JP2003122186A - Image forming method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method and an image forming device by which a high-quality image can be formed simply, inexpensively and stably by uniformizing the fixing temperature of recording material in the case of performing fixation at a high speed. SOLUTION: In this image forming method at least having a stage for attaching material to be recorded, an image imparting stage for adding the image to the material to be recorded and a thermal fixing stage for thermally fixing the material to be recorded to which the image is added and forming the image on the material to be recorded, the thermal fixing stage consists of two stages, that is, a 1st fixing stage for heating the recording material to which the image is imparted in a non-contact state, and a 2nd fixing stage for applying pressure simultaneously with heating. In the 1st fixing stage, output at the thermal fixing time is changed once or more, especially, output at the thermal fixing time is made maximum when the thermal fixing is started and made minimum when the fixing is finished.

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. And a fixing device for uniformly fixing regardless of size.

[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 imagewise on a recording medium having a charge retention ability by using an ion emission head, and the electrostatic latent image is developed with dry or wet toner and then heated. An image is formed by fixing.

On the other hand, in the ink jet printer, it is usual that ink is ejected from the recording head onto the recording paper, 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 addition to the case of directly printing on a recording sheet as a recording medium such as a printer / facsimile as described above, in a system for producing a printing plate used for printing, the purpose is to improve printing durability. Heat fixing technology is used. A heat roller having a heat source is usually used alone in the heat fixing device to fix the image on the recording material added from the outside. However, in order to obtain sufficient fixability in a short time when the heat roller nips the recording medium, it is necessary to hold the heat roller at a high temperature and perform fixing. Therefore, the heat roller is significantly deteriorated and its life is short. Further, in recent years, due to the demand for high-speed image formation, it has become necessary to perform fixing in a shorter time even in a heat fixing device, and in that case, the above-mentioned demands on the heat roller become more severe. . To solve these problems, it is known to raise the temperature of the recording medium in advance before fixing it with the heat roller to lower the fixing temperature of the heat roller to extend the service life and to perform fixing in a short time. Has been. A lamp heater or the like is used as a means for raising the temperature of the recording medium in advance.

Although it is possible to reduce the load on the heat roller by heating means such as a lamp heater, there is a problem that the heat of the heat roller is taken by the recording material to make the fixing of the image unstable. In the direction (fixing direction), the temperature uniformity is significantly impaired, and the image fixing is hindered.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a compact fixing method and apparatus capable of stably fixing in a short time and having a long life, and will be described below when a lamp heater and a heat roller having a heat source are used in combination. As an example, a problem to be solved by the present invention will be described. When an image is added to the recording material from the outside, the recording material is conveyed to the fixing unit. In the fixing section, the recording material is heated by the lamp heater and pressed and heated by the heat roller,
The image is fixed.

When the recording material starts to be heated, the heat diffuses to the rear part which is not heated in the recording material. For this reason,
The fixing temperature decreases at the leading portion and heat does not easily escape at the rear portion, so that the fixing temperature rises. When the fixing is performed with a constant output, the fixing temperature is low at the leading portion and becomes higher toward the rear portion.

Immediately after the recording material is heated, the fixing temperature particularly at the leading end is lowered, and the temperature uniformity is remarkably impaired in the length direction (fixing direction), which hinders fixing. That is, the temperature of the recording material is lowered at the leading portion of the recording material, resulting in improper fixing. When printing is performed using a technique such as an electrophotographic copying machine or an inkjet printer, the leading portion of the recording material having a low heating temperature is Image defects such as cracks and highlight highlights occur. In addition, even when this fixing technology is used in a plate making machine that uses technology such as electrophotography and ink jet, fixing failure occurs at the beginning of the recording material, resulting in images such as missing characters and highlight highlights. Problems such as defects and deterioration of printing durability occur. In order to eliminate the poor fixing at the leading part of the recording material,
If the output of the lamp heater / heat roller is simply increased while the output is constant, the fixing temperature rises in the rear part, which causes image defects and deformation of the recording material due to excessive fixing, and the device easily breaks down.

The present invention is intended to solve the above-mentioned problems, and makes it possible to make the fixing temperature of the recording material uniform when fixing at a high speed, and to form a high-quality image in a simple, inexpensive and stable manner. The purpose is to do.

