JP2003223066A - Method and device for forming image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for forming an image wherein the reproducibility of an image fixed on a paper sheet is improved, and failures such as character-omission and lack of a highlight part due to a defective fixation are prevented, and further, the surface layer of a recording medium is not recessed and damaged by removing debris from the surface of a heat roller. <P>SOLUTION: The image forming method employs an image forming device having an image applying process of applying an image to the recording medium and a thermal fixation process of thermally fixing the recording medium with the image applied, and for thermally fixing the image while loading the recording medium on a cylinder. The thermal fixation process has a heat generating body for heating the recording medium and a pressing part for pressing and heating the medium simultaneously. The heat generating body is arranged in a direction orthogonal to the advancing direction of the recording medium, and the length of the heat generating body is made greater than the maximum width of the recording material. The recording medium is made to pass through an area inside both ends of the heat generating body. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic apparatus or an ink jet apparatus, in which an image formed on a recording material such as a recording sheet or a printing plate made of paper, resin, etc. The present invention also relates to an image forming method and an image forming apparatus for uniformly fixing regardless of size, which enables stable fixing particularly in a short time and compact fixing having a long life.

[0002]

2. Description of the Related Art The heat-fixing technique is widely used in printers, facsimiles, plate-making machines and the like which use techniques such as electrophotography, ionography and ink-jet for externally adding an image to a recording material. For example, in an electrophotographic copying machine, a drum-shaped photoconductor is charged and exposed to form an electrostatic latent image, and the electrostatic latent image is developed with dry or wet toner, and transferred to a recording paper. An image is formed by performing heat fixing.

In ionography, an electrostatic latent image is formed like an image on a recording medium having a charge retention ability by using an ion radiation head, and the electrostatic latent image is developed with a dry or wet toner. After that, heat fixing is performed to form an image.

On the other hand, in the ink jet printer, it is usual that ink is ejected from the recording head onto the recording paper, and the ink is naturally dried to form an image, and fixing is not performed. However, with an inkjet using a wax ink, it is difficult for the ink to soak into the recording medium, and therefore heat fixing is performed to ensure image adhesion to the recording medium. Further, in recent years, due to the increase in the printing speed of the inkjet technology, it is necessary to accelerate the drying of ink, and measures are taken such as irradiating UV light after drawing with UV ink or accelerating the drying of the ink solvent by a heating device or the like. It became so. On the other hand, in order to satisfy the requirements of light resistance or hue, the colorant fine particles in the ink may be coated with a resin or the like. In that case, the same image fixing as that of an electrophotographic copying machine is required, and heat fixing is performed. Is preferably used. Further, in a system for making a printing plate used for printing other than the case of directly printing on a recording sheet as a recording medium such as a printer / facsimile as described above, a heat fixing technique is used for the purpose of improving printing durability. Is used.

The heat-fixing technique is widely used in printers, facsimiles, plate-making machines and the like which use techniques such as electrophotography and ink jet for externally adding an image to a recording material. For example, in an electrophotographic copying machine, a drum-shaped photoconductor is exposed to form an electrostatic latent image, the electrostatic latent image is toner-developed, transferred to a recording paper, and then heat-fixed. A copied image is formed. Further, in a printer using an inkjet or an electrostatic inkjet, a series of operations are completed by ejecting ink from a recording head onto recording paper, drying the ink, and then fixing the ink. Also the printer,
In addition to printing by facsimile and the like, heat fixing technology is used and is incorporated in a system for making a printing plate used for printing.

In the fixing by the lamp heater, it takes time until a stable output is supplied from the heating element after the voltage is applied, and it takes time until the output is stabilized. This effect mainly appears at the leading end of the recording material, and at the leading end, the fixing temperature is lowered at the time of fixing, resulting in poor fixing, resulting in deterioration of the obtained image quality. The reasons why the output is not stabilized include various reasons such as the time required for the lamp heater to rise, and the need to heat the environment around the lamp heater.

Therefore, conventionally, a heat roller having a heat source has been used in a heat fixing device to fix the resin on the recording material added from the outside. In that case, if the heating temperature is low, image defects such as missing characters and highlight highlights occur due to poor fixing on the recording material.On the other hand, when excessive fixing occurs, image defects, Deformation of the recording material was observed, and the device was prone to failure. Therefore, the heat roller has a control mechanism that keeps the surface temperature of the roller constant, and when the surface temperature falls below the specified temperature, the output of the heating element of the heat roller is increased. When the temperature rises further, the output of the heating element is reduced.

[0008]

However, even if the heat roller has such a control mechanism, it is difficult to make the fixing temperature uniform in the width direction (the direction perpendicular to the traveling direction of the recording material). Fixation was very difficult. The reason is that the heat roller usually has a heating element inside,
If the amount of heat generated by the heating element is constant at all points, there is no heat source outside the end of the heating element, and there is a medium that removes heat. . Moreover, it is conceivable that heat is easily radiated from the end even on the recording material to be heated and fixed. Therefore, the width of the recording material is sufficiently smaller than that of the heating element of the heat roller and no problem occurs when passing through the center of the heating element, but the width of the recording material is large and the end portion of the heating element of the heat roller is When passing through the vicinity of the heating element, the fixing temperature was lowered at a portion passing near the end of the heating element on the recording material, resulting in poor fixing.

