JP2004252162A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method which prevents image degradation by a static transfer system and produces high-quality images, in an image forming apparatus which performs simultaneous image transfer to both sides of a recording medium and which has also an excellent energy saving effect. <P>SOLUTION: The image forming method includes: a first transfer step in which a first visible image supported by a first image carrier 10 is transferred to a second image carrier 100 kept in contact with the first image carrier 10 by applying heat and pressure; a second transfer step in which the first image carrier 10 supports a second visible image and this second visible image supported by the first image carrier 10 and the first visible image supported by the second image carrier 100 are simultaneously transferred to both sides of a recording medium P by applying heat and pressure; and a fixing step in which the first and second visible images on the recording medium P are melted and stuck on the medium P. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus, and more specifically, to form a color image almost simultaneously on both sides of a recording medium in a single recording medium transporting step without reversing and transporting the recording medium. The present invention relates to an image forming apparatus capable of performing the following.
[0002]
[Prior art]
2. Description of the Related Art An electrophotographic image forming apparatus capable of forming a color image on both sides of a recording medium almost simultaneously in a single recording medium transporting step without reversing and transporting the recording medium has been proposed.
For example, an image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 9-258518 has the following configuration. A developing device using a plurality of color toners is arranged around one photoreceptor, exposure and development are performed for each color, a visualized image is superimposed on the photoreceptor surface, and a first intermediate transfer member is formed from a portion where all the colors have been superimposed. To the toner image receiving member (second intermediate transfer member). Once again, the toner image is superimposed on the surface of the photoreceptor, electrostatically collectively transferred to the first intermediate transfer body, and the toner image is collectively electrostatically transferred to both sides of the sheet from the toner image receiver and the first intermediate transfer body It is to do. In this image forming apparatus, the transfer of the toner image from the photosensitive member to the first intermediate transfer member, the transfer from the first intermediate transfer member to the toner image receiver, and the transfer of the toner image from the toner image receiver and the first intermediate transfer member are performed. All transfer to paper is performed by electrostatic transfer. In general, in the case of the electrostatic transfer method, it is good to perform the transfer when the recording medium and the image carrier are in close contact with each other. And bleeding is caused by the influence of the image, and image deterioration occurs. Therefore, there is a problem that an obtained image is an image having low sharpness.
[0003]
Japanese Patent Application Laid-Open No. 2000-250272 discloses a tandem-type image forming unit in which a belt-shaped first intermediate transfer member is brought into contact with four photoconductors corresponding to each color, and a belt-shaped second intermediate transfer member is brought into contact therewith. An image forming apparatus in which the intermediate transfer member is configured to be able to come and go is disclosed. The toner images formed on the respective photoconductors in the image forming units of the respective colors in accordance with the image information on the first surface of the document are superimposed on the first intermediate transfer member to form a color toner image. The toner image transferred on the first intermediate transfer member is thermally transferred to a second intermediate transfer member by a heating unit provided on the first intermediate transfer member, and is carried on the second intermediate transfer member. . Thereafter, a toner image is formed again on each photoconductor in accordance with the image information on the second surface of the document, and is sequentially superimposed on the first intermediate transfer body to form a color toner image. Thereafter, the recording medium is conveyed between the first intermediate transfer body and the second intermediate transfer body, the color toner images carried by both intermediate transfer bodies by the heating means provided on the first intermediate transfer body, The heat transfer is performed on both sides of the recording medium at the same time as the fixing.
In this image forming apparatus, the primary transfer from the photoreceptor to the first intermediate transfer body is performed by electrostatic transfer, but the secondary transfer from the first intermediate transfer body to the second intermediate transfer body, The transfer from the intermediate transfer member and the second intermediate transfer member to both surfaces of the recording medium is performed by thermal transfer, and dust and bleeding of an image which are seen when a large number of electrostatic transfer steps are included are reduced. However, the transfer to both sides of the recording medium from the first intermediate transfer member and the second intermediate transfer member is of a configuration that also serves as fixing, and therefore, the first and second intermediate transfer members become hot. Therefore, a cooling means for cooling the toner to a temperature lower than the softening temperature after the transfer step is required. When such a configuration is applied to a high-speed machine, there is a problem that energy saving is poor, and the mounting of the cooling means causes an increase in the size of the device, which is impractical.