[0010]

In order to achieve the above object, the invention of an image forming method according to claim 1 is at least a step of mounting a recording material, and adding an image on the recording material. In an image forming method for forming an image on the recording material, which comprises an image applying step and a heat fixing step of performing heat fixing on the recording material to which an image has been added, And a second fixing step in which pressure is applied simultaneously with heating, and in the first fixing step, the first fixing step in which the recording material provided with The feature is that the output is changed once or more. According to a second aspect of the present invention, in the image forming method according to the first aspect, the output at the time of heat fixing in the first heat fixing step is maximized at the start of heat fixing and / or minimized at the end of fixing. Characterize. Claim 3
The invention of the described image forming apparatus is a recording material mounting means for mounting a recording material, an image adding means for adding an image on the mounted recording material, and a recording material to which an image is added by the image adding means. In an image forming apparatus having a heat fixing means for heat fixing to a material, the heat fixing means comprises a first fixing means for heating the recording material on which an image is applied in a non-contact manner, and a first fixing means. A second fixing means for further applying pressure to the heated recording material simultaneously with heating, and an output control mechanism for changing the output at the time of heat fixing at least once in the first fixing step. To do. According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the first fixing unit is a lamp heater and the second fixing unit is a heat roller. According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect, the output control mechanism for controlling the first fixing unit maximizes the output at the time of heat fixing at the start of heat fixing, and / or heat. It is characterized in that it is minimized at the end of fixing.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. As the image forming method according to the present invention, any 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, and inkjet, and the above method can be applied,
It can also be suitably used in a combined system. Thus, according to the present invention, by an inexpensive and simple means,
It is possible to obtain a clear and high-quality image. Next, a configuration example of an image forming apparatus used for carrying out the image forming method of the present invention will be shown. 1 is an example in which the present invention is applied to an electrophotographic copying machine, FIG. 2 is an example in which it is applied to an inkjet printer, FIG. 3 is an example in which it is applied to a plate making machine using an inkjet, and FIG. 4 is an example in which it is applied to a toner jet. Shows.

First, an example applied to an electrophotographic copying machine is shown in FIG.
It will be described based on. FIG. 1 is a cross-sectional view of an electrophotographic copying machine. An image forming apparatus 1 of the electrophotographic copying machine includes a platen 4 on an apparatus body 2 as in the case of a general electrophotographic copying machine.
Are arranged. 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 photosensitive 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, toner is supplied from the developing device 7 to adhere the toner to the electrostatic latent image, and 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 by the transfer device 8 by the force of the electric field. Here, the recording material is fed sheet by sheet from the sheet feeding unit 15, but the feeding method is not limited to this, and for example, a sheet 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 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 unit. The fixing unit includes a near infrared lamp heater 20 and a heat roller 21 that pressurizes and heats copy paper. The fixing unit is provided with a lamp heater 20 that heats the paper to a predetermined surface temperature in advance on the upstream side of the heat roller 21. Before the fixing by the heat roller 21, the paper is heated to a desired temperature in advance. As a result, it is not necessary to heat the recording material only with the heat roller 21, so the set temperature of the heat roller 21 can be lowered. In the lamp heater 20, although depending on the material of the heat roller 21, when the set temperature of the heat roller 21 is increased, the rubber material forming the heat roller 21 is deteriorated at an accelerated rate, and a monomer component or an additive that is a rubber material is added. So-called'crying out 'that elutes
May occur. On the other hand, by using the lamp heater 20 together, it is not necessary to set the heat roller 21 to a high temperature, the durability of the heat roller 21 is improved, and the problem of “crying out” is eliminated. In addition to this, when the heat roller 21 has a high temperature, the roller bearing may deteriorate, but by using it together with the lamp heater 20, the setting can be lowered and the bearing deterioration can be prevented. The temperature of the heat roller 21 is 30 ° C.
It is preferably 250 ° C, more preferably 60 ° C.
~ 200 ° C. Further, by heating the recording material in advance before fixing by the heat roller 21, the fixing time can be shortened. Further, it is desirable to define the time from the lamp heater 20 to the fixing by the heat roller 21 so that the influence of the heating by the lamp heater 20 remains even when the fixing by the heat roller 21. The time difference due to is within 7 seconds.