For this reason, when printing or plate making is performed by using a technique such as an electrophotographic copying machine, ionography, an ink jet printer or the like, character defects or highlights may occur due to improper fixing at both ends of the recording material. In addition to the occurrence of image defects such as dropout and reduction in saturation, when plate making is performed, in addition to problems such as missing characters and highlight highlights, printing defects occur. Especially when fixing at high temperature for a short time,
This tendency becomes remarkable. Further, when the temperature of the entire heat roller is raised in order to eliminate defective fixing at both ends, the temperature at the central portion rises, causing image defects due to excessive fixing, deformation of the recording material, and device failure. The present invention solves the above-described problems, and makes it possible to uniformize the fixing temperature of a recording material when performing fixing at high speed, and to perform high-quality image formation stably in a simple, inexpensive and short time. To aim.

[0010]

In order to achieve the above object, the invention of an image forming method according to claim 1 is an image adding step of adding an image on a recording material, and the image-added recording object. What is claimed is: 1. An image forming method, wherein an image forming apparatus having a heat fixing step of performing heat fixing of a material is used to perform heat fixing in a state where the recording material is mounted on a cylinder, wherein In an image forming method having a heating element for applying heat and a pressurizing section for applying pressure simultaneously with heating, the heating element is provided in a direction perpendicular to the recording material traveling direction, and the length of the heating element is the maximum width of the recording material. The recording material is made longer than that of the heating element so that the recording material passes through the inner area from both ends of the heating element.

According to a second aspect of the present invention, there is provided a cylinder, a recording material mounting means for mounting a recording material on the cylinder, and a recording target mounted on the cylinder by the recording material mounting means. Image adding means for adding an image on the material,
An image forming apparatus comprising: a heat fixing unit that heats and fixes a recording material on which an image is applied by the image applying unit on the cylinder; In an image forming apparatus having a heating element for applying heating and a pressurizing section for applying pressure simultaneously with heating, the heating element is provided in a direction perpendicular to the recording material traveling direction, and the length of the heating element is set to the recording material passing path. It is characterized by making it longer than the maximum width of.

The present invention can have the following configurations. (1) In the image forming method, the heat generation amount of the heating element is increased at both ends. (2) In the above image forming apparatus, the heat fixing unit is a heat roller. (3) In the image forming apparatus, the heating element is provided in a direction perpendicular to the recording material traveling direction, the heating element length is made longer than the recording material width, and an area 1 cm or more inward from both ends of the heating element is provided. The recording material is characterized by passing therethrough. (4) In the image forming apparatus, the heat generation amount of the heating element is increased at both ends.

As described above, according to the present invention, the heating element is provided in a direction perpendicular to the recording material traveling direction, and the length of the heating element is made longer than the maximum width of the recording material so that the recording material generates heat. Since it passes through the inner area from both ends of the body, it is possible to obtain a clear and high-quality image by an inexpensive and simple means. The image forming method according to the present invention includes:
Any image forming method can be used as long as it is an image forming method for externally adding an image to a recording material such as electrophotography, ionography, ink jet, etc., and the above methods can be applied or suitably used in combination. You can

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 is an example in which the present invention is applied to an electrophotographic copying machine, and shows a sectional view of the electrophotographic copying machine. In the image forming apparatus 1 of the electrophotographic copying machine shown in FIG. 1, the platen 4 is arranged on the apparatus main body 2 as in the case of a general electrophotographic copying machine. The scanning device 3 reads an image of a document set on the platen 4 and applies an image pattern corresponding to the document image to the photoconductor drum 5 as an exposure pattern. An image forming mechanism using a general electrophotographic system is arranged around the photosensitive drum 5. That is, first, the surface of the photosensitive drum is uniformly charged by the charging corotron 6, and the pattern read from the original is scanned and exposed to form an electrostatic latent image. Next, the developing device 7
From the toner to attach the toner to the electrostatic latent image,
A toner image corresponding to the electrostatic latent image is formed. Here, the case of performing dry development is described, but the development method is not limited to this, and wet development may be used. The toner image formed on the photoconductor drum is transferred onto the recording material mounted on the cylinder 8 by applying a voltage between the photoconductor drum 5 and the cylinder 8 by a power source (not shown). Here, the recording material P is fed into the cylinder 8 from the paper feeding unit 15 in a sheet-like manner, but the feeding method is not limited to this, and for example, a paper feeding roll may be provided. After the transfer of the toner image, the toner and the like remaining on the upper surface of the photosensitive drum are removed by the cleaning device 9.