[0004]
[Problems to be solved by the invention]
In view of the above problems, the present invention is an image forming method or an image forming apparatus that performs simultaneous transfer to both sides of a recording medium, and can produce a high-quality image by preventing image deterioration due to an electrostatic transfer method. It is another object of the present invention to provide an image forming method and an image forming apparatus which are excellent in energy saving effects.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is to heat the first visualized image to a second image carrier that contacts the first image carrier that carries the first visualized image. And a first transfer step of transferring by application of pressure, and subsequently, the first image carrier carries a second visible image, and a second visible image carried by the first image carrier, A second transfer step of simultaneously transferring the first visible image carried by the second image carrier to both surfaces of the recording medium by applying heat and pressure; and a first visible image on the recording medium. And a fixing step of fusing and fixing the second visible image on the recording medium.
According to a second aspect of the present invention, in the image forming method according to the first aspect, a temperature applied to the first image carrier in the first transfer step and a second image applied in the second transfer step. This is an image forming method in which the temperature applied to the carrier is controlled in the range from the glass transition point temperature to the softening point temperature of the toner used for visual image formation.
According to a third aspect of the present invention, in the image forming method according to the first or second aspect, the toner is used in a plurality of colors corresponding to a color image formation, and the plurality of colors of the toner are glass transition. An image forming method in which one of the difference between the point temperatures and the difference between the softening points is within 7 ° C.
[0006]
According to a fourth aspect of the present invention, there is provided a first image bearing member for carrying a visual image formed based on image information, and a microscope contacting the first image bearing member and carrying the first image bearing member. A second image carrier on which the image is transferred and carried, and a visible image carried by the first image carrier is transferred to the second image carrier, or the first image carrier and / or A transfer unit A and a transfer unit B for transferring a visual image carried by the two image carriers to a recording medium conveyed to a contact portion between the first image carrier and the second image carrier; An image forming apparatus having at least a fixing unit for melting and fixing a visible image on a medium, wherein the transfer unit A and the second transfer unit B are transfer units that apply heat and pressure. .
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the temperature applied from the transfer unit A to the first image carrier, and the temperature applied from the transfer unit B to the second image carrier. This is an image forming apparatus in which the temperature applied to the body is controlled in the range from the glass transition temperature to the softening point of the toner used for visual image formation.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, a pressure applied from the transfer unit A to the first image carrier, and a pressure applied from the transfer unit B to the second image carrier. In the image forming apparatus, the pressure applied to the image carrier is ² to 10 N / cm ² .
[0007]
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the fourth to sixth aspects, the image forming apparatus further includes a latent image carrier for carrying a latent image, and a latent image carrier. A charging unit for uniformly charging the surface; an exposure unit for irradiating the surface of the latent image carrier with exposure light based on image information to form a latent image; and a latent image formed on the surface of the latent image carrier for visualization Developing device, and a primary transfer means for transferring the visible image on the latent image carrier to the first image carrier, the first image carrier is a primary intermediate transfer member, The second image carrier is an image forming apparatus that is a secondary intermediate transfer member.
According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the surface roughness Rz of each member of the latent image carrier, the primary intermediate transfer body, and the secondary intermediate transfer body is expressed. And the surface roughness Rz of the member of the secondary intermediate transfer member is smaller than the surface roughness Rz of the recording medium to be used.
According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the fourth to eighth aspects, the fixing unit is configured such that two fixing members for fixing toner on a recording medium have similar surface characteristics. Device.
According to a tenth aspect, in the image forming apparatus according to any one of the fourth to ninth aspects, the fixing member is a roller or a belt.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a central sectional view of the image forming apparatus according to the first embodiment of the present invention.
The recording medium P is stored in the lower sheet feeding devices 26-1 and 26-2 in FIG. 1, and the uppermost recording medium P is fed by the sheet feeding roller 27 one by one through a plurality of guides 29 and a pair of registration rollers. 28.
