certain distance.

Therefore, the calorific value of the halogen lamp to be used is determined so that the recording paper 32 disposed in the region where the thermal energy density is constant becomes sufficiently dry. For this reason, at both ends of the dry region corresponding to a certain distance from both electrode sides, the dryness tends to be insufficient. Therefore, in the present embodiment, the three substantially cylindrical roller members are arranged in a region where the thermal energy density is 80% or more, so that the roller contacts only a region where drying is sufficient.

Further, two rollers 14a, 14b and 1 fixed in contact with each other so as to have a constant nip pressure.
Although not particularly shown, the fixing mechanism of the recording papers 3a and 16b is, for example, an elastic member such as a spring.
The second roller 14b disposed on the back surface side (that is, the side where ink is not adhered) of the second roller 14 is fixed with a force applied to the first roller 14a disposed on the ink adhered surface side. Configuration. In the present embodiment, the nip pressure generated between the pair of rollers is adjusted to be approximately 20 gw / mm in terms of linear pressure.

The first rollers 14a and 16a disposed on the side of the recording paper 32 on which the ink is adhered have an average surface roughness Ra.
Is 10 μm or less and the acetal resin has a Young's modulus of 3.0 × 10 ⁹ Pa.

Here, FIG. 4 shows the result of verifying whether the amount of the undried ink changes depending on the material of the roller.
In FIG. 4, the horizontal axis represents the time (sec) during which the recording paper 32 was placed in the dry area, and the vertical axis represents the stain level. As is clear from FIG. 4, when the drying time is 6 seconds, the roller of EPDM (ethylene propylene rubber) has a slight transfer, but the roller of POM (polyoxymethylene) which is a kind of acetal resin. Shows that there is no transfer at all, and even if there is an undried area, it is difficult to adhere to the roller. This is presumably because friction between POM (polyoxymethylene), which is an acetal resin, and the ink-adhering surface of the recording paper 32 is reduced.

Therefore, the first rollers 14a and 16a disposed on the ink adhering surface side of the recording paper 32 should have an average surface roughness Ra of 10 μm or less and a Young's modulus of 3.0 × 10 ⁹ Pa.
, The friction between the recording paper 32 and the ink adhering surface of the recording paper 32 is reduced, and the first roller 14
The generation of smudge caused by the rubbing of the inks a and 16a with the undried ink on the ink-adhered surface of the recording paper 32 can be further suppressed.

The second rollers 14b and 16b disposed on the back side of the recording paper 32 are made of EPDM (ethylene propylene rubber) having a large friction with the recording paper 32. As a result, the occurrence of slippage between the recording paper 32 and the recording paper 32 during transportation is reduced, so that reliable transportation can be performed.

The second rollers 14b and 16b are rotated at a constant speed by the roller driving motor 17 in the direction A shown in FIG. The recording paper 32 is a second roller 1
The rollers 4b, 16b are wound between the first rollers 14a, 16a and the second rollers 14b, 16b by the rotation of the rollers 4b, 16b, and are transported along the transport direction shown in FIG. 1 by the rotation of the second rollers 14b, 16b. . The first roller 14 provided so as to contact the second rollers 14b and 16b with a constant pressure
1a and 16a are rotated in the direction B, which is the direction opposite to the direction A shown in FIG. 1, by the movement of the recording paper 32 wound between the second rollers 14b and 16b. With such a pair of first transport rollers 14 and a pair of second transport rollers 16, the recording paper 32 that has been dried by the dryer unit 10 is formed.
It will be accurately discharged to the outside of the ink jet recording apparatus.

The print control device 12 controls the rotation of the head unit drive motor 18 and interprets the drawing command of the application to arrange the dots having gradations.
(Raster data) and perform various correction processes.

The rotation of the head unit drive motor 18 is controlled such that the ink is ejected to a target position in synchronization with the ejection timing of the head unit 30 that ejects ink droplets in accordance with the input image data. The control of the forward / reverse rotation of the head unit drive motor 18 is carried out.

Further, the print control device 12 determines the print image quality level specified by the user and determines the print quality level of paper to be printed such as, for example, 4024 paper (plain copy paper), ink jet dedicated paper, or polyester OHP sheet. Various correction processes are performed on the developed various data based on the type.