The cylinder is mounted with a heat insulating material.
As a material that can be used for the cylinder, for example, metals such as iron, stainless steel, copper, and aluminum, and combinations thereof are mainly used. Although the metal cylinder can be used alone, the energy required for fixing is suppressed by using a heat insulating material. Any heat insulating material may be used as long as it has a heat insulating effect, and specifically, inorganic fibers such as glass wool and rock wool, polystyrene, polycarbonate, polyester, polyethylene, Teflon (registered trademark), and polyvinyl alcohol.・ Polyacetal ・ Nitrocellulose ・ Nylon ・ Ethylcellulose ・ Epoxy resin ・ Alkyd resin ・ Melamine resin ・
Urea resin, ABS resin, acrylic resin, polyurethane
Neoprene, cellulose acetate, beech S, beech N.
Materials such as natural rubber, phenol resin, silicon resin, epoxy resin, silicone rubber, polycarbonate, polypropylene, neoprene, vinyl chloride resin, butyl rubber, and the like, and foam materials using these materials, or a plurality of these materials are used in combination.

The sheet conveying path 12 is provided just before the image transfer section.
An aligning device 13 for aligning the sheets is provided at the end of the sheet. That is, the sheet supplied from the sheet feed tray is aligned, and the sheet is sent toward the image transfer portion at a predetermined timing in accordance with the toner image formed on the photosensitive drum.

The sheet on which the toner image is transferred is conveyed to the fixing device 11 and enters the fixing section. The fixing unit is provided with a heat roller 21 that applies heat and pressure to the recording material. When the set temperature of the heat roller 21 is raised, the rubber material forming the heat roller 21 is deteriorated at an accelerating rate, and the monomer components and additives as the rubber material are eluted.
Sometimes'crying out 'may occur. In addition, when the heat roller 21 has a high temperature, the bearing of the roller may deteriorate. Therefore, the temperature of the heat roller 21 is preferably 30 ° C. to 250 ° C. in order to provide the fixing property,
More preferably, it is 60 ° C to 200 ° C. Further, although the heat roller 21 is used in this fixing step, any material can be applied as long as it can apply pressure simultaneously with heating. For example, a panel heater, a belt fixing device, etc. can also be used suitably. Further, it is also possible to appropriately provide a fixing means capable of applying heat or pressure. For example, the heating means may be increased and two or more heat rollers may be used.

As a result, the paper on which the toner image is transferred is pressed while being heated by the heat roller 21 of the fixing unit, so that the toner on the paper is pushed or permeated into the paper in a softened or melted state, Promotes fixability. Further, when the heat roller 21 is not in contact with the recording material, it is preferable to idle rotate the heat roller 21 by an appropriate means from the viewpoint of keeping the surface temperature of the roller constant.

As the central material of the heat roller 21, Si silicon rubber is usually used from the viewpoint of heat resistance, but a rubber roller of fluorine type or NBR type rubber may be used, or another material may be used. Absent. Further, from the viewpoints of protecting the heat roller surface and preventing offset of the image forming substance from the non-recording material, polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), It is preferable to coat with a thin film containing a polydimethylsiloxane resin and having a thickness of 1 μm to 2 mm (more preferably 20 μm to 1 mm). Here, the nip pressure of the heat roller 21 with respect to the recording medium is 0.05 MPa to 250 MPa, more preferably, in order to obtain sufficient fixability.
It is 0.1 MPa to 20 MPa.

The heat roller 21 has a structure in which the surface temperature is constant, and the output is controlled by the surface temperature obtained by a surface temperature detecting means (not shown) to keep the surface temperature constant. Although the output is controlled by the time for which the voltage is applied, the control method is not limited to this. For example, there is a means for modulating the voltage applied to the heating element, or these may be combined. In addition, although it has been described here that the surface temperature is detected and the temperature control is performed, the temperature may be controlled by adjusting the supply amount without temperature detection after calculating the supply amount of the required voltage in advance. Good.
After that, the copy paper on which the fixing process is performed is separated by the separation claw 17
Then, it is removed from the cylinder and discharged to the discharge tray 14. In order to supply a sheet toward the image transfer section of the main body 2 of the image forming apparatus 1, a paper feeding section 15 is provided below the main body 2 of the apparatus.
Is arranged, and the sheet is sent out by using the conveyance roller device 16. The size of the paper applied to this apparatus is A3, A4, A5, B4, B5, but this fixing technique is effective regardless of the paper size.
In addition to large sizes such as 2, B1, B2, A3w size,
It is also effective for postcards and envelope printing.

The above-mentioned image forming method can be applied to both dry toner development and wet toner development. However, when it is applied to wet development, in order to remove the solvent evaporated in the machine, the hermeticity in the machine is increased and the solvent is removed. A mechanism is provided. Solvent recovery method, for example, by sucking the air in the machine containing the solvent,
A mechanism for liquefying by cooling this is provided, but the solvent recovery method is not limited to this, and any method that can separate the solvent such as a method of adsorbing the solvent using a solvent adsorbent is applied. it can.

In the embodiment described above, the fixing method of the present invention is applied to the case where the electrophotography is applied as the image providing means. However, in addition to the electrophotographic system, printers and facsimiles using techniques such as ionography and ink jet are used. It can be applied to a plate making machine or the like. In particular,
Inkjet technology can be used regardless of the ink ejection method and ink type. For example, the ejection method is
It can be used for any of heat, piezo, electrostatic, and the like, and a method in which these are appropriately combined can also be used.