A static eliminator L, a cleaning device 2, a charging device 3, and a developing device 5 are provided on the outer peripheral portion of the latent image carrier 1 rotatably supported and rotating in the direction of the arrow. A space is provided between the charging device 3 and the developing device 5 for receiving optical information emitted from the exposure device 4. In the present embodiment, there are four latent image carriers 1 (a, b, c, d), but the configuration of image forming parts provided around each is the same. The colors of the color materials (toners) handled by the developing device 5 are different from each other.
As the latent image carrier 1, a photoconductor or the like in which a layer of an organic semiconductor as a photoconductive substance is provided on the surface of an aluminum cylinder having a diameter of about 30 to 100 mm can be used. A photoconductor having a surface layer of amorphous silicon may be employed. Incidentally, the latent image carrier 1 can be employed even if it is in the form of a belt.
The exposure device 4 irradiates optical information corresponding to color image formation on the surface of the uniformly charged latent image carrier 1 as a latent image by a known laser method. An exposure device comprising an LED array and an image forming means may be employed.
[0009]
Part of the latent image carrier 1 is in contact with the first image carrier 10. The first image carrier 10 is a belt-shaped primary intermediate transfer body 10 supported and stretched by rotating rollers 11, 12, and 13 so as to be movable in the direction of the arrow. The primary intermediate transfer member 10 is a belt made of a resin film or rubber having a substrate thickness of 20 to 600 μm, and has a resistance value that enables electrostatic transfer of toner from the latent image carrier 1. It is more preferable that the material is a heat-resistant material.
A primary transfer unit 20 is provided near the latent image carrier 1 inside the belt loop of the primary intermediate transfer body 10. As the primary transfer unit 20, a charger that discharges from the electrodes can be used, but it is particularly preferable to use a roller that applies a relatively low voltage as shown in FIG. This is because the roller transfer method at a low voltage can reduce transfer dust. The toner images of each color formed on the latent image carrier 1 are sequentially electrostatically transferred onto the primary intermediate transfer body 10 by the primary transfer means 20 and are superimposed to form a color toner image.
Further, among the rollers supporting the primary intermediate transfer member 10, the roller 11 is a transfer unit A having a built-in heating element. Further, one of these rollers or a separately provided roller is appropriately provided with a tension means for applying tension to the belt of the primary intermediate transfer body 10. The rollers except the primary transfer means 20 are grounded.
[0010]
A cleaning unit 25 is provided outside the belt loop of the primary intermediate transfer body 10. The cleaning unit 25 temporarily transfers the toner remaining on the surface of the primary intermediate transfer body 10 to the cleaning roller 25A, scrapes the toner with the blade 25B, and conveys the toner to the storage unit (not shown) by the collection unit 25C. A heating element is provided inside the cleaning roller 25A so that the toner remaining on the belt is softened and melted to facilitate removal from the belt. The surface roughness of the member used for the cleaning roller 25A is assumed to be greater than the surface roughness of the primary intermediate transfer member. As a material of the roller, copper or aluminum having good heat conductivity can be adopted.
[0011]
On the right side of the figure, a second image carrier 100 is provided so that a part thereof contacts the primary intermediate transfer body 10. The second image carrier 100 is a belt-shaped secondary intermediate transfer member 100 supported and stretched between rollers 110, 111, 112, and 113 that rotate movably in the arrow direction. The secondary intermediate transfer member 100 is a belt whose base is a resin film or rubber whose base has a thickness of 20 to 600 μm. It is more preferable that the material is a heat-resistant material. Inside the belt loop of the secondary intermediate transfer member 100, a roller 30 having a heating element therein is provided. The roller 30 is a transfer unit B30.
[0012]
A cleaning unit 250 is provided outside the belt loop of the secondary intermediate transfer member 100. The cleaning unit 250 temporarily transfers the toner remaining on the surface of the secondary intermediate transfer member 100 to the cleaning roller 250A, scrapes the toner with the blade 250B, and conveys the toner to the storage unit (not shown) by the collection unit 250C. A heating element is provided inside the cleaning roller 250A so that the toner remaining on the belt is softened and melted to facilitate removal from the belt. The surface roughness of the member used for the cleaning roller 250A is assumed to be greater than the surface roughness of the secondary intermediate transfer member. As a material of the roller, copper or aluminum having good heat conductivity can be adopted.
[0013]
Next, the transfer nip formed by the primary intermediate transfer member 10 and the secondary intermediate transfer member 100 will be described.
