JPH06102778A - Image forming method - Google Patents

Abstract

PURPOSE:To simplify the constitution by moving only an intermediate transfer body and attaching/detaching an image carrier to/from the intermediate transfer body and also attaching/detaching the intermediate transfer body to/from a pressure rotary body, as to an image forming method using the intermediate transfer body. CONSTITUTION:A toner image is formed on the image carrier 101, the toner image is transferred onto the intermediate transfer body 102 shown by a broken line at a part shown by a mark A. This transfer is a primary transfer. Next, the toner image primarily transferred onto the intermediate transfer body 102 is transferred to a transfer sheet 120 which is fed in between the intermediate transfer body 102 shown by a chain line and a pressure roller 103 at the part shown by a mark B. This transfer is a secondary transfer. In the case of forming a multicolor image, a yellow developing device 110Y, a magenta developing device 110M, a cyan developing device 110C and a black developing device 110B are installed around the image carrier 101, and the primary transfer is selectively and successively performed on the intermediate transfer body 102, and after the full color toner image is formed, the secondary transfer is performed on the transfer sheet 120.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a toner image on an image bearing member which is rotationally driven, and primarily transfers the toner image onto an intermediate transfer member which is pressed against the image bearing member while being rotationally driven. The present invention relates to an image forming method for secondarily transferring an image onto a recording medium pressed against an intermediate transfer member by a pressure rotating member.

[0002]

2. Description of the Related Art A conventional image forming method using an electronic copying method, which is adopted in an analog copying machine, a digital copying machine, a laser printer, a facsimile, etc., generally directly copies a toner image formed on an image carrier. Transfer to a recording medium,
It is configured to fix this. On the other hand, an image forming method of the type described at the beginning is proposed in which the toner image on the image carrier is temporarily transferred to an intermediate transfer member and the toner image is secondarily transferred to a recording medium (for example, a special method). Kosho 4
6-41679, JP-A-59-17572, etc.).

[0003]

In carrying out such an image forming method, it is desirable to support the image carrier and the intermediate transfer member, and the intermediate transfer member and the pressure rotating member so that they can come into contact with and separate from each other. According to this structure, the image carrier and the intermediate transfer member, and the intermediate transfer member and the pressure rotator can be separated from each other, for example, during standby other than during the image forming operation.
As a result, it is possible to reduce the load applied to the surfaces of the image bearing member, the intermediate transfer member, and the pressure rotating member, and to extend the life of these members, and also to reduce the load applied to the drive shaft of each of these elements.

Further, toner images of different colors are sequentially formed on the image carrier, and the toner images are primary-transferred one by one on the intermediate transfer member,
When performing an image forming method of superimposing a multicolor toner image on the intermediate transfer member and then secondarily transferring the toner images collectively onto a recording medium, the intermediate transfer member and the pressure rotating member are pressed against each other during the primary transfer. The toner image on the intermediate transfer member is transferred to the pressure rotating member to stain the pressure rotating member with toner, or the image carrier and the intermediate transfer member are pressed against each other during the secondary transfer. If so, the toner image on the intermediate transfer member may be transferred onto the image carrier.Therefore, the image carrier, the intermediate transfer member, and the pressure rotating member are supported so that they can come into contact with and separate from each other. It is advantageous to separate the pressure rotating member and the pressure rotating member, and to separate the intermediate transfer member and the image bearing member from each other during the secondary transfer.

However, as described above, in order to make the image carrier and the intermediate transfer member contactable and separable, and to make the intermediate transfer member and the pressure rotator contactable and separable, these three elements or two elements are required. The elements must be movably supported and each element must be operated by a complicated contact / separation mechanism, which complicates the configuration and increases the cost of the image forming apparatus.

A first object of the present invention is to provide an image forming method using an intermediate transfer member, which eliminates the above-mentioned inconveniences, and which has a simple structure and which can form an image carrier and an intermediate transfer member, and an intermediate transfer member and a pressure rotating member. An object of the present invention is to provide an image forming method capable of contact and separation.

On the other hand, as a method of secondarily transferring the toner image on the intermediate transfer member onto the recording medium, the toner image on the intermediate transfer member is heated by a heating means and melted to be secondarily transferred onto the recording medium. The method of carrying out, a method of secondarily electrostatically transferring the toner image on the intermediate transfer member to a recording medium, and thermally fixing the toner image on the recording medium by a fixing device, or a method using these in combination is considered. No matter which method is adopted, since the heating means and the fixing device are used, the image carrier may be heated by these and the temperature thereof may rise. The image carrier is composed of, for example, a photoconductor that is charged to a predetermined polarity and an electrostatic latent image is formed by image exposure. However, when the temperature of the image carrier becomes excessively high, its charging characteristic deteriorates. To do. In addition, the toner is fused to the heated image carrier, and the image finally formed on the recording medium is disturbed.

In Japanese Utility Model Application Laid-Open No. 56-7945, the temperature is maintained so that the surface temperature at the primary transfer portion for primary transfer of the image on the image carrier to the intermediate transfer member does not exceed the melting point of the toner. However, since the image carrier and the intermediate transfer member are constantly in pressure contact with each other at the primary transfer position, heat is always supplied from the intermediate transfer member to the image carrier, and the above-mentioned problems are completely eliminated. It cannot be resolved.