Here, the lamp heater 20 is used as the first fixing step and the heat roller 21 is used as the second fixing step, but any material can be applied as long as it heats the recording material in the first fixing step. You can For example, various lamp heaters such as the above-mentioned near-infrared lamp heater and far-infrared lamp heater, and radiation and radiation heaters such as a ceramic heater can be applied. In the second fixing step, the heat roller 21 is used, but any material that can apply pressure simultaneously with heating can be applied. For example, a belt fixing device or the like can be preferably used. Further, in addition to the first fixing unit and the second fixing unit, it is possible to appropriately provide a fixing unit to which heat or pressure is applied. For example, the number of heating means may be increased and two or more heat rollers and lamp heaters may be used.

The sheet on which the toner image has been transferred is inserted into the fixing section and then heated by the lamp heater 20 to raise its temperature. After that, by applying pressure while heating with the heat roller 21, the toner on the paper is pushed into the paper in a softened or melted state so that the toner permeates and the fixing property is promoted.
Although the case where the heating / pressurizing fixing is performed by the heat roller 21 after the heating by the lamp heater 20 is described here, the lamp heater 2 is processed after the heating by the heat roller 21.
Even if 0 is used, the effect is small, but the heat roller 21
It is possible to provide better fixing property than in the case of using alone. The heat roller 21 is usually made of Si rubber, but a rubber roller made of fluorine-based rubber or NBR-based rubber may be used, or another material may be used. Also,
The surface of the rubber roller may be covered with a resin sheet having a predetermined thickness (for example, 50 to 500 μm). Here, in order to obtain sufficient fixing property as the nip pressure of the heat roller 21,
0.05 MPa to 250 MPa, more preferably 0.
It is 1 to 20 MPa.

In the fixing unit 11, heating by the lamp heater 20 and heating and pressurization by the heat roller 21 are performed, but the output of the lamp heater 20 can be modulated during fixing of the recording material by the lamp heater output control means (not shown). It has a structure. Here, the output of the lamp heater 20 is
The recording material is set to have the largest size immediately after being inserted into the fixing device. The output of the lamp heater to be modulated depends on the structure of the device. The output of the lamp heater 20 at the leading end is preferably 103 to 300%, and more preferably 105 to 200% of the average output during fixing. The output of the lamp heater 20 at the rear end is preferably 15 to 97% of the average output during fixing, and more preferably 25.
~ 95%.

The number of times the output of the lamp heater 20 is modulated is at least once. The number of times the modulation is performed is determined by the size of the recording material and the temperature latitude of the material used. Here, the recording material size is A5, B5
For example, when the output is small, the output of the lamp heater 20 may be modulated only about once. However, in the case of a large size of B4 or more, the number of times of modulation may need to be increased. Further, when the usable temperature range is narrow relative to the fixing temperature of the recording material to be used and the resin containing the resin to be attached to the recording material from the outside, the number of times of modulation is increased to make the temperature more precise. There is a need. As a method of precisely controlling the temperature, there is a method of increasing the number of times stepwise as described above, but the output of the lamp heater 20 may be continuously changed. Further, the output control may be performed while detecting the amount corresponding to the temperature on the recording material.

The heat roller 21 is constructed so that the surface temperature becomes constant, and the output is controlled by the surface temperature obtained by means (not shown) for detecting the surface temperature to keep the surface temperature constant. The output is controlled by the time for which the voltage is applied, but the control method is not limited to this, and there is also a means for modulating the voltage applied to the heating element. 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 copy paper on which the fixing process has been performed is then discharged to the discharge tray 14. The image forming apparatus 1
In order to feed the paper toward the image transfer section of the main body 2,
A paper feeding section 15 is arranged below the apparatus main body 2, and a paper is sent out by using a carrying roller device 16. still,
The sizes of paper applied to this device are A3, A4, A5,
Although the sizes are B4 and B5, the present fixing technique is effective regardless of the paper size, and is also effective for A3w size, postcard, and envelope printing in addition to large sizes such as A1, A2, B1, and B2.

The above 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 above-described embodiment, the case where the electrophotography is applied as the image providing means has been described, but the application to the printer, the facsimile, the plate-making machine, etc. using the technology such as ionography and ink jet, in addition to the electrophotographic method. Is possible. 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.