FIG. 2 is a view for explaining the length relationship between the heat roller 21 and the recording material P according to the present invention in the direction perpendicular to the traveling direction of the recording material P. 2A is a schematic sectional view of the fixing device 11, and FIG. 2B is a heat roller 2.
1A is a front sectional view, FIG. 2B is a sectional view taken along line AA in FIG. 2A, and FIG. 2C is a recording material P. In FIG. 2A, the fixing device 11 includes a heat roller 21. With the rotation of the cylinder 8 that fixes the recording material P on which the image is transferred, the recording material P is heated by the heat roller 21.
And the cylinder 8 and is heated and pressed by the heat roller 21 in the meantime.

Next, the structure of the heat roller 21 will be described with reference to FIG. The heat roller 21 is composed of a cylindrical roller 21a on the outside, a heating element 21b inside thereof, and a heating wire consisting of a heating element winding 20c inside the heating element 21b. The surface material of the heat roller 21a is usually Si rubber, but a rubber roller of fluorine-based rubber or NBR-based rubber may be used, or another material may be used. Also, from the viewpoint of protecting the heat roller surface and preventing offset of the image-forming substance from the non-recording body,
A resin sheet having sociability to the toner on the surface of the heat roller, such as polytetrafluoroethylene (PTF)
E), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polydimethylsiloxane resin containing 1 μm to 2 mm (more preferably 20 μm to 1)
It is preferable to coat with a thin film having a thickness of (mm).
Here, the nip pressure of the heat roller is 0.05 MPa to 250 MPa, more preferably 0.1 to 20 MPa in order to obtain sufficient fixability.

The heat roller 21 is constructed so that the surface temperature becomes constant by controlling the amount of heat generated by the heating element 21b. That is, the output is controlled by the surface temperature obtained by means for detecting the surface temperature (not shown) to keep the surface temperature constant. The output is controlled by the time for applying the voltage, but the control method is not limited to this, and there is also a means for modulating the voltage applied to the heating element 21b. In addition, although it has been described here that the surface temperature is detected and the temperature is controlled, the temperature may be controlled by calculating the supply amount of the required voltage in advance and then modulating the supply amount without detecting the temperature. Good.

The heating element 21b inside the heat roller 21 is
A length direction is provided at right angles to the traveling direction of the recording material,
The heating element is made longer than the maximum width L that can be printed by the electrophotographic copying machine. When the recording material passes through the electrophotographic copying machine, it passes through an area 1 cm inside from both ends of the heating element of the heat roller 21b.
In the case of the heat roller, the heat radiation from the end portion is great, and in consideration of the heat radiation from the end portion, the heat generation amount of the heating element is changed so that it becomes large near the end portion. Here, the heating element 2
The heat wire 21c by winding is used for 1b.
As shown in the enlarged view of Figure (c), the winding density of
It is made larger in the vicinity C2 of the end portion to compensate for heat loss due to heat dissipation. The heat generation profile of the heat generating element 21b is appropriately determined according to the structure of the fixing portion, but the heat generation amount at the end portion is preferably 103% to 250% of the heat generation amount at the central portion, and more preferably 105% to It is 200%. Although the heating wire has been described as an example of the heating element of the heat roller, the heating element is not limited to this.

[0027]

Embodiment 1 Next, the present invention is applied to the above-mentioned copying machine,
Heat fixing was performed using a heat roller (manufactured by Hitachi Metals, Ltd.). The fixing conditions were a heat roller surface temperature of 150 ° C., a recording material conveyance speed of 14 mm / sec, and an applied pressure (nip pressure) of 0.8 MPa to the recording material of the heat roller.

[0028]

[Table 1]

The image reproducibility of the recording material in the case of Example 1 will be verified based on Table 1 below. In Specific Example 1, the heating element of the heat roller is made longer than the recording material width (the direction perpendicular to the traveling direction) in the electrophotographic copying machine, and passes through an area 1 cm or more inside from both ends of the heating roller. I did it. Further, the amount of heat generated by the heating element of the heat roller is increased at the end. As a result, the distribution of the fixing temperature on the recording material was uniform, and a very good image reproduction was obtained. In addition to this, no trouble occurred on the device. In the specific example 2, the heat generation amount of the heat generation element of the heat roller is increased at the end portion, and the heat generation element of the heat roller is set to the recording material width (direction perpendicular to the traveling direction).
Nothing longer than. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device. In Specific Example 3, the heating element of the heat roller is made longer than the width of the recording material (the direction perpendicular to the traveling direction) in the electrophotographic copying machine, and 1 c from both ends of the heating element of the heat roller.
It was designed to pass through the area inside m or more. The heating value of the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device.

In Comparative Example 1, the heat generating element of the heat roller is made to have the same length as the recording material width (direction perpendicular to the traveling direction) in the present electrophotographic copying machine, and the area inside from both ends of the heat roller heating element is set. I tried to pass. Furthermore, the amount of heat generated by the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became non-uniform, and the fixing failure occurred near both ends, and there were missing characters and highlight highlights.

As described above, the heating element of the heat roller is made longer than the recording material width (direction perpendicular to the traveling direction),
By passing the area inside by 1 cm or more from both ends of the heat roller heating element, the fixing temperature in the width direction can be made uniform, and a printed matter excellent in image reproduction can be provided. Further, the fixing temperature can be made uniform by increasing the heat generation amount of the heat generating element of the heat roller at the end portion, and a printed matter excellent in image reproduction can be provided.