Further, Japanese Patent Laid-Open No. 59-99472 discloses that
There is disclosed a configuration in which a charge erasing lamp is used to uniformly erase the electric charges of an image carrier made of a photoconductor to prevent the toner from being fused to the surface of the image carrier. The heat problem cannot be solved.

A second object of the present invention is to provide an image forming method using an intermediate transfer member, which is capable of preventing the image carrier from being excessively heated by a simple structure. It is in.

By the way, also in the image forming method in which the primary transfer and the secondary transfer are carried out by using the intermediate transfer member, the toner image on the image carrier is first transferred to the intermediate transfer member and then remains on the image carrier. Although the toner is removed by a cleaning device to clean the surface of the image bearing member, the number of operations is very large, and the burden on the cleaning device is inevitably large. Particularly, when the toner images of a plurality of colors are sequentially formed on the image carrier and an image forming operation for obtaining a color image on the recording medium is performed, the cleaning device has a longer usage time than a case of obtaining a single color image, A heavy burden is placed on the cleaning device.

Further, when the recording medium is supplied to the secondary transfer portion in order to secondarily transfer the toner image on the intermediate transfer member, the recording medium causes a conveyance trouble and the recording medium is not conveyed to the secondary transfer portion. There is. When such a problem occurs, conventionally, the image forming operation is immediately stopped, the troubled recording medium is removed, and then the toner image already formed on the surface of the image carrier is cleaned and removed by the cleaning device. However, the image forming operation is continued. That is, the toner image on the image carrier that should have been transferred to the recording medium in which the trouble has occurred is removed by a cleaning device, and the image forming operation is continued after the state of the image forming device is returned to the initial state. is there.

However, when the toner image on the image carrier, which is not used as an output image, is cleaned by the cleaning device every time the recording medium has such a conveyance trouble,
The usage time of the cleaning device increases more and more. Therefore, the load on the cleaning device is further increased, the cleaning function of the cleaning device is deteriorated early, and the life of the cleaning device may be shortened.

In particular, recently, as a toner for forming a toner image, a toner having a small particle diameter tends to be used in order to improve the image quality. When such a fine particle toner is used,
Since the cleaning efficiency of the toner remaining on the image carrier is lowered, the above-mentioned problems are likely to occur.

A third object of the present invention is to reduce the load of the cleaning device for cleaning the surface of the image carrier after the primary transfer of the toner image in the image forming method using the intermediate transfer member,
An object of the present invention is to provide an image forming method capable of maintaining a high cleaning function for a long period of time and achieving a long life.

By the way, in the image forming method using the intermediate transfer member, as one of the methods for secondarily transferring the toner image on the intermediate transfer member to the recording medium, as described above, the toner image on the intermediate transfer member is heated. A method is known in which the toner is melted by means of the above method and the melted toner image is secondarily transferred onto a recording medium.

On the other hand, as the recording medium, a plain paper sheet or a sheet made of resin is used. The latter resin sheet is used to secondarily transfer the molten toner image on the intermediate transfer member. For this reason, the toner image on the intermediate transfer member must be heated to a higher temperature than in the case where the fused toner image is secondarily transferred to plain paper. However, in the conventional image forming method of this type, the thermal energy to be applied to the toner image on the intermediate transfer member is set to a constant magnitude regardless of the material of the recording medium. There is a possibility that the transfer efficiency of the toner image on the recording medium may be reduced, or the toner image may not be easily fixed on the recording medium, and the image quality of the final image on the recording medium may be degraded.

A fourth object of the present invention is to provide an image forming method using an intermediate transfer member, which can obtain a high quality image even when the recording medium is made of resin. .

As described above, various materials are used as the recording medium, but in addition, recording media having various thicknesses are used. However, in the conventional image forming method of this type, when the toner image is secondarily transferred from the intermediate transfer body to the recording medium, the pressure contact force between the intermediate transfer body and the pressure rotating body is always kept constant. When the thickness of the recording medium is particularly thick, it becomes impossible to pass the recording medium between the intermediate transfer body and the pressure rotating body, and the pressure applied to the recording medium by the intermediate transfer body and the pressure rotating body is reduced. There is a possibility that the image quality becomes unsuitable, the secondary transfer of the toner image and the fixing property of the toner image deteriorate, and the image quality of the final image on the recording medium deteriorates.

A fifth object of the present invention is to provide an image forming method using an intermediate transfer member, which can form a high quality final image on the recording medium regardless of the thickness and material of the recording medium. To do.

[0021]

In order to achieve the first object of the present invention, a toner image is formed on an image carrier which is rotationally driven, and the toner image is formed on the image carrier while being rotationally driven. In an image forming method of primary transfer to a pressure-contacted intermediate transfer member, and secondarily transferring the toner image onto a recording medium pressure-contacted to the intermediate transfer member by a pressure rotating member, the image carrier and the pressure rotating member are: The intermediate transfer member is rotatably but immovably supported, and the intermediate transfer member is rotatably and movably supported so as to come into contact with and separate from the image carrier and the pressure rotator, and at least the primary transfer member is supported. An image forming method is proposed in which an intermediate transfer body is brought into pressure contact with an image carrier at the time of transfer, and at least at the time of the secondary transfer, the intermediate transfer body is brought into pressure contact with a pressure rotating body via the recording medium.

At this time, it is desirable that the cleaning device for cleaning the surface of the intermediate transfer body after the toner image on the intermediate transfer body is secondarily transferred to the recording medium is moved together with the intermediate transfer body. .