The primary intermediate transfer body 10 is pressed by the transfer unit A11, and the secondary intermediate transfer body 100 is pressed by the transfer unit B30, so that the primary intermediate transfer body 10 and the secondary intermediate transfer body 100 come into contact with each other, and the transfer nip portion To form The nip width is preferably 5 to 10 mm. The outer diameter of each roller of the transfer unit A11 and the transfer unit B30 is about 40 to 60 mm, and a rubber layer is provided on the surface as needed. The thickness of the rubber layer is determined in consideration of the thicknesses of the belts of the primary intermediate transfer member 10 and the secondary intermediate transfer member 100 so that a necessary nip width is obtained.
[0014]
In the transfer nip portion, a step a of transferring a visible image from the primary intermediate transfer body 10 to the secondary intermediate transfer body 100, and recording of a visible image carried by each of the primary intermediate transfer body 10 and the secondary intermediate transfer body 100 A transfer step b on both surfaces of the medium P is performed. In each of the transfer steps a and b, the temperature applied from the transfer unit A11 and the transfer unit B30 to the primary intermediate transfer body 10 and the secondary intermediate transfer body 100 is not less than the glass transition point temperature and not more than the softening point temperature of the toner to be used. Range of temperature. Here, the glass transition point temperature can be measured using a differential scanning calorimeter. Further, the softening point temperature is a temperature at which the toner is softened by heat and the deformation due to the load stops, and can be measured using a flow tester in accordance with the method described in JIS K7210.
When the toner is heated and pressed in the above temperature range, the toner in the transfer nip portion is plastically deformed and bites into and adheres to the uneven portion on the surface of the secondary intermediate transfer member 100 or the recording medium P. The transfer of the toner image onto the secondary intermediate transfer member 100 or the recording medium P in these transfer steps only needs to have an adhesive force that does not separate when the toner adheres to each surface. Therefore, the temperature in the transfer step is not required to be a temperature at which the toner is completely melted, and as described above, a temperature range from the glass transition temperature to the softening point at which the toner can be plastically deformed is good. Further, the pressure to be applied does not need to force the toner to bite into the irregularities on the surface of the secondary intermediate transfer member 100 or the recording medium P, and the pressure is preferably ^{2 to} 10 N / cm ² .
Further, in the present embodiment, a plurality of colors (four in the case of the configuration in FIG. 1) of toners are used in correspondence with color image formation. Therefore, the glass transition point temperature and the softening point temperature between these toners are used. Is preferably small. In particular, by using a toner in which one of the difference between the glass transition point temperature and the difference between the softening point temperatures is within the range of 7 ° C., the transferability between the toners does not change, and the toner is excellent. Transfer can be performed.
[0015]
In addition, in order to improve the transferability of the toner image in the transfer steps a and b, the surface roughness of each member of the latent image carrier 1, the primary intermediate transfer member 10, and the secondary intermediate transfer member 100 is Rz. It is preferable to increase the size in the order of the notation. This is because when the toner is plastically deformed in the transfer nip portion, the transfer of the toner is likely to occur on a member surface having a rougher surface roughness. Therefore, as described above, the surface roughness Rz of each member is increased in the order of the latent image carrier 1, the primary intermediate transfer body 10, and the secondary intermediate transfer body 100, and the transfer of the toner image is easily performed. Let Here, the transfer from the latent image carrier 1 to the primary intermediate transfer body 10 employs an electrostatic transfer method. However, by increasing the surface roughness Rz of the primary intermediate transfer body 10, Transfer at a low voltage becomes possible. Further, since the surface roughness Rz of the recording medium P to which the toner image is finally transferred is about 20 to 40 μm, the surface roughness Rz of the secondary intermediate transfer body 100 is set to a value smaller than this. Constitute.
[0016]
The recording medium P, on which the toner image has been transferred at the transfer nip portion between the primary intermediate transfer member 10 and the secondary intermediate transfer member 100, is conveyed to the belt of the secondary intermediate transfer member 100, is separated in curvature at the roller 110, and is fixed. Sent to the means 50. In FIG. 1, the fixing unit 50 includes a pair of fixing rollers 50A and 50B. However, the fixing member is not limited to this, and may use a belt. The fixing roller pair 50A, 50B is a roller having a heater inside and a silicone rubber layer provided on a cored bar. In addition to silicone rubber, a resin having good releasability such as Teflon, rubber, or the like may be used.