One of various correction processes performed by the print control device 12 includes a process of adjusting the ink adhesion rate, which is a process corresponding to the present invention. This process of adjusting the ink adhesion ratio is a process of reducing the amount of ink adhering to the recording paper by thinning out the dots and improving the drying property. In the present embodiment, the thinning ratio is changed according to the print image quality level. Is set to

That is, the print control device 12 thins out the dots constituting the characters for all characters of a certain font size or more (here, for example, 16 points) according to a certain rule, and the thinning rate is also For example, when the print image quality level is the high image quality level, the number of dots of 10% of the total number of dots forming the character is thinned out, and when the print image quality level is the standard image quality level, 25% of the total number of dots forming the character is thinned out Is thinned out, and if the print image quality level is a low image quality level, adjustment is made so as to thin out the dot number of 50% of the total number of dots constituting the character.

It should be noted that the thinning rate described here is merely an example, and it goes without saying that the thinning rate can be changed according to various conditions such as the image quality level. Further, the font size is set to 16 points or more as a certain font size or more, but is not limited to 16 points. In general, characters up to about 16 points are generally used in printing a monochrome document. If the characters are up to about 16 points, the drying property is good to some extent. In this embodiment, it is set to 16 points because it may be too close to dry sufficiently.

Here, as an example, 10 mm × 10 mm (240 × 600 mm at 600 dpi)
240 pixels, equivalent to 34 pl) are printed without thinning out the dots that make up the solid patch, the dots that make up the solid patch by 50% are thinned, and 16
4024 papers, CE papers, J papers, and G papers when the dots constituting the character of the point are printed without thinning, and when the dots constituting the character are thinned out by 50%.
Stain levels were checked using each of the reen100 papers.

Note that “equivalent to 34 pl” means 600 dp
It represents the volume per ink drop in an ink jet printer having a resolution of i. The volume per ink drop varies in a certain range depending on the specifications of the ink jet printer, but is assumed to be 34 pl here.

The stain level was determined by using one and two halogen lamps as heating elements, and by setting the drying time to 2, 4, and 6 seconds. Was rolled with a rubber roll to check the dirt level of the rubber roll.
After applying a pressure of 0 g weight / 1 cm ² , the paper was examined in two ways: the result of examining the stain level of the paper. Table 1 shows the results.

[0070]

[Table 1]

From the results shown in Table 1, it can be seen that the drying property when thinning out by 50% is good.

The method of thinning out the dots is, for example, thinning out with a staggered mask (see FIG. 5D), thinning out with a staggered mask leaving the edge (see FIG. 5B), or 75%.
Various selections can be made, such as thinning out using a mask (see FIG. 5C).

FIG. 5A shows “A” printed with character image data in which the ink adhesion rate is not adjusted.
FIG. 5B shows “A” printed by character image data in which dots are thinned out by a staggered mask and the ink adhesion rate is adjusted by leaving the dots at the edge portion, and FIG. FIG. 5D shows “A” printed with character image data in which dots are thinned out using a staggered mask to adjust the ink adhesion ratio, and the character image data is printed with character image data in which the adhesion ratio is adjusted.

Note that the thinning rate can be set at least to such an extent that it can be recognized as a character, but this may be set by the user according to the purpose. For example, even if the density is low, the setting is such that the number of dots to be thinned out is increased as much as possible so as to dry at a high speed to reduce the amount of ink attached as a whole, or the setting is such that the number of dots to be thinned out is not increased so much that the density does not change much. And so on.

The determination of the presence or absence of thinning is not limited to the configuration using character information, but may be configured to use graphic vector data.

After performing such various correction processes, the print control device 12 outputs image data to the head unit 30, and the head unit 30 ejects ink droplets at a timing according to the image information.

Here, the process of adjusting the ink adhesion rate by the print control device 12 will be described with reference to the flowchart of FIG. Here, for the sake of simplicity, the adjustment processing of only character data will be described.