In order to achieve the second object of the present invention, an intermediate transfer member, in which a toner image is formed on an image bearing member which is rotationally driven, and the toner image is pressed against the image bearing member while being rotationally driven. In the image forming method, the toner image is primarily transferred onto the intermediate transfer body and the toner image is secondarily transferred onto the recording medium pressed against the intermediate transfer body by the pressure rotating body. An image forming method is proposed, in which the toner image on the image carrier is primarily transferred to the intermediate transfer member located above the image carrier.

In order to achieve the second object of the present invention, a toner image is formed on an image bearing member which is rotationally driven, and the toner image is applied to an intermediate transfer member which is rotationally driven and pressed against the image bearing member. In the image forming method, the toner of the toner image is primary-transferred, the toner of the toner image is melted by a heating unit, and the melted toner image is secondarily transferred to a recording medium pressed against the intermediate transfer member by a pressure rotating member. The image carrier and the image carrier so that they can be brought into contact with and separated from each other, and at least the intermediate transfer member and the image carrier are brought into pressure contact with each other at the time of the primary transfer. An image forming method is proposed in which the heating means is controlled so as not to operate.

Similarly, in order to achieve the second object,
A toner image is formed on an image carrier that is rotationally driven, the toner image is primarily transferred to an intermediate transfer member that is pressed against the image carrier while being rotationally driven, and the toner of the toner image is melted by a heating unit. In the image forming method for secondarily transferring the melted toner image onto the recording medium pressed against the intermediate transfer member by the pressure rotating member, the surface temperature of the intermediate transfer member is detected by the temperature detecting means, and the surface of the intermediate transfer member is detected. An image forming method is proposed in which the image forming operation is interrupted when the temperature detecting unit detects that the temperature has reached a predetermined value or higher.

In the same manner, in order to achieve the second object, a toner image is formed on an image carrier which is rotationally driven, and the toner image is primarily formed on an intermediate transfer member which is rotationally driven and pressed against the image carrier. When the transfer trouble of the recording medium is detected in the image forming method in which the toner image is transferred and the toner image is secondarily transferred to the recording medium pressed against the intermediate transfer body by the pressure rotating body, the rotation of the image carrier is stopped. An image forming method is proposed in which the rotation is continued without being performed.

Further, similarly, in order to achieve the second object, a toner image is formed on an image carrier which is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member which is rotationally driven and pressed against the image carrier. In the image forming method in which the toner image is transferred, and the toner image is secondarily transferred to the recording medium pressed against the intermediate transfer body by the pressure rotating body, the rotation of the intermediate transfer body is stopped when the conveyance trouble of the recording medium is detected. An image forming method is proposed in which the rotation is continued without being performed.

In order to achieve the third object, the present invention forms an toner image on an image carrier which is rotationally driven, and the toner image is brought into pressure contact with the image carrier while being rotationally driven. In the image forming method in which the toner image is primarily transferred onto the recording medium and the toner image is secondarily transferred onto the recording medium that is pressed against the intermediate transfer member by the pressure rotating member, the intermediate transfer member and the image bearing member are supported so that they can be separated from each other. At the same time, the intermediate transfer body and the pressure rotator are supported so that they can be brought into contact with and separated from each other, the intermediate transfer body and the image carrier are brought into pressure contact with each other at least during the primary transfer, and at least during the secondary transfer, the intermediate transfer body and the image bearing body are applied. The pressure rotator and the recording medium are brought into pressure contact with each other, and it is detected whether or not the recording medium supplied to the secondary transfer portion where the secondary transfer is performed causes a conveyance trouble and the image carrier. The bodies are separated from each other There later, and the intermediate transfer member and the pressure rotating body is proposed an image forming method carried out during the before welding.

Further, according to the present invention, in order to achieve the fourth object, a toner image is formed on an image carrier which is rotationally driven,
The toner image is primarily transferred to an intermediate transfer body that is in pressure contact with the image carrier while being rotationally driven, the toner of the toner image is melted by a heating means, and the melted toner image is transferred by the pressure rotating body to the intermediate transfer body. In the image forming method of secondary transfer onto the recording medium pressed against the intermediate transfer member, when the recording medium is made of resin, the intermediate transfer member is rotated a plurality of times while the heating unit is operating, and then the intermediate transfer member is rotated. An image forming method for secondarily transferring the toner image of No. 2 to a recording medium is proposed.

In order to achieve the fifth object of the present invention, an intermediate transfer member, in which a toner image is formed on an image bearing member which is rotationally driven, and the toner image is pressed against the image bearing member while being rotationally driven. In the image forming method of secondarily transferring the toner image to the recording medium pressed against the intermediate transfer member by the pressure rotating member, the toner image is transferred to the intermediate transfer member depending on the thickness and the material of the recording medium. An image forming method is proposed in which the pressure with which the pressure rotating body is pressed is changed.

[0031]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an example of an image forming apparatus for carrying out the image forming method according to the present invention. This apparatus includes a photosensitive drum 101, which is an example of the constitution of an image carrier, and an intermediate member formed in a drum shape. It has a transfer member 102 and a pressure rotating member configured as a pressure roller 103. In this example, the photosensitive drum 101 is located at the lowermost position, the intermediate transfer member 102 is located above it, and the pressure roller 103 is located above it. The intermediate transfer member 102 operates from the retracted position indicated by the solid line to the position indicated by the broken line or the position indicated by the alternate long and short dash line, and can be pressed against the photosensitive drum 101 or the pressure roller 103. The contact / separation operation will be described later.