[0032]

Second Embodiment Next, FIG. 3 shows an example in which the present invention is applied to an ink jet printer. FIG. 3 shows a cross section of an image recording apparatus having an inkjet recording apparatus. At the bottom of the ink jet recording apparatus, a recording paper and a cassette 41 containing a recording material P which is a resin sheet are loaded. A conveyance roller pair 43 is provided on the downstream side in the recording material conveyance direction.
And a carriage 45 on which the recording head 451 is mounted. The recording head 451 is a share mode 500-channel piezo inkjet device (Xa
Xaar Jet500S manufactured by ar Co. was used, and an oil-based ink (manufactured by the same company) was used. The drawing resolution was 720 dpi, and the dot size was changed in 8 steps to control the gradation. The recording material is conveyed by the conveying roller 43 to the drawing drum 46.
The dust is removed prior to this.
The dust removal method is a method of adsorbing dust on the surface by the adhesive roller 44, but the method is not limited to this.
For example, it may be removed by an air flow. The recording material is then conveyed below the recording head, and drawing is performed. When the drawing is completed, the fixing operation is started, and the fixing mechanism according to the present invention described in FIG. 2 performs the fixing. After the fixing is completed, the recording material P on the drawing drum 46 is separated from the drawing drum 46 by a separation claw (not shown), and is discharged to the discharge tray 48 by the conveyance roller 47.

The solvent in the ink is vaporized by the drawing and fixing operations to fill the inside of the machine. Therefore, in the area surrounded by the broken line, the hermeticity is improved and a solvent recovery mechanism is provided to recover the vaporized solvent in the machine. The collecting method is to send the air inside the machine to the solvent collecting mechanism 49, cool it with a refrigerant to separate the solvent, and send the separated air back into the machine. The recording head 451 ejects ink while moving in the direction perpendicular to the paper surface by the carriage 45, and draws an image according to the image signal. At this time, an image with a constant width is drawn on the recording material P. That is, the recording material P
The recording material P is conveyed by one line by the pair of conveying rollers every time the movement drawing is completed, and the next line is drawn. Such operation is repeated. Here, the carriage (recording head) is moved during drawing in the sub-scanning direction, but the carriage may be fixed and the recording material may be conveyed in the direction perpendicular to the paper surface.

Although the method of directly drawing and fixing the image on the recording material has been described above, the image forming method is not limited to this, and the image can be formed on the drawing drum by using the transfer drum as shown in FIG. The image may be transferred to the recording material. The recording material may be supplied by means other than the cassette, for example, by a roll. FIG. 4 shows a cross section of an image recording apparatus including a transfer drum. A drawing drum 56 as an image bearing member is formed of metal, plastic, glass, ceramics or the like, and may have an elastic layer in order to improve the adhesion to the recording material P. The recording head 551 of the carriage 55 has an inkjet recording device, which forms an image on the surface layer of the drawing drum 56. At this time, when the image is formed on the surface layer of the drawing drum 56, the transfer drum 52 is retracted so as not to contact the drawing drum 56. After forming the image on the drawing drum 56, the transfer drum 52 is brought close to the drawing drum 56 and brought into contact with the drawing drum 56 at a predetermined pressure. Then, the recording material P is taken out from the cassette 51, and is sandwiched between the drawing drum 56 and the transfer drum 52, so that the recording material P is brought into contact with the drawing drum 56 to perform the transfer (FIG. 4 shows this state. Is shown).
When the image is formed on the surface of the drawing drum 56, the surface temperature of the drawing drum 56 is heated in the range of 30 ° C. to 40 ° C. Therefore, when the drawing drum 56 and the recording material P are brought into contact with each other, heat is generated. Is applied, the image on the surface of the drawing drum 56 is transferred to the recording material P, and the image transferred to the recording material P is surely combined with the contact pressure between the drawing drum 56 and the recording material P. Retained. When the transfer is completed, fixing by the heat roller 21 is performed. By fixing the image transferred onto the recording material P by the fixing mechanism according to the present invention described in FIG. 2, the image holding force of the recording material P is further increased. After that, the recording material on the drawing drum is separated from the transfer drum 52 by a separation claw (not shown), and is discharged to the discharge side by the conveyance roller 57.

According to the present invention, heat fixing was performed using a heat roller (manufactured by Hitachi Metals, Ltd.). The fixing conditions are a heat roller temperature of 155 ° C. and a recording material conveying speed of 13 mm / s.
ec, the applied pressure (nip pressure) of the heat roller 21 to the recording material is 0.3 MPa.