First, in step 100, the image data is set to 1 based on the font size data included in the image data.
It is determined whether the data represents characters of 6 points or more. If it is determined that the data represents characters of 16 points or more, the process proceeds to step 102 to determine whether the print image quality level set by the user is a low image quality level.

If it is determined in step 102 that the image quality is low, the flow advances to step 104 to reduce the number of dots constituting the character to 50% so that the shape of the character does not change.
After the thinning, the process proceeds to step 106. If it is determined in step 100 that the data is not data representing characters of 16 points or more, the process proceeds to step 106.

On the other hand, if it is determined in step 102 that the image quality is not low, the process proceeds to step 112,
It is determined whether the print image quality level set by the user is the standard image quality level. If it is determined in step 112 that the image quality is the standard image quality level, the process proceeds to step 114, where the number of dots constituting the character is reduced by 25%.
Shift to 06. If it is determined in step 112 that the image quality is not the standard image quality level, the image quality level is high. Therefore, the process proceeds to step 116, where the number of dots constituting the character is reduced by 10%, and then the process proceeds to step 106.

In step 106, the image data is binarized by a dither method, an error diffusion method, or the like.
8. Compress the binarized image data in step 8
In 10, the head unit 30
At the end of the routine.

Although the above description has been given of the configuration in which the adjustment of the ink adhesion rate is performed by thinning out the dots, the volume of ink as a whole is controlled by controlling the volume per ink drop (hereinafter, referred to as a drop amount). It is also possible to adopt a configuration that reduces drying and improves the drying property.

The adjustment process of the ink adhesion rate by the print controller 12 in this case will be described with reference to the flowchart of FIG. Here, for simplicity of explanation, the coverage adjustment processing of only character data will be described.

First, in step 200, the image data is set to 1 based on the font size data included in the image data.
It is determined whether the data represents characters of 6 points or more. If it is determined that the data represents characters of 16 points or more, the process proceeds to step 202 to determine whether the print image quality level set by the user is a low image quality level.

If it is determined in step 202 that the image quality is of a low image quality level, the flow shifts to step 204, where all the drop amounts constituting the character are set to the above-mentioned 34 pl, which corresponds to the volume per ink drop of an ink jet printer having a resolution of 600 dpi. After the adjustment to 17 pl corresponding to 50% of the above, the process proceeds to step 206. If it is determined in step 200 that the data is not data representing a character of 16 points or more, the process proceeds to step 206.

On the other hand, if it is determined in step 202 that the image quality is not low, the process proceeds to step 212,
It is determined whether the print image quality level set by the user is the standard image quality level. If it is determined in step 212 that the image quality is the standard image quality level, the flow shifts to step 214 to reduce all the drop amounts constituting the character to 75% of the above 34 pl.
After the adjustment to 25 pl, which corresponds to If it is determined in step 212 that the image quality is not the standard image quality level, the image quality level is high, so that the process proceeds to step 216 to adjust all drop amounts constituting the character to 30 pl corresponding to 90% of the above 34 pl. Move to step 206.

In step 206, the image data is binarized by a dither method, an error diffusion method, or the like.
8. Compress the binarized image data in step 8
In 10, the head unit 30
At the end of the routine.

As described above, in this embodiment, the number of dots constituting a character is reduced, or the amount of ink adhering to recording paper is reduced by adjusting the amount of all drops constituting a character, thereby improving the drying property. Has improved.

In this embodiment, the recording paper 32
Rollers 14a, 16 arranged on the ink-adhering surface side of
a is composed of an acetal resin, has an average surface roughness Ra of 10 μm or less and a Young's modulus of 3.0 × 10 ⁹ P
As long as the material is a, various materials such as plastic, metal and rubber can be used.

The embodiments described above are merely examples, and the present invention is not limited to only the numerical values and configurations described in the above embodiments.

[0091]

As described above, the ink jet printer has an effect that, at a higher speed than before, a sufficient drying property can be obtained even when printing, and an ink jet recording apparatus free from the possibility of forming smudges can be obtained. In particular, even if the ink used is a slow-dry ink such as a pigment ink, there is an effect that an ink jet recording apparatus having good drying properties can be obtained without generating smudge.