The photoconductor drum 101 exemplified here is a drum-shaped organic photoconductor having relatively high pressure resistance and heat resistance, and the pressure roller 103 is a rigid roller formed of, for example, aluminum. The outer surface thereof may be covered with a compression resistant resin. Instead of such a drum-shaped pressure rotating member, an image bearing member, or an intermediate transfer member, a belt-shaped member may be used.

As will be described later in detail, a toner image is formed on the photosensitive drum 101, and this toner image is transferred at the portion indicated by the symbol A onto the intermediate transfer member 102 occupying the position shown by the broken line. It This transfer is primary transfer, and henceforth, this part A is called a primary transfer part. The toner image primarily transferred onto the intermediate transfer member 102 is an example of the transfer medium fed between the intermediate transfer member 102 and the pressure roller 103, which occupy the position indicated by the alternate long and short dash line, as described later. Is transferred to the transfer paper 120 at the portion indicated by reference numeral B. This is the secondary transfer.
Will be referred to as a secondary transfer portion.

Although the present invention can be applied to an image forming method for forming a monochromatic image exclusively, the image forming apparatus shown in FIG. 1 is constructed so as to form a multicolor image as well. The details of the configuration shown in FIG. 1 will be clarified while explaining the operation thereof.

FIG. 2 is a time chart showing the basic operation thereof. First, when the operator presses the print key of the operation unit which is not shown in FIG. 1, the main motor of the apparatus starts rotating (see FIG. 2). (1), (2)). When the CPU recognizes that the main motor has steadily rotated, the charging charger (scorotron charger) 104 provided around the photosensitive drum 101 starts to operate ((3) in FIG. 2). Further, as shown in (25) of FIG.
An elevating motor (not shown) for raising and lowering the intermediate transfer body 102 is operated, whereby the intermediate transfer body 102, which has been in the retracted position shown by the solid line in FIG. 1 until then, moves to the position shown by the broken line in FIG. Then, the intermediate transfer body 102 is brought into contact with the photosensitive drum 101 under pressure as shown in FIG.

The pressure contact at this time is shown as "primary pressure contact" in (27) of FIG. 2. At the time of this pressure contact, a straight line having an inclination in the timing chart of FIG. It shows that the transfer body 102 is initially separated from the photoconductor drum 101, and that it takes a certain time to complete the pressure contact between the two. Further, even when they are separated from each other, the fact that they fall by a straight line with an inclination means that it takes a certain time to completely separate from the state where the photosensitive drum 101 and the intermediate transfer member 102 are in pressure contact with each other. I mean.

When the photoconductor drum 101 and the intermediate transfer member 102 are pressed against each other as described above, the photoconductor motor clutch provided between the photoconductor drum 101 and the main motor is turned on to rotate the main motor. Is the photoconductor drum 1
01, the photosensitive drum 101 starts rotating in the clockwise direction indicated by the arrow in FIG. Regarding this clutch, it is shown as "photoconductor MC" in (4) of FIG.

Similarly, an intermediate transfer body motor clutch (intermediate MC) is also provided between the intermediate transfer body 102 and the main motor, and another pressure roller is also provided between the pressure roller 103 and the main motor. Motor clutches (pressurized MC) are provided, and these clutches are shown as (5) and (6) in FIG.
As shown in FIG. 3, the photoconductor motor clutch (photoconductor MC) is turned on at the same time, and the intermediate transfer body 102 and the pressure roller 103 start rotating in the directions indicated by the arrows in FIG. At this time, the linear velocities of these peripheral surfaces are the same.

The photosensitive drum 101 and the intermediate transfer member 1
After the rotation of 02, the intermediate transfer member motor clutch (intermediate MC) is disengaged when the photosensitive drum 101 and the intermediate transfer member 102 are in pressure contact with each other in order to match the linear velocities of the peripheral surfaces of the two. You may make it rotate along with the rotation of the photosensitive drum 101.

As described above, the photosensitive drum 101 rotates clockwise in FIG. 1, but at this time, the charger 104
Has already started its operation, the photosensitive drum 101
By the corona discharge of this charger 104,
It is uniformly charged to a predetermined polarity.

The photoconductor drum 101 thus charged.
The surface of is exposed and scanned by a laser beam 106 modulated based on an image signal by a laser optical system 105, and an electrostatic latent image for a first color, in this example, a yellow image (in this example, yellow) is formed on the surface of the photosensitive drum 101. Yellow latent image) is formed. This is shown as "Y latent image formation" in (13) of FIG.

A laser optical system 105 for image-exposing the surface of the photoconductor drum 101 after charging with a laser beam 106 is composed of a semiconductor laser, a polygon mirror, an fθ lens, etc., which are not shown, and a laser modulation circuit responds to an image signal. Control the emission of the semiconductor laser.

On the other hand, a developing device 110 is disposed around the photosensitive drum 101 as shown in FIG. 1. The developing device 110 illustrated here contains yellow, magenta, cyan and black toners, respectively. Yellow developer 1
10Y, magenta developing device 110M, cyan developing device 110
C and a black developing device 110B are provided, and these developing devices are arranged along the moving direction of the photosensitive drum 101. These developing devices are selectively operated and used. Although the developing device 110 shown in FIG. 1 is a dry type developing device, a wet type developing device using a developing solution may be used instead.