<Examples 1 and 2> Next, the present invention is applied to the above-mentioned copying machine, and the lamp heater 20 and the heat roller 21 are adjusted and heated so that the recording material can be heated at about 120 ° C. It was fixed. Prior to fixing the heat roller 21 (manufactured by Hitachi Metals, Ltd.), the temperature of the recording material was raised to 100 ° C. by a near infrared lamp heater. The fixing conditions were that the surface temperature of the heat roller 21 was 150 ° C., the conveying speed of the recording material was 15 mm / sec, and the pressure (nip pressure) applied to the recording material by the heat roller 21 was 0.8 MPa.

[0022]

[Table 1]

Below, based on Table 1, the surface temperature of the recording material and the image reproducibility when the lamp heater output control mechanism is provided will be verified. Lamp heater 20 and heat roller 2
The output of the lamp heater 20 is adjusted in the first embodiment.
The output control mechanism of No. 2 was provided, the output modulation was performed twice, and printing was performed. As a result, the fixing temperature distribution on the recording material was uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device.

On the other hand, in Example 2, the output control mechanism of the lamp heater was provided, the output modulation was performed once, and the printing was performed.
As a result, the uniformity of the fixing temperature distribution on the recording material was inferior to that of Example 1, but good image reproduction was obtained. The temperature of the heat roller 21 remained at the set value and remained at 150 ° C. In addition to this, no trouble occurred on the device.

On the other hand, in Comparative Example 1, printing was performed without providing the output control mechanism of the lamp heater and without performing output modulation. As a result, the fixing temperature distribution on the recording material becomes uneven, the temperature is lowered at the tip. On the obtained printed matter, at the beginning of fixing (position at which fixing starts), character missing due to defective fixing and image blurring were observed. In addition to this, no trouble occurred on the device. In Comparative Example 2, the output control mechanism of the lamp heater was not provided, the output modulation was not performed, and only the output of the lamp heater was increased to perform printing.
As a result, the temperature increased at the trailing edge while the fixing temperature distribution on the recording material remained uneven. On the resulting print,
At the rear end of the fixing (position where the fixing ends), hot offset due to excessive fixing and deformation of the recording material (paper) were observed.
In addition, when printing was performed continuously, the temperature inside the apparatus increased and abnormal noise was heard from the bearing portion of the heat roller. As described above, by providing the output control mechanism of the lamp heater and performing the output modulation, the fixing temperature can be made uniform, a printed matter excellent in image reproduction can be provided, and a structure that does not cause apparatus trouble can be obtained. .

<Embodiments 3 to 4> Next, an example in which the present invention is applied to an ink jet printer is shown in FIG. FIG. 2 shows a cross section of an image recording apparatus having an inkjet recording apparatus as an image providing unit. Inkjet recording device 3
The recording material P, which is a recording sheet or a resin sheet, is provided on the bottom of 0.
A cassette 31 containing is loaded. A conveyance roller pair 32 and a recording head 33 are provided on the downstream side of the recording material conveyance direction.
A carriage 33 carrying a is arranged. The recording head 33a is a share mode 500-channel piezo inkjet device (XaarJe manufactured by Xaar).
t500S) and an oil-based ink (manufactured by the same company). The drawing resolution was 720 dpi, and the dot size was changed in 8 steps to control the gradation. The recording material P is conveyed and attached to the drawing position by the conveying roller 32, and dust is removed before the image is applied by the inkjet recording device. Although the dust is removed by imparting adhesiveness to the transport roller 32 here, an adhesive roller for dust removal may be provided separately from the transport roller 32. The dust removal method is a method of adsorbing the dust on the surface with an adhesive roller, but the method is not limited to this, and there is also a method of removing it with an air flow, for example.

The recording material P is then conveyed below the recording head 33a, and drawing is performed. On the other hand, the discharge roller pair 34 and the transport roller pair 32 before and after the drawing process are interlocked with each other, and the discharge roller pair 34 has a rotational speed slightly higher than that of the transport roller pair 32, which is suitable for a recording material. It has tension. The recording head 33a ejects ink while moving in a direction perpendicular to the paper surface by the carriage 33,
An image corresponding to the image signal is drawn. At this time, the recording material P
In the above, image drawing with a constant width is performed. That is, on the recording material P, the conveyance roller pair 3 is set every time one line of drawing is completed.
2, the recording material P is conveyed by one line and the next line is drawn. Such an operation is repeated, and the sheet is sequentially conveyed to the heating and fixing section 11 by the pair of sheet discharging rollers 34.
When the drawing is completed, the lamp heater 2 is
0, after fixing by the heat roller 21, it is ejected to the paper ejection tray 38, and the recorded paper P is taken out from here.