[0036]

[Table 2]

The image reproducibility of the recording material in the case of Example 2 will be verified based on Table 2 below. In Specific Example 4, the heating element of the heat roller is made longer than the width of the recording material (the direction perpendicular to the traveling direction) in the present electrophotographic copying machine, and passes through an area 1 cm or more inside from both ends of the heating element. I did it. Further, the amount of heat generated by the heating element of the heat roller is increased at the end. As a result, the distribution of the fixing temperature on the recording material was uniform, and a very good image reproduction was obtained. In addition to this, no trouble occurred on the device. In Specific Example 5, the heat generation amount of the heat generation element of the heat roller is increased at the end portion, and the heat generation element of the heat roller is set to the recording material width (direction perpendicular to the traveling direction).
Nothing longer than. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device. In Specific Example 6, the heating element of the heat roller is made longer than the width of the recording material (the direction perpendicular to the traveling direction) in the electrophotographic copying machine, and 1 c from both ends of the heating roller.
It was designed to pass through the area inside m or more. The heating value of the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device.

In Comparative Example 2, the heating element of the heat roller was made to have the same length as the recording material width (direction perpendicular to the traveling direction) in this electrophotographic copying machine, and the area inside from both ends of the heating roller heating element was set. I tried to pass. Furthermore, the amount of heat generated by the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became non-uniform, and the fixing failure occurred near both ends, and there were missing characters and highlight highlights.

As described above, the heating element of the heat roller is made longer than the width of the recording material (direction perpendicular to the traveling direction),
By passing the area inside by 1 cm or more from both ends of the heat roller heating element, the fixing temperature in the width direction can be made uniform, and a printed matter excellent in image reproduction can be provided. Further, the fixing temperature can be made uniform by increasing the heat generation amount of the heat generating element of the heat roller at the end portion, and a printed matter excellent in image reproduction can be provided.

[0040]

Third Embodiment Next, a piezo type ink jet device (Ep
Drawing was carried out on the plate material using the Colorio PM750C manufactured by Son, Inc. and the oil-based ink manufactured by Xaar. As the plate material, a paper plate material provided with a hydrophilic image receiving layer shown below was used.

In the paper plate material, a water resistant layer containing polyvinyl alcohol, SBR latex, kaolin, and melamine resin as main components was provided on both sides of woodfree paper (100 g / m ² ). Further, an image-receiving layer was provided on the support so that the coating amount after drying of the dispersion liquid prepared as described below was 5 g / m ² , to prepare a paper plate material.

[0042] ・ Dispersion A   Gelatin (Wako Pure Chemicals first grade) 2g   Colloidal silica (Nissan Chemical; Snowtex C, 20% aqueous solution) 13g   Silica gel (Miyashi Silysia Chemical: Sylysia # 310) 5g   Hardener 0.3g   67 g of distilled water   Preparation method Add glass beads and disperse with a paint shaker for 10 minutes.

The piezo type ink jet device head described above was mounted on a plate making machine having the structure shown in FIG. 5, and the gap was adjusted to 1.5 mm. In the plate making machine of FIG. 5, 61 is a plate cylinder on which a printing plate 69 is mounted. As the printing plate 69, a paper plate is used here. 62 is an ink roller, 6
Reference numeral 3 is a dampening water roller, which applies oil ink and dampening water to the plate cylinder 6 respectively.
1 is supplied to the printing plate 69. A fixing device 11 according to the present invention is composed of a heat roller 21 shown in FIG. 6
A recording head 4 discharges a dedicated oil-based ink imagewise from the drawing head. Reference numeral 65 denotes a cleaning device for removing dust on the blanket cylinder, which is composed of, for example, an adhesive roller. 67
Is a blanket cylinder, and 68 is an impression cylinder. Recording head 64
A printing plate 69 drawn with a dedicated oil-based ink was made through the fixing device 11 as described later, and then printed on the machine.

Image data is transmitted to the arithmetic and control unit, the plate cylinder 61 is rotated by using 32 channels, the recording head 64 is moved, and ink is drawn on the paper plate 69 loaded on the plate cylinder 61. Let (Drawing resolution 720 dpi) Further, according to the present invention, the image was solidified by heating by fixing the heat roller 21 (manufactured by Hitachi Metals, Ltd.) to prepare a printing plate. The fixing conditions were a heat roller temperature of 160 ° C., a recording material conveying speed of 15 mm / sec, and an applied pressure (nip pressure) of 0.6 MPa to the recording material of the heat roller.
Subsequently, the obtained printing plate 69 is supplied with dampening water with a dampening roller 63 and printing ink with an ink roller 62,
The above printing ink image is transferred onto the blanket cylinder 67 rotating with the plate cylinder 61, and the printing ink image on the blanket cylinder is printed on the printing coated paper P passing between the blanket cylinder 67 and the impression cylinder 68. Was transferred and printing was performed.

[0045]

[Table 3]

The image reproducibility of the recording material in the case of Example 3 will be verified based on Table 3 below. In Specific Example 7, the heating element of the heat roller is made longer than the width of the recording material (direction perpendicular to the traveling direction) in the electrophotographic copying machine, and passes through an area 1 cm or more inside from both ends of the heating roller. I did it. Further, the amount of heat generated by the heating element of the heat roller is increased at the end. As a result, the distribution of the fixing temperature on the recording material was uniform, and a very good image reproduction was obtained. In addition to this, no trouble occurred on the device. In Example 8, the heat generation amount of the heat generation element of the heat roller is increased at the end portion, and the heat generation element of the heat roller is set to the recording material width (direction perpendicular to the traveling direction).
Nothing longer than. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device. In Specific Example 9, the heating element of the heat roller is made longer than the recording material width (the direction perpendicular to the traveling direction) in the present electrophotographic copying machine, and 1 c from both ends of the heating roller heating element.
It was designed to pass through the area inside m or more. The heating value of the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device.