As the toner used in each developing unit, it is preferable to use a toner having a particle size of 5 μm or less in order to improve dot reproducibility, and it is desirable to use a toner having a narrow particle size distribution produced by a polymerization method.

The yellow latent image formed on the photosensitive drum 101 which is rotationally driven as described above is visualized as a toner image by the yellow toner when the yellow latent image passes through the yellow developing device 110Y. At this time, the other developing devices 110M, 110C, 110B do not perform the developing operation. The operation at this time is shown in (14) of FIG.
It is shown as.

With the rotation of the photosensitive drum 101 and the intermediate transfer member 102, the photosensitive drum portion on which the yellow toner image is formed as described above is the primary transfer in which the intermediate transfer member 102 and the photosensitive drum 101 are in pressure contact with each other. The area A is reached, and at this time, the yellow toner image on the photosensitive drum 101 is primarily transferred onto the intermediate transfer body 102. The toner image on the photosensitive drum 101 is primarily transferred onto the intermediate transfer member 102 that is pressed against the photosensitive drum 101 while being rotationally driven.

Photoreceptor drum 10 that has passed primary transfer portion A
The toner remaining on the surface of No. 1 is the photosensitive drum 101.
Is removed by a cleaning device 111 arranged around the surface of the substrate, the surface is cleaned, and a static eliminating device (not shown) removes the static electricity. The primary transfer of the yellow toner image is shown as (primary transfer) and “Y primary transfer” in (21) of FIG.
The cleaning of 01 is shown as "photoconductor cleaning" in (22) of FIG.

During such an operation, the intermediate transfer member 102 is rotating, and the yellow toner image primarily transferred onto this surface is transferred to the secondary transfer portion B and the cleaning device 112 for cleaning the intermediate transfer member 102. Although it passes, at this time, (28) in FIG. 2 is shown as “secondary pressure contact”, which means the pressure contact between the intermediate transfer member 102 and the pressure roller 103.
As can be seen from 4) as "intermediate cleaning", which means the cleaning operation of the intermediate transfer body 102, the pressure roller 103 is not in contact with the intermediate transfer body 102, and the cleaning device 112 does not operate. Moreover, since the cleaning roller 112a is separated from the intermediate transfer body 102, there is no possibility that the yellow toner image on the intermediate transfer body 102 is disturbed.

As described above, the surface of the photosensitive drum 101, which has been cleaned by the cleaning device 111 and subjected to the static elimination function by the static elimination device, is uniformly charged again by the charging charger 104 ((3) in FIG. 2). A magenta latent image for a magenta image is formed on the surface by the laser 106 from the laser optical system 105 (“M latent image formation” in FIG. 2 (15)). Subsequently, this magenta latent image is visualized as a magenta toner image by the magenta developing device 110M selected in place of the yellow developing device 110Y (“M development” in FIG. 2 (16)). This magenta toner image is also transferred to the primary transfer portion A as the photosensitive drum 101 rotates.
Then, the yellow toner image is superposed and primary-transferred onto the intermediate transfer member 102 (“M primary transfer” in FIG. 2 (21)). The toner remaining on the photoconductor drum 101 after this primary transfer is also cleaned by the cleaning device 111 ((22) in FIG. 2), and the surface of the drum 101 is subjected to the static elimination action.

In exactly the same manner, a cyan latent image for a cyan image and a black latent image for a black image are sequentially formed on the photosensitive drum 101 (see "C latent image formation" in FIG. 2 (17)). (19) "B latent image formation"), these latent images are sequentially visualized as toner images of the respective colors by the cyan developing device 110C and the black developing device 110B ("C development of FIG. 2 (18)"). , (20) "B development"), these toner images are primarily transferred onto the intermediate transfer member 102 in order from the top of the previously transferred toner image ("C primary transfer in FIG. 2 (21)"). And "B primary transfer"). In this way, a full-color toner image is formed on the intermediate transfer member 102.

When the arrangement state of each element such as the photosensitive drum 101, the intermediate transfer body 102, and the pressure roller 103 is changed, the start timings of the electrostatic latent image formation and the development operation are shown in FIG. It is natural that it needs to be changed from the one shown in.

When all the primary transfer is completed, the intermediate transfer member 102 is separated from the photosensitive drum 101 ((27) in FIG. 2) by the operation of the elevating motor ((25) in FIG. 2), and is indicated by the alternate long and short dash line in FIG. As shown, it moves to the pressure roller 103 side and comes into pressure contact with this pressure roller 103 (see FIG. 4). Regarding this press contact, it is shown as "secondary press contact" in (28) in FIG.

The timing at which the primary transfer portion pressure contact for separating the intermediate transfer member 102 from the photosensitive drum 101 is released is on the intermediate transfer member 102 after the primary transfer of the toner image on the photosensitive drum 101 to the intermediate transfer member 102. In the non-image area of
It is preferable that the toner image on the intermediate transfer member 102 is not disturbed.

The tip portion of the full-color toner image formed on the intermediate transfer member 102 reaches the secondary transfer portion B as the intermediate transfer member 102 rotates. The paper feed motor clutch (paper feed MC) provided between the paper feed unit 113 and the paper feed roller 114 is turned on ((8) in FIG. 2), and the paper feed roller 114 moves clockwise in FIG. Rotate. As a result, the transfer sheet 120 accommodated in the sheet feeding unit 113 is fed to the left side in FIG. 1, and as shown in FIG. 1, the pair of registration rollers 115 that stop rotating.
Be transported to.