The heating and fixing conveyance path 35 has a smooth surface shape so that the conveyance at the time of fixing can be smoothly carried out. The recording material P discharged from the recording section (33, 33a) is smoothly carried into the heat fixing section 11. In the heat fixing unit 11, heating by the lamp heater 20 is performed prior to heat / pressure fixing by the heat roller 21. The output of the lamp heater 20 is modulated by an output control mechanism (not shown) from the start of fixing to the end of fixing. As a result, the fixing temperature is stabilized and stable fixing properties can be provided.

The solvent in the ink is vaporized by the drawing and fixing operations to fill the inside of the machine. Therefore, the area enclosed by the broken line has an improved hermeticity, and a solvent recovery mechanism 36 is provided to recover the vaporized solvent in the machine. In the collecting method, the air inside the machine is sent to the solvent collecting mechanism 36, and this is cooled by the refrigerant cooling section 36a, so that the solvent is liquefied and collected in the solvent collecting section 36b, and the air after solvent separation is sent back to the inside of the machine. As a result, the solvent vapor generated inside the machine is removed, the inside of the machine is not contaminated, and the solvent vapor does not cause an offensive odor when diffused outside the machine. Here, the solvent vapor is sealed in the heat fixing unit, but the heat fixing unit may be included, and the sealed range is not limited to this. For example, the area including the heat fixing section and the drawing section (recording head) may be hermetically sealed to remove the solvent. Although the method of directly drawing and fixing on the recording material P has been described above, the image forming method is not limited to this, and an image formed on the drawing drum by using a transfer drum as shown in FIG. May be transferred to the recording material. Further, the recording material P may be supplied other than the cassette, and may be supplied by a roll, for example.

According to the present invention, the image is solidified by heating by fixing with a heat roller (manufactured by Hitachi Metals, Ltd.),
Prior to the heat roller fixing, the temperature of the recording material was heated to 70 ° C. by a near infrared lamp heater. The fixing conditions are a heat roller temperature of 145 ° C. and a recording material conveying speed of 18 mm /
sec, the applied pressure (nip pressure) of the heat roller 21 to the recording material is 0.7 MPa.

[0031]

[Table 2]

Below, based on Table 2, the surface temperature of the recording material and the image reproducibility when the output control mechanism of the lamp heater according to the present invention is provided will be verified. The output of the lamp heater 20 and the heat roller 21 was adjusted. In Example 3, the output control mechanism of the lamp heater 20 was provided, the output modulation was performed twice, and printing was performed. As a result, the fixing temperature distribution on the recording material was uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device. On the other hand, in Example 4, the output control mechanism of the lamp heater 20 was provided, the output modulation was performed once, and printing was performed. As a result, the uniformity of the fixing temperature distribution on the recording material was inferior to that of Example 3, but good image reproduction was obtained. The temperature of the heat roller 21 remained at the set value and remained at 150 ° C. In addition to this, no trouble occurred on the device.

On the other hand, in Comparative Example 3, printing was performed without providing the output control mechanism of the lamp heater 20 and without performing output modulation. As a result, the fixing temperature distribution on the recording material became non-uniform, and the temperature decreased at the tip. On the obtained printed matter, at the beginning of fixing (position at which fixing starts), character missing due to defective fixing and image blurring were observed. Besides this,
No troubles occurred on the device. In Comparative Example 4, the output control mechanism of the lamp heater 20 was not provided, the output modulation was not performed, and only the output of the lamp heater 20 was increased to perform printing. As a result, the temperature increased at the trailing edge while the fixing temperature distribution on the recording material remained uneven. On the obtained printed matter, hot offset and deformation of the recording material (paper) due to excessive fixing were observed at the rear end portion of the fixing (position where the fixing ends). In addition, when printing was performed continuously, the temperature inside the apparatus increased and abnormal noise was heard from the bearing portion of the heat roller. As described above, by providing the output control mechanism of the lamp heater and performing the output modulation, the fixing temperature can be made uniform, a printed matter excellent in image reproduction can be provided, and a structure that does not cause apparatus trouble can be obtained. .