Further, there is an effect that an ink jet recording apparatus can be obtained without impairing the conveying force of the recording medium and without forming a smudge.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a graph showing a relationship between a halogen lamp length and a heat energy density of the halogen lamp for indicating an arrangement region of a roller member.

FIG. 3 is a graph showing a relationship between a heat energy density of a halogen lamp and a stain level of a roller member.

FIG. 4 is a graph showing a relationship between a drying time and a stain level depending on a difference in material constituting a roller member.

FIG. 5 (a) is “A” printed with character image data in which the ink adhesion rate is not adjusted, and FIGS. 5 (b) to (d) are character images in which dots are thinned out by various methods to adjust the ink adhesion rate. “A” printed by data.

FIG. 6 is a flowchart in the case where the print control apparatus adjusts the ink adhesion rate by thinning out dots constituting characters.

FIG. 7 is a flowchart in a case where the print control device adjusts an ink adhesion rate by changing a drop amount forming a character.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dryer unit 12 Printing control device 14a 1st roller 14b 2nd roller 14 1st conveyance roller pair 16 2nd conveyance roller pair 17 Roller drive motor 18 Head unit drive motor 20 Rotating belt 22 Guide 30 Head unit 32 Recording paper

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Jun Isozaki 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd.Ebina Office (72) Inventor Fumihiko Ogasawara 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. In-house (72) Inventor Yumiko Namba 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Office (72) Inventor Keisuke Yasuda 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Person Toshiki Yui 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture F-Xerox Co., Ltd. F-term (reference) 2C056 EA09 EC71 EC72 HA29 HA33 HA46 2C059 CC04 CC14 CC24 3F049 AA05 DA12 LA07 LB03

Claims (8)

[Claims] 1. A heating element for applying heat energy to an ink-attached recording medium conveyed along a predetermined conveyance path, which is provided at a subsequent stage, and rotates in a predetermined direction while holding the ink-attached recording medium therebetween. A transport roller pair that transports the ink-attached recording medium, wherein the transport roller disposed on the ink-adhered surface side of the ink-attached recording medium has a smooth surface, An inkjet recording device made of a material with high hardness. 2. The transport roller disposed on the ink adhering surface side has an average surface roughness Ra of 0 to 1.0 μm and a Young's modulus of 1 × 10 ⁸ Pa to 2.5 × 10 ¹¹ Pa.
2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is made of the following materials. 3. The ink jet recording apparatus according to claim 2, wherein the transport roller disposed on the ink adhering surface side is made of plastic or metal. 4. The heating element has a thermal energy density distribution in which the thermal energy density gradually increases from each of both ends to a predetermined distance, and the thermal energy density distribution becomes constant at a position apart from the predetermined distance by a length. Direction, and
A substantially columnar member provided so that a longitudinal direction thereof intersects a conveying direction of the ink-attached recording medium, and the conveying roller pair has a heat energy density given by the heating element of 80% or more. The inkjet recording apparatus according to any one of claims 1 to 3, wherein the inkjet recording apparatus is arranged in a dry area. 5. The ink jet printer according to claim 1, wherein the transport roller disposed on the surface opposite to the ink adhering surface of the ink-applied recording medium is made of rubber. Recording device. 6. Ink is ejected from a head at a timing based on input image data to cause ink droplets to adhere to a recording medium conveyed along a predetermined conveyance path in an arrangement corresponding to the input image data. An ink jet recording apparatus for applying heat energy to a recording medium on which ink has been applied to dry the recording medium, wherein at least one of input image data, type of ink to be used, type of recording medium to be used, and absorptivity of ink to the recording medium is set as a parameter. An ink jet recording apparatus including a print control unit that adjusts an adhesion ratio of ink to be adhered to a recording medium so that paper contamination is equal to or less than a predetermined limit. 7. The input image data includes a font size, and the print control unit adjusts the ink adhesion rate when the font size is equal to or larger than a predetermined size.
3. The ink jet recording apparatus according to claim 1. 8. The ink jet recording apparatus according to claim 6, wherein the print control unit adjusts the ink adhesion rate by partially thinning out dots constituting a font or adjusting the dot size. .