The registration roller 115 is also connected to the main motor via a registration motor clutch (registration MC), and immediately after the main motor starts rotating as described above, as shown in (7) of FIG. The motor clutch (registration MC) is turned on, the registration rollers 115 rotate, and then this clutch is turned off.
When the leading edge of the transfer paper 120 reaches the registration roller 115, the registration roller 115 is stopped.

Subsequently, the registration motor clutch (registration MC) is turned on at the timing when the full-color toner image on the intermediate transfer member 102 and the transfer paper 120 can be aligned, and the registration roller 115 starts rotating ((7) in FIG. 2). ), The transfer paper 120 is conveyed to the secondary transfer portion B.

On the other hand, the front end of the transfer paper 120 is the secondary transfer portion B.
The intermediate transfer body 102 is pressed against the pressure roller 103 as described above, and the transfer paper 120 is pressed against each other, and the secondary transfer portion between the intermediate transfer body 102 and the pressure roller 103 is pressed. After passing B, it is conveyed to the left in FIG. Since the intermediate transfer body 102 and the pressure roller 103 are brought into pressure contact with each other in synchronization with the timing when the front end of the transfer paper 120 reaches the secondary transfer portion B between the intermediate transfer body 102 and the pressure roller 103, the intermediate transfer body 102 is pressed. It is possible to prevent the problem that the upper toner image is transferred to the pressure roller 103.

As described above, the transfer paper 120 is the secondary transfer portion B.
When it passes through, the full-color toner image on the intermediate transfer member 102 is secondarily transferred onto the transfer paper 120 ((2 in FIG. 2).
3)). In this way, the toner image on the intermediate transfer body 102 is secondarily transferred onto the transfer paper 120 pressed against the intermediate transfer body 102 by the pressure roller 103. The toner remaining on the intermediate transfer member 102 after the secondary transfer of the toner image is removed by the cleaning device 112 ((24) in FIG. 2), which will be described in detail later.

Next, the transfer paper 120 includes a conveyor belt 122 driven in the direction of the arrow and a pair of rotating paper discharge rollers 1.
The sheet is conveyed by 17 and discharged to the sheet discharge unit 119. A paper discharge motor clutch (paper discharge MC) is also provided between the conveyor belt 122 and the paper discharge roller 117 and the main motor, and the clutch is turned on immediately after the main motor starts to rotate. 122 and the discharge roller 117 are rotationally driven, and as described above, the transfer sheet 120
Is conveyed to the paper output unit 119 ((9) in FIG. 2).

When the secondary transfer is completed, the elevating motor is operated ((25) in FIG. 2), the intermediate transfer member 102 is lowered, and
The pressure roller 103 is separated from the pressure roller 103, and the pressure contact of the secondary transfer portion B is released ((28) in FIG. 2). In this way, the intermediate transfer member 102 moves to the retracted position shown by the solid line in FIG.

Here, in the "intermediate transition" shown in (26) of FIG. 2, the intermediate transfer body 102 moves from its retracted position to a position where it comes into pressure contact with the photosensitive drum 101, and the pressure roller 1
The above-mentioned timing of moving to a position where it is pressed against 03 is shown. At this time, in this timing chart, the shift to the minus side (lower side of FIG. 2) with respect to the time axis is the intermediate transfer member. 102 shows that the intermediate transfer member 102 moves toward the photoconductor drum 101 side and comes into pressure contact with the photoconductor drum 101, and is also shifted to the positive side (upper side in FIG. 2). Move to the roller 103
It shows that it is pressed against.

Further, in this example, when the intermediate transfer body 102 performs the contact / separation operation with respect to the photosensitive drum 101 or the pressure roller 103, the cleaning device 11 for the intermediate transfer body 102 is used.
2 and a heater 121 and a temperature sensor 123 described later,
As shown by a broken line and a one-dot chain line in FIG.
Works with 2.

Further, at the exit of the paper output unit 119, a paper output unit outlet sensor (not shown) is provided to transfer the transfer paper 120.
When the discharge of the transfer paper 120 is confirmed and the cleaning of the intermediate transfer body 102 is completed, the main motor, the charger, the resist MC, the discharged paper MC, the photoconductor MC, and the intermediate MC are cut off. .

A registration detection sensor 116 is arranged at a position on the front side of the registration roller 115 in the transfer paper conveyance direction, and the front end of the transfer paper 120 conveyed from the paper supply unit 113 is the sensor as described above. The sheet feeding motor clutch (sheet feeding MC) is turned off after a predetermined time (t seconds) from the detection by 116 ((10) and (8) in FIG. 2). In this way, the leading end of the registration roller 1
The transfer paper 120 in contact with 15 can be slightly curved, and when the registration roller 115 is rotated in this state to start feeding the transfer paper 120 to the secondary transfer portion B, a skew is generated in the transfer paper. Without intermediate transfer body 1
It is possible to convey the toner image on the toner image No. 02 at the right timing. The timing at which the paper feed motor clutch (paper feed MC) is turned off, that is, the time t, is the transfer paper 120.
Of course, it should be appropriately set according to the conveyance speed of.