<Embodiments 5 to 6> FIG. 3 shows an image forming apparatus including a transfer drum and a drawing drum, which is a plate making machine. Plate making machine 4
0 is loaded with a cassette 41 containing a recording material P which is a plate material at the bottom thereof, and is conveyed to the transfer drum 48 via a conveyance roller 42 on the downstream side in the recording material conveyance direction.
It is installed. On the other hand, the recording head 43 a is arranged near the drawing drum 46 by the carriage 43. As the recording head 43a, a piezo ink jet device (Ep
Son-made Calario PM750C) is used, and X
Drawing is performed using an oil-based ink manufactured by aar. By continuing the rotation of the drawing drum 46 on which the image is formed, the ink formed like the image moves to the pressing contact portion with the transfer drum 48, and is transferred to the recording material P on the drawing drum 46 at the pressing contact portion. It The recording material transferred in this way is conveyed to the heating and fixing section 11, and the fixing is performed by the lamp heater 20 and the heat roller 21 in the heating and fixing section 11. In the heat fixing unit 11, heating by the lamp heater 20 is performed prior to heat / pressure fixing by the heat roller 21. The output of the lamp heater 20 is modulated by an output control mechanism (not shown) from the start of fixing to the end of fixing. As a result, the fixing temperature is stabilized, and stable fixing properties can be imparted to the plate material.

A plate making machine 4 having the structure shown in FIG.
The piezo-type inkjet device head 43 described above was mounted on No. 0, and the gap was adjusted to 1.5 mm. The image data is transmitted to the arithmetic control unit, and using 32 channels,
The drawing drum 46 was rotated, the ejection head was moved to eject and draw ink on the drawing drum 46, and this was transferred to the paper plate loaded on the transfer drum 48 (drawing resolution 720 dpi). 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 surfaces of high-quality paper (100 g / m 2). Further, the dispersion prepared as follows on this support was dried to give a coating amount of 5 g / m2.
An image receiving layer was provided so as to obtain a paper plate material.

[0036] ・ Dispersion A   Gelatin (Wako Pure Chemicals first grade) 2g   Colloidal silica (Nissan Chemical; Snowtex C, 20% aqueous solution) 13g   Silica gel (Fuji 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.

Further, according to the present invention, the heat roller 21
(Manufactured by Hitachi Metals, Ltd.) The image was strengthened by heating by fixing and a printing plate was prepared. Prior to fixing the heat roller 21, the temperature of the recording material was heated to 80 ° C. by the near infrared lamp heater 20. Fixing condition is heat roller temperature 15
5 ° C., conveying speed of recording material 15 mm / sec, pressure of heat roller 21 applied to recording material (nip pressure) 0.3 MP
a, and the output of the lamp heater 20 and the heat roller 21 was adjusted so that the temperature on the recording material was about 95 ° C. to obtain a printing plate. After that, the obtained printing plate is set in a printing machine, printing ink and dampening water are applied, the printing ink image is transferred onto a blanket cylinder rotating with the plate cylinder, and the space between the blanket cylinder and the impression cylinder is transferred. Printing was performed by transferring the printing ink image on the blanket cylinder onto the printing coated paper passing therethrough.

[0038]

[Table 3]

The surface temperature and image reproducibility of the recording material when the output control mechanism of the lamp heater according to the present invention is provided will be verified based on Table 3 below. The output of the lamp heater 20 and the heat roller 21 was adjusted. In Example 5,
An output control mechanism for the lamp heater 20 is provided to control the output modulation.
It performed once and plate-making was performed. As a result, the fixing temperature distribution on the recording material was uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device. On the other hand, in Example 6, the output control mechanism of the lamp heater 20 was provided, the output modulation was performed once, and the plate making was performed. As a result, although the uniformity of the fixing temperature distribution on the recording material was inferior to that of Example 5, good image reproduction was obtained. The result of printing using this paper plate was also good. In addition to this, no trouble occurred on the device.

On the other hand, in Comparative Example 5, plate making was performed without providing an output control mechanism for the lamp heater 20 and without performing output modulation. As a result, the fixing temperature distribution on the recording material became non-uniform, and the temperature decreased at the tip. As a result of printing using this paper plate, fixing failure occurred at the beginning of fixing (position where fixing starts), and letters were missing on the printed matter. In Comparative Example 6, the lamp heater 20 was not provided with an output control mechanism and output modulation was not performed.
The plate was produced by increasing the output only. As a result, the temperature increased at the trailing edge while the fixing temperature distribution on the recording material remained uneven. As a result of printing using this paper plate, on the obtained printed matter, hot offset and deformation of the recording material (paper) due to excessive fixing were observed at the rear end portion of the fixing (position where the fixing ends). In addition, when printing was performed continuously, the temperature inside the apparatus increased and abnormal noise was heard from the bearing portion of the heat roller. As described above, by providing the output control mechanism of the lamp heater and performing the output modulation, the fixing temperature can be made uniform, a printed matter excellent in image reproduction can be provided, and a structure that does not cause apparatus trouble can be obtained. .