In Comparative Example 3, the heating element of the heat roller was made to have the same length as the width of the recording material (direction perpendicular to the traveling direction) in the electrophotographic copying machine, and the area inside from both ends of the heating element was set. I tried to pass. Furthermore, the amount of heat generated by the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became non-uniform, and the fixing failure occurred near both ends, and there were missing characters and highlight highlights.

As described above, the heating element of the heat roller is made longer than the width of the recording material (direction perpendicular to the traveling direction),
By passing the area inside by 1 cm or more from both ends of the heat roller heating element, the fixing temperature in the width direction can be made uniform, and a printed matter excellent in image reproduction can be provided. Further, the fixing temperature can be made uniform by increasing the heat generation amount of the heat generating element of the heat roller at the end portion, and a printed matter excellent in image reproduction can be provided.

[0049]

Fourth Embodiment FIG. 6 shows a toner jet recording apparatus provided with a fixing device according to the present invention. In FIG. 6, the toner jet recording device 650 includes a recording unit 651 and the thermal fixing unit 11 according to the present invention. The toner jet recording device 650 is provided with a paper feed cassette 631 for loading the recording paper P and a paper ejection tray 638 for taking out the recording paper P. In the recording unit 651, an image is recorded on the paper P that is inserted from the paper feed cassette 631 and is conveyed by the pair of conveyance rollers 632. Then, the paper P is placed on the drawing drum 659.
In the heat fixing section 11 with the paper loaded, the paper P
The image recorded on is fixed. Further, the sheet P is sent to the take-out port 638 via the pair of conveying rollers 637.

The recording portion 651 includes a rotatable brush roller 652 having a brush for charging the toner T, an aperture electrode 653, and an opposing electrode provided to face the aperture electrode 653 at a predetermined interval. It is composed of a drawing drum 659 having a function. The drawing drum 659 is connected to the power source E2 (minus). The heat fixing unit 11 is equipped with a heat roller 21, the paper P is mounted on a drawing drum, and when drawing is completed, it passes under the heat roller 21 and is arranged so that it can be fixed.

Around the brush roller 652, the toner T is rotatable according to the rotation direction of the brush roller 652.
Roller 65 for supplying the toner to the brush roller 652
4 and the toner T attached to the brush of the brush roller 652.
And a scraping member 655 for repelling the brush are provided in contact with the brush roller 652, respectively. In addition, the supply roller 65
4, a supply blade 656 for supplying the toner T to the supply roller 654 with a uniform thickness is provided in contact. The toner T is stored on the supply blade 656. Supply roller 654 and supply blade 656
Are covered by a case K. The aperture electrode 653 is provided above the brush roller 652.

When a well-known image forming signal and image data are input from an external device (not shown), the insertion cassette 631
The sheet P inserted from is conveyed to the recording unit 651 by the feed roller 632. In the recording unit 651, the toner T is pressed against the supply roller 654 by the supply blade 656 and carried on the surface of the supply roller 654. The toner T is supplied to the brush roller 652 by the rotation of the supply roller 654. At this time, the toner T is, for example, positively (+) charged by friction with the brush while being in contact with the supply roller 654 and the brush roller 652.
The toner T charged positively (+) is transferred to the brush roller 65.
2 is supported.

In the vicinity of the aperture electrode 653, the scraping member 655 scrapes the brush of the brush roller 652 as the brush roller 652 rotates. Then, when the brush returns to its original position due to elasticity, the toner T carried by the brush in an appropriate amount jumps up and is supplied in the form of a cloud to the aperture electrode 653. At this time, the voltage applied from the signal source S to each control electrode layer of the aperture electrode 653 is controlled according to the input image signal, and the flow of the toner T is modulated. The modulated and positively (+) charged toner T is attracted to the negative (-) power source E2 connected to the counter electrode and flies toward the counter electrode. Then, the toner T is attracted to the paper P mounted on the drawing drum 659. After that, the paper P on which the toner T is attached is conveyed to the thermal fixing unit 11 while being mounted on the drawing drum 659. Then, the paper P on which the fixing is completed is conveyed by the conveying roller 63.
The sheet is conveyed to the sheet discharge tray 638 via 7 and discharged. The image was fixed by heat fixing of the heat roller according to the present invention described in FIG. The fixing conditions are a heat roller temperature of 170 ° C., a recording material conveying speed of 10 mm / sec, and a pressure (nip pressure) applied to the recording material by the heat roller 21.
It was 0 MPa.