The transfer paper 120 of the paper supply unit 113 is supplied by the rotation of the paper supply roller 114. However, the vibration during this operation adversely affects the electrostatic latent image formed on the photosensitive drum 101. If there is a possibility of giving an electrostatic latent image, it is advisable to set the operation sequence so that the transfer paper 120 is not fed at the time of forming the electrostatic latent image.

Incidentally, in the timing chart of the pressure contact of the secondary transfer portion shown in (28) of FIG. 2, what rises up with a straight line having an inclination during the pressure contact operation is the intermediate transfer member 10.
No. 2 is initially separated from the pressure roller 103, and it takes a certain time to complete the pressure contact, and even when the pressure contact is released, the line 2 descends with an inclined straight line.
This means that it takes a certain time for the intermediate transfer body 102 and the pressure roller 103 to completely separate from the pressed state.

Attention should be paid here to the intermediate transfer member 10.
2 at the timing of starting the secondary transfer of the toner image onto the transfer paper 120, the pressure roller 103 and the intermediate transfer member 102.
And that the pressure contact of the secondary transfer portion must be completely completed, and that the photosensitive drum 101, the intermediate transfer member 102, and the pressure roller 103 are rotating at the same peripheral surface linear velocity. It has to be. From this point of view, in this example, (6) in FIG.
As shown in (23) and (28), at the start timing of the secondary transfer, the pressure MC is turned off so that the pressure roller 103 can freely rotate, and the pressure roller 103 rotates the intermediate transfer member 102. It is driven by rotating around,
The peripheral surface speeds of both are adjusted.

The above is the outline of the operation for obtaining a full-color final image on the transfer paper 120 by the image forming apparatus shown in FIG. 1. Next, the toner image on the photosensitive drum 101 is transferred to the intermediate transfer member. The method of primary transfer to 102,
A method of secondarily transferring the toner image on the intermediate transfer member 102 to the transfer paper 120 and fixing the secondarily transferred toner image will be clarified.

First, the secondary transfer method will be described. In the image forming apparatus shown in FIG. 1, the surface of the intermediate transfer member 102 is made of a material exhibiting releasability to the melted toner, for example, silicon rubber. In addition, in the vicinity of the intermediate transfer member 102, an infrared ray is provided in a region downstream of the photosensitive drum 101 and upstream of the secondary transfer portion B as viewed in the rotation direction of the intermediate transfer member 102. A heater 121 composed of a halogen lamp, a nickel-chromium alloy wire, a ribbon, or the like is arranged to face each other.

As the intermediate transfer member 102, as shown in FIG. 5, a drum base 102a made of a rigid material such as aluminum has a thickness of 500 to 5000 μm and a rubber hardness of 3.
A 0 to 80 degree elastic layer 102b, a conductive layer 102c having a thickness of 30 to 300 μm made of polyimide in which carbon black is dispersed, and a sheet made of an insulating layer 102d having a thickness of 10 to 300 μm are bonded with the elastic layer 102b inside. It is preferable to use the one. In addition, the intermediate transfer member 102
If the surface of the toner has unevenness equal to or larger than the size of the toner forming the toner image, transfer omission may occur. Therefore, for example, when the substantial minimum particle size of the toner is 5 μm, the unevenness on the surface of the intermediate transfer member is preferably 5 μm or less.

The heater 121 is turned on at the timing shown in (29) of FIG. 2, and the full-color toner image formed of the four color toners formed on the intermediate transfer member 102 as described above is transferred to the secondary transfer portion B. Before reaching, the heater 121 irradiates a heat ray to the toner image. At this time, the black toner in the full-color toner image directly absorbs the heat rays and melts, and the heat ray-transmitting chromatic color toner is indirectly heated by the heat from the intermediate transfer body 102 heated by the heater 121. The four color toners of the full-color toner image are melted and melted so as to have almost the same viscosity.

When the thus-melted full-color toner image reaches the secondary transfer portion B where the transfer paper 120 exists as the intermediate transfer member 102 rotates, at this time, the surface of the intermediate transfer member 102 is as described above. Since the toner exhibits a releasability with respect to the melted and fluidized toner, the molten toner image on the intermediate transfer body 102 is effectively transferred to the transfer paper 120. The molten toner thus transferred to the transfer paper 120 permeates the transfer paper, and thus the transfer toner image can be fixed on the transfer paper 120 at the same time as the secondary transfer of the toner image.
Therefore, the transfer paper 120 after the secondary transfer may be discharged as it is without passing through the fixing device, and the structure of the device can be simplified.

Prior to the secondary transfer of the toner image, the heater 121 supplies the toner image on the intermediate transfer member 102 with energy required for the secondary transfer and fixing of the thus transferred toner image. If the temperature of the toner at this time is too low, the temperature of the contact interface decreases when the toner comes into contact with the transfer paper 120, and the toner does not penetrate into the transfer paper and a transfer failure occurs. On the other hand, if the temperature of the toner becomes too high, the transfer paper is likely to be deformed in various shapes. For example, for a toner having a glass transition temperature of 60 ° C., it is desirable to set the temperature of the transfer paper 120 to about 60 to 120 ° C. By doing so, the toner is substantially deformed without being deformed. The image can be transferred onto a transfer paper.

As described above, in this example, the intermediate transfer member 102 is used.
The upper toner image is melted and secondarily transferred, and the heater 121 constitutes an example of a heating unit that melts the toner of the toner image on the intermediate transfer body. The toner image thus melted is secondarily transferred onto the transfer paper 120 pressed against the intermediate transfer body 102 by the pressure roller 103.