In the above-described configuration, it is desirable that the material of the fixing member of the fixing unit 50 has the same surface characteristics whether it is a roller or a belt. This is because the fixability of the toner image transferred to both sides of the recording medium P can be obtained equally on both sides, and a high-quality double-sided image can be provided.
The temperature of the fixing roller pair 50A, 50B is controlled at 160 to 200 ° C., and the pressure is controlled at ²⁰ to 100 N / cm ² . While the recording medium P is conveyed by the fixing roller pair 50A, 50B, the toner on the surface is heated and melted, and is fixed on the recording medium P by pressure.
[0017]
Hereinafter, an image forming operation of the image forming apparatus of the present invention will be described.
First, an image is formed by the latent image carrier 1. By the operation of the exposure device 4, the light from the LD light source (not shown) passes through optical components (not shown), and the latent image carrier 1 is charged uniformly by the charging device 3. It reaches the body and forms a latent image corresponding to the written information (information corresponding to the color).
The latent image on the latent image carrier 1 is developed by the developing device 5, and a visible image with toner is formed and held on the surface of the latent image carrier 1. This toner image is transferred by the primary transfer means 20 onto the surface of the primary intermediate transfer body 10 which moves in synchronization with the latent image carrier 1. In the present embodiment, the polarity of the toner formed on the latent image carrier 1 is negative. By applying a positive charge to the primary transfer unit 20, the toner formed on the latent image carrier 1 is transferred to the primary intermediate transfer body 10.
The remaining toner on the surface of the latent image carrier 1 is cleaned by the cleaning device 2 and the charge is removed by the charge removing device L to prepare for the next image forming cycle.
[0018]
The primary intermediate transfer member 10 carries the toner image transferred on the surface, and moves in the direction of the arrow. A latent image corresponding to another color is written on the latent image carrier 1 indicated by b, and is developed with a toner of the corresponding color to become a visible image. This image is superimposed on the visible image of the color before being already carried on the primary intermediate transfer body 10, and by repeating this operation for four colors, four colors are finally superimposed.
At this time, the secondary intermediate transfer member 100 is synchronously moving in the direction of the arrow, and the toner image formed on the surface of the primary intermediate transfer member 10 is transferred between the primary intermediate transfer member 10 and the secondary intermediate transfer member 100. In the nip portion, the toner image is transferred onto the surface of the secondary intermediate transfer member 100 by applying heat and pressure. At this time, the heating conditions of the transfer unit A11 and the transfer unit B30 are in a temperature range from the glass transition point temperature to the softening point temperature of the toner to be used, and the pressurizing condition is ² to 10 N / cm ² .
[0019]
When the primary intermediate transfer member 10 moves to a predetermined position, a toner image to be formed on another surface of the recording medium is formed again by the latent image carrier 1 in the above-described process, and Is started.
When the paper feed roller 27 rotates counterclockwise, the uppermost recording medium P in the paper feed device 26 is pulled out and conveyed to the registration roller pair 28. The toner image on the surface of the primary intermediate transfer body 10 is transferred to one surface of the recording medium P sent between the primary intermediate transfer body 10 and the secondary intermediate transfer body 100 via the registration roller pair 28 by applying heat and pressure. Is done. Further, the toner image on the surface of the secondary intermediate transfer member 100 is transferred to the other surface of the recording medium P by applying heat and pressure. The transfer conditions at this time are the same as those for the transfer from the primary intermediate transfer member 10 to the secondary intermediate transfer member 100 described above, and the toner is heated in a temperature range from the glass transition point temperature to the softening point temperature. The pressure is set to Ｎ10 N / cm ² .
[0020]
The recording medium P on which the toner images have been transferred on both surfaces in the above steps is sent upward, is separated in curvature at the roller 110, and is fused and fixed by the fixing roller pair 50A, 50B of the fixing means 50. Then, the sheet is discharged to a sheet discharge section 40 on the upper portion of the main body frame by a sheet discharge roller pair 32 via a guide pair 31.