<Embodiments 7 to 8> The toner jet recording apparatus shown in FIG. 4 has a recording unit 51 and the thermal fixing unit 1 according to the present invention.
1 and 1. The toner jet recording apparatus has a paper feed cassette 3 for loading a paper P to be recorded.
1 and a paper discharge tray 3 for taking out the recorded paper P
And 8 are provided. In the recording unit 51, an image is recorded on the paper P that is inserted from the paper feed cassette 31 and conveyed by the pair of conveyance rollers 32. Then, the image recorded on the paper P is fixed in the heat fixing unit 11. Further, the paper P passes through the pair of transport rollers 37,
It is sent to the outlet 38.

The recording section 51 includes a rotatable brush roller 52 having a brush for charging the toner T, an aperture electrode 53, and an opposing electrode provided to face the aperture electrode 53 at a predetermined interval. It is composed of a drawing drum 59 having a function. The drawing drum 59 is connected to the power source E2 (minus). The heat fixing unit 11 includes a lamp heater 20 having a heat source and a heat roller 21. The paper P is mounted on the drawing drum, and when the drawing is completed, the paper P passes under the lamp heater 20 and the heat roller 21 and is arranged so as to be fixed.

Around the brush roller 52, a supply roller 54, which is rotatable according to the rotation direction of the brush roller 52 and supplies the toner T to the brush roller 52, and the toner T attached to the brush of the brush roller 52 are repelled. And a scraping member 55 for contacting the brush roller 52. Further, the toner T
A supply blade 56 for supplying a uniform thickness to the supply roller 54 is provided in contact therewith. This supply blade 5
Toner T is stored on top of 6. Supply roller 54
The supply blade 56 is covered with the case K. The aperture electrode 53 is provided above the brush roller 52.

When a well-known image forming signal and image data are input from an external device (not shown), the paper P inserted from the insertion cassette 31 is fed to the recording section 51 by the feed roller 32.
Be transported to. In the recording unit 51, the supply blade 5
The toner T is pressed against the supply roller 54 by 6 and carried on the surface of the supply roller 54. Supply roller 5
By the rotation of 4, the toner T is supplied to the brush roller 52. At this time, the toner T is, for example, positively (+) charged by friction with the brush while being in contact with the supply roller 54 and the brush roller 52. The positively charged toner T is carried on the brush roller 52.

In the vicinity of the aperture electrode 53, the scraping member 55 scrapes the brush of the brush roller 52 as the brush roller 52 rotates. Then, when the brush returns to its original position due to elasticity, the toner T carried in an appropriate amount on the brush is
Bounce up to form a cloud shape, and the aperture electrode 53
Is supplied to. At this time, the voltage applied from the signal source S to each control electrode layer of the aperture electrode 53 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 59. After that, the paper P on which the toner T is attached is conveyed to the thermal fixing unit 11. According to the present invention, the image is fixed by heating by heat roller fixing. Prior to heat roller fixing, the temperature of the recording material is set to 110 ° C. by the near infrared lamp heater 20.
Heated up. Fixing conditions are heat roller temperature 175 °
C, recording material conveying speed 12.5 mm / sec, heat roller 21 applied pressure (nip pressure) to recording material 1.2 M
The output of the lamp heater 21 and the heat roller 21 was adjusted so that the temperature was Pa and the temperature rise of the recording material was about 130 ° C. The paper P on which the fixing is completed is conveyed by the transport roller 19
The sheet is conveyed to the sheet discharge tray 18 via the sheet and is carried out.

In the above-described example, the recording material is mounted on the drawing drum and the recording material on which the image is drawn is discharged. However, the structure of the apparatus is not limited to this, and a transfer drum is provided and drawing is performed on the drawing drum. Then, the image may be transferred onto a sheet on a transfer drum, and the image may be fixed and discharged. Further, the supply of the recording material is not limited to the cassette, but may be a roll, for example.