[0054]

[Table 4]

The image reproducibility of the recording material in the case of Example 4 is verified based on Table 4 below. In Specific Example 10, the heating element of the heat roller is made longer than the recording material width (direction perpendicular to the traveling direction) in the electrophotographic copying machine, and passes through an area 1 cm or more inside from both ends of the heating roller. I did it. Further, the amount of heat generated by the heating element of the heat roller is increased at the end. As a result, the distribution of the fixing temperature on the recording material was uniform, and a very good image reproduction was obtained. Besides this,
No troubles occurred on the device. In Example 11,
The heat generation amount of the heat generating element of the heat roller was increased at the end portion, and the heat generating element of the heat roller was not made longer than the width of the recording material (direction perpendicular to the traveling direction). as a result,
The distribution of the fixing temperature on the recording material is acceptable and uniform,
Good image reproduction was obtained. In addition to this, no trouble occurred on the device. In Specific Example 12, the heating element of the heat roller is made longer than the width of the recording material (the direction perpendicular to the traveling direction) in the present electrophotographic copying machine, and passes through an area 1 cm or more inside from both ends of the heating roller. I did it. The heating value of the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became acceptable and uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device.

In Comparative Example 4, the heating element of the heat roller was made to have the same length as the recording material width (direction perpendicular to the traveling direction) in the present electrophotographic copying machine, and the area inside from both ends of the heating roller heating element was set. I tried to pass. Furthermore, the amount of heat generated by the heating element was not adjusted. As a result, the distribution of the fixing temperature on the recording material became non-uniform, and the fixing failure occurred near both ends, and there were missing characters and highlight highlights.

As described above, the heating element of the heat roller is made longer than the width of the recording material (direction perpendicular to the traveling direction),
By passing the area inside by 1 cm or more from both ends of the heat roller heating element, the fixing temperature in the width direction can be made uniform, and a printed matter excellent in image reproduction can be provided. Further, the fixing temperature can be made uniform by increasing the heat generation amount of the heat generating element of the heat roller at the end portion, and a printed matter excellent in image reproduction can be provided.

[0058]

In the image forming method as described above, the heating element is provided in a direction perpendicular to the recording material advancing direction, and the length of the heating element is made longer than the maximum width of the recording material so that the recording material generates heat. Since it passes through the inner area from both ends of the body, when printing or plate making as in the past, there are missing characters due to improper fixing at both ends of the recording material, highlight highlights, drop in saturation, etc. It becomes possible to stably form a high-quality image in which the image defect described above does not occur in a simple, inexpensive and short time. Furthermore, by increasing the amount of heat generated by the heating element at both ends, higher quality image formation can be achieved.
It becomes simple, inexpensive, and stable in a short time.

[Brief description of drawings]

FIG. 1 is a diagram showing an electrophotographic copying machine equipped with a fixing device of the present invention.

FIG. 2 is a diagram illustrating a length relationship of a recording material P of a heat roller 21 according to the present invention.

FIG. 3 is a diagram showing an example in which the fixing device of the present invention is applied to an inkjet printer.

FIG. 4 is a diagram showing an example in which the fixing device of the present invention is applied to an inkjet printer that transfers an image on a drawing drum onto a recording material using a transfer drum.

FIG. 5 is a diagram showing an example of a plate making machine using the fixing device of the present invention.

FIG. 6 is a diagram showing an example in which the fixing device of the present invention is applied to a toner jet.

[Explanation of symbols]

1 Image forming device 2 device body 3 scanning device 4 Platen 5 photoconductor drum 6 charged corotron 7 Developing device 8 Transfer device 11 Fixing device 12 Paper transport path 13 Matching device 15 Paper feeder 21 heat roller 21a cylindrical roller 21b heating element 21c Heating element winding 41 cassettes 43 Conveyor roller 44 Adhesive roller 45 carriage 451 recording head 46 drawing drum 47 Conveyor roller 48 output tray 49 Solvent Recovery Mechanism 56 drawing drum 55 carriage 551 recording head 52 transfer drum 51 cassettes 61 plate cylinder 62 ink roller 63 Dampening water roller 64 recording head 67 Blanket body 68 impression cylinder 69 Printing plate (paper plate) 650 toner jet recording device 651 recording section 652 brush roller 653 Aperture electrode 654 Supply roller 655 scraping member 656 feeding blade 659 drawing drum P Recording material

Claims (2)

[Claims] 1. An image forming apparatus having an image adding step of adding an image onto a recording material and a heat fixing step of heating and fixing the recording material to which the image is added, wherein the recording material is placed on a cylinder. An image forming method in which heat fixing is carried out in a state of mounting, wherein the heat fixing step has a heating element for applying heat to the recording material, and a pressure section for applying pressure simultaneously with heating, The heating element is provided in a direction perpendicular to the recording material traveling direction, and the length of the heating element is made longer than the maximum width of the recording material so that the recording material passes through the inner area from both ends of the heating element. A characteristic image forming method. 2. A cylinder, a recording material mounting means for mounting a recording material on the cylinder, and an image adding means for adding an image onto the recording material mounted on the cylinder by the recording material mounting means. And an image forming apparatus including: a heat fixing unit that heats and fixes a recording material having an image applied by the image applying unit on the cylinder;
In the image forming apparatus, wherein the heat fixing unit has a heating element that applies heat to the recording material and a pressurizing section that applies pressure simultaneously with heating, the heating element is provided in a direction perpendicular to the recording material traveling direction, An image forming apparatus, wherein the length of the heating element is longer than the maximum width of the recording material passage.