Here, the lower surface of the sheet discharging unit 40 is the surface of the double-sided image that is transferred to the recording medium P later, that is, the surface that is directly transferred from the primary intermediate transfer body 10 to the recording medium P. In order to align the pages in the paper discharge unit 40, an image for the second page is prepared first, the toner image is held on the secondary intermediate transfer member 100, and The image of the page may be directly transferred from the primary intermediate transfer body 10 to the recording medium P.
Further, in this case, the image transferred from the primary intermediate transfer body 10 to the recording medium P is a normal image on the surface of the latent image carrier 1, and the toner image transferred from the secondary intermediate transfer body 100 to the recording medium P is The latent image carrier 1 is exposed to a reverse image (mirror image) on the surface.
Such image forming order for page alignment can be realized by a known technique for storing image data in a memory, and exposure for switching between a normal image and a reverse image (mirror image) can be realized by a known image processing technique.
[0021]
After transferring the toner image on the surface of the secondary intermediate transfer member 100 to the recording medium P, the cleaning device 250 removes unnecessary toner remaining on the surface of the secondary intermediate transfer member 100. The cleaning device 250 shown in FIG. 1 has a structure that can swing about a fulcrum 250D and can come into contact with and separate from the surface of the secondary intermediate transfer member 100. Before the transfer to the recording medium P, the secondary intermediate transfer member 100 is separated when the toner image is carried, and when cleaning is necessary after the transfer, the secondary intermediate transfer member 100 is swung counterclockwise in FIG. The toner transferred to the roller 250A is removed by the blade 250B, and is stored in a storage unit (not shown) via the toner recovery unit 250C.
The cleaning device 25 provided on the primary intermediate transfer body 10 also cleans the surface of the primary intermediate transfer body 10 after the transfer by the same operation.
[0022]
In the case of forming an image on only one side, two types of image forming methods can be performed. However, more simply, the step of transferring the toner to the secondary intermediate transfer member 100 is omitted, and A method of transferring the image to the recording medium P can be used.
The toner image formed on the surface of the latent image carrier 1 is transferred to the recording medium P while being transferred to the primary intermediate transfer body 10. Here, the recording medium P is conveyed between the primary intermediate transfer member 10 and the secondary intermediate transfer member 100 in synchronization with the toner image formed on the primary intermediate transfer member 10 for synchronization. The toner image is transferred from the primary intermediate transfer member 10 to the recording medium P by heating and pressing of the unit A11 and the transfer unit B30.
The recording medium P moves together with the secondary intermediate transfer member 100, is curvature-separated at the roller 110, and the toner image is fused and fixed by the fixing roller pair 50 </ b> A, 50 </ b> B of the fixing unit 50. Thereafter, the paper is discharged in the direction of arrow A via the guide pair 31 and the paper discharge roller pair 32, and is placed on the paper discharge unit 40 with the image surface down.
[0023]
In the above-described embodiment, color image formation using toners of a plurality of colors has been described. However, the technical idea of the present invention can be applied to image formation of a single color.
[0024]
【The invention's effect】
As described above, according to the present invention, the transfer step a of transferring the first visualized image carried by the primary intermediate transfer body to the secondary intermediate transfer body, and the second visualized image carried by the primary intermediate transfer body And a transfer step (b) of simultaneously transferring the first visible image carried by the secondary intermediate transfer member to both surfaces of the recording medium by applying heat and pressure, thereby obtaining toner particles as seen in the electrostatic transfer method. It is possible to provide an image forming method for forming a high-quality image without image deterioration such as dust and blemishes. In particular, the heating conditions in the transfer steps a and b are set to a temperature range from the glass transition point temperature to the softening point temperature of the toner to be used, so that the energy saving effect is excellent, and the latent image bearing member and the image around the latent image bearing member are excellent. Thermal damage to the forming component can also be reduced.
Further, the surface roughness Rz of each member of the latent image carrier, the primary intermediate transfer member, and the secondary intermediate transfer member is configured to increase in the order of notation, and the surface roughness Rz of the secondary intermediate transfer member is increased. By making Rz smaller than the surface roughness of the recording medium to be used, it is possible to provide an image forming apparatus capable of performing good transfer even in the above temperature range.