[0047]

[Table 4]

Based on Table 4 below, the surface temperature of the recording material and the image reproducibility when the output control mechanism of the lamp heater according to the present invention is provided will be verified. The output of the lamp heater 20 and the heat roller 21 was adjusted. In Example 7, the output control mechanism of the lamp heater 20 was provided, the output modulation was performed twice, and printing was performed. As a result, the fixing temperature distribution on the recording material was uniform, and good image reproduction was obtained. In addition to this, no trouble occurred on the device. On the other hand, in Example 8, the output control mechanism of the lamp heater 20 was provided, the output modulation was performed once, and the printing was performed. As a result, the uniformity of the fixing temperature distribution on the recording material was inferior to that of Example 7, but good image reproduction was obtained. The temperature of the heat roller 21 remained at the set value and remained at 150 ° C. In addition to this, no trouble occurred on the device.

On the other hand, in Comparative Example 7, printing was performed without providing the output control mechanism of the lamp heater 20 and without performing output modulation. As a result, the fixing temperature distribution on the recording material became non-uniform, and the temperature decreased at the tip. On the obtained printed matter, at the beginning of fixing (position at which fixing starts), character missing due to defective fixing and image blurring were observed. Comparative Example 8
Then, the output control mechanism of the lamp heater 20 was not provided, the output modulation was not performed, and only the output of the lamp heater 20 was increased to perform printing. As a result, the temperature increased at the trailing edge while the fixing temperature distribution on the recording material remained uneven. On the obtained printed matter, the rear end of the fixing (the position where the fixing ends)
Hot offset due to excessive fixing, recording material (paper)
Deformation was seen. In addition, when printing was performed continuously, the temperature inside the apparatus increased and abnormal noise was heard from the bearing portion of the heat roller. As described above, by providing the output control mechanism of the lamp heater and performing the output modulation, the fixing temperature can be made uniform, a printed matter excellent in image reproduction can be provided, and a structure that does not cause apparatus trouble can be obtained. .

[0050]

As described above, according to the present invention, at least a step of mounting a recording material, an image applying step of adding an image on the recording material, and the recording operation to which the image is added In the image forming method for forming an image on the recording material, the method comprises the step of heating and fixing the material to the recording material, wherein the heating and fixing step heats the recording material to which the image is applied in a non-contact manner. It comprises two steps, a first fixing step and a second fixing step in which pressure is applied simultaneously with heating, and in the first fixing step, the fixing temperature is changed by changing the output at the time of heating and fixing once or more. It is possible to provide a printed matter that can be made uniform and has excellent image reproduction, and to obtain an image forming method and apparatus that do not cause apparatus trouble.

[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 showing an example in which the fixing device of the present invention is applied to an inkjet printer.

FIG. 3 is a diagram showing an example of a plate making machine using the fixing device of the present invention.

FIG. 4 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 20 lamp heater 21 heat roller

Claims (5)

[Claims] 1. At least a step of mounting a recording material, an image applying step of adding an image on the recording material, and a heat fixing step of performing heat fixing on the recording material having an image added thereto. In the image forming method for forming an image on the recording material, the heat fixing step includes a first fixing step of heating the recording material having an image in a non-contact manner, and a pressure at the same time as the heating. In the first fixing step, the output at the time of heat fixing is 1
An image forming method characterized by changing the number of times more than once. 2. The image forming method according to claim 1, wherein the output at the time of heat fixing in the first heat fixing step is maximized at the start of heat fixing and / or minimized at the end of fixing. 3. A recording material mounting means for mounting a recording material, an image applying means for applying an image onto the mounted recording material, and a heat fixing to the recording material to which an image is applied by the image applying means. In the image forming apparatus having a heating and fixing means for performing the above, the heating and fixing means heats the recording material on which an image has been applied in a non-contact manner, and an object to be heated by the first fixing means. An image forming apparatus, further comprising a second fixing unit for applying pressure to the recording material at the same time as heating, and an output control mechanism for changing the output at the time of heat fixing at least once in the first fixing step. . 4. The image forming apparatus according to claim 3, wherein the first fixing unit is a lamp heater and the second fixing unit is a heat roller. 5. The output control mechanism for controlling the first fixing unit maximizes the output at the time of heat fixing at the start of heat fixing and / or minimizes the output at the end of heat fixing. 4. The image forming apparatus according to item 4.