[Brief description of the drawings]
FIG. 1 is a central sectional view of an image forming apparatus according to the present invention.
[Explanation of symbols]
1 Latent image carrier 2 Cleaning device (for latent image carrier)
3 charging device 4 exposure device 5 developing device 10 primary intermediate transfer member (first image carrier)
11 Transfer Means A
12, 13, 14 roller (supporting member)
20 primary transfer means 25 cleaning device (for primary intermediate transfer member)
26 sheet feeding device 28 registration roller pair 29 transport guide 30 transfer means B
40 sheet discharging unit 50 fixing unit 50A, B fixing roller pair 100 secondary intermediate transfer member (second image carrier)
111, 112, 113 Roller (support member)
250 Cleaning device (for secondary intermediate transfer member)
P Recording medium

Claims (10)

A first transfer step of transferring the first visualized image to a second image carrier abutting the first image carrier carrying the first visualized image by applying heat and pressure,
Subsequently, the first image carrier carries a second visible image, a second visible image carried by the first image carrier, and a first visible image carried by the second image carrier. A second transfer step of simultaneously transferring the image to both sides of the recording medium by applying heat and pressure,
A fixing step of fusing and fixing the first visualized image and the second visualized image on the recording medium on the recording medium. The image forming method according to claim 1,
The temperature applied to the first image carrier in the first transfer step and the temperature applied to the second image carrier in the second transfer step are the glass transition points of the toner used for visual image formation. An image forming method, wherein the temperature is controlled within a range from a temperature to a softening point. The image forming method according to claim 1, wherein
The toner is used in a plurality of colors corresponding to the formation of a color image, and the toner of the plurality of colors has a difference of 7 ° C. between one of a difference between glass transition temperatures and a difference between softening points. An image forming method. A first image carrier that carries a visible image formed based on the image information,
A second image carrier that abuts on the first image carrier and transfers and carries a visible image carried by the first image carrier;
The visualized image carried by the first image carrier is transferred to the second image carrier, or the visualized image carried by the first image carrier and / or the second image carrier is transferred to the first image carrier. Transfer means A and transfer means B for transferring to a recording medium conveyed to a contact portion between the image carrier and the second image carrier,
An image forming apparatus having at least a fixing unit for melting and fixing a visible image on a recording medium,
The image forming apparatus, wherein the transfer unit A and the second transfer unit B are transfer units that apply heat and pressure. The image forming apparatus according to claim 4, wherein
The temperature applied from the transfer unit A to the first image carrier and the temperature applied from the transfer unit B to the second image carrier are the glass transition point temperatures of the toner used for visual image formation. An image forming apparatus characterized in that the temperature is controlled within the range of the softening point temperature or lower. The image forming apparatus according to claim 4, wherein
The pressure applied from the transfer unit A to the first image carrier and the pressure applied from the transfer unit B to the second image carrier are ² to 10 N / cm ^2. Image forming apparatus. The image forming apparatus according to claim 4, wherein
The image forming apparatus further includes a latent image carrier for carrying a latent image,
Charging means for uniformly charging the latent image carrier surface,
Exposure means for irradiating the latent image carrier surface with exposure light based on image information to form a latent image,
A developing device for visualizing the latent image formed on the surface of the latent image carrier,
Primary transfer means for transferring the visible image on the latent image carrier to the first image carrier,
The image forming apparatus according to claim 1, wherein the first image carrier is a primary intermediate transfer member, and the second image carrier is a secondary intermediate transfer member. The image forming apparatus according to claim 7,
The surface roughness Rz of each member of the latent image carrier, the primary intermediate transfer member, and the secondary intermediate transfer member is configured to be larger in the order of notation, and the surface roughness Rz of the member of the secondary intermediate transfer member is An image forming apparatus, wherein Rz is smaller than surface roughness Rz of a recording medium to be used. The image forming apparatus according to claim 4, wherein
The image forming apparatus according to claim 1, wherein the fixing unit includes two fixing members for fixing the toner on the recording medium having similar surface characteristics. The image forming apparatus according to any one of claims 4 to 9,
The image forming apparatus, wherein the fixing member is a roller or a belt.

Images