A heater is also provided inside the pressure roller 103, and this roller 103 is used as a heat roller.
3 is heated to a temperature not lower than the glass transition temperature of the toner to heat the transfer paper 120 at the time of the secondary transfer of the toner image so as to give a sufficient heat amount required for the toner,
A configuration in which a heater is provided inside the intermediate transfer member 102 can also be adopted. As described above, the heating unit that melts the toner of the toner image on the intermediate transfer member 102 can be configured in various modes.

As described above, in this example, the intermediate transfer member 10 is used.
The full-color toner image on No. 2 is heated by the heater 121 to be melted and secondarily transferred to the transfer paper 120, and the toner is fixed on the intermediate transfer member 102 instead. When the toner is melted by the heater 121, the heating temperature is lowered as compared with the case of the above-mentioned configuration, and when the toner image is secondarily transferred to the transfer paper 120,
This may not be fixed on the transfer paper. In this case, the transfer paper that has passed through the secondary transfer section B is passed through a fixing device (not shown), and the toner image is thermally fixed on the transfer paper.

Alternatively, the toner on the intermediate transfer member 102 is not melted at all, and instead, a bias voltage is applied to the pressure roller 103 to electrostatically transfer the toner image on the intermediate transfer member 102 to the transfer paper 120. The toner image may be secondarily transferred onto the transfer paper by attracting the toner to the sheet. In this case as well, the toner image on the transfer paper that has passed through the secondary transfer portion B needs to be thermally fixed by the fixing device.

Further, the toner image on the intermediate transfer member 102 may be secondarily transferred to the transfer paper 120 by using the melting of the toner and the application of the bias voltage to the pressure roller 103 together. .

When any of the secondary transfer methods is adopted, the intermediate transfer body 102 that has undergone the secondary transfer is cleaned by the cleaning device 112 as described above. In this example, the cleaning device 112 is used. When the residual toner on the intermediate transfer member 102 is cleaned by the heat roller 112a having a low surface energy, this heat roller 1a is used.
12a is brought into pressure contact with the peripheral surface of the intermediate transfer member 102, the residual toner is melted, the toner is transferred to the roller 112a side, and the intermediate transfer member 102 is cleaned.

The heat roller 112a is made of, for example, a roller body made of aluminum coated with a material having a high releasability such as Teflon.
The toner adhering to 2a is scraped off by the rubber blade 112b pressed against the roller 112a, and the scraped toner is stored in the casing 112c of the cleaning device 112.

When the toner image on the intermediate transfer member 102 is secondarily transferred to the transfer paper 120 without being melted, the intermediate transfer member 1
As the cleaning device 112 for 02, an elastic blade or a magnetic brush that is pressed against the intermediate transfer member 102,
Alternatively, an apparatus having a cleaning member such as a bias roller can be used.

Next, in order to primarily transfer the toner image on the photosensitive drum 101 to the intermediate transfer member 102, the intermediate transfer member 10
Adhesion method in which the toner image is primarily transferred onto the intermediate transfer member 102 by utilizing the adhesiveness of the surface of the second transfer member, and a bias voltage is applied to the intermediate transfer member 102 to transfer the toner on the photosensitive drum 101 to the intermediate transfer member 102. An electrostatic method in which the toner is electrostatically attracted to the surface to perform primary transfer, and a toner image of the first color formed on the photosensitive drum 101 is primarily transferred to the intermediate transfer body 102 by any of the above-described methods, and thereafter, When the color toner image is primarily transferred onto the intermediate transfer member 102, the toner image already transferred onto the intermediate transfer member 102 is heated by the heater 121 to melt the toner image, and the adhesive force on the photosensitive drum 101 is applied. A melt-adhesive method in which the toner image is primarily transferred onto the intermediate transfer member 102 and a transfer method in which these are used together are conceivable.

Although any of the above-mentioned methods may be employed to perform the primary transfer, if the surface of the intermediate transfer member 102 is made of a material having viscoelasticity such as silicone rubber as described above, the surface is kept at room temperature. The toner image on the photosensitive drum 101 can be adhesively transferred onto the intermediate transfer member 102 by utilizing this property.

When the toner image on the photosensitive drum 101 is electrostatically primary-transferred to the intermediate transfer member 102, for example, the conductive layer 102c of the intermediate transfer member 102 shown in FIG. 5 is insulated from the drum base 102a. Then, a bias voltage may be applied to the conductive layer 102c during the primary transfer of the toner image.

If the surface of the intermediate transfer member 102 has elasticity as described above, the intermediate transfer member 102 is subjected to the primary transfer.
And the photoconductor drum 101 are in close contact with each other, and a sufficient contact area and uniform pressure can be obtained between the photoconductor drum 101 and the photoconductor drum 101, so that it is possible to prevent the formation of a non-uniform gap between the two and prevent the toner from scattering. At the same time, there is no density unevenness, and a toner image excellent in resolution and dot reproducibility is formed, and
It is also possible to form on top, and thus on transfer paper.

In the above description, the toner images on the photoconductor drum 101 are sequentially primary-transferred to the intermediate transfer member 102 to form a full-color toner image on the intermediate transfer member 102. Alternatively, the full-color toner image may be transferred and transferred onto the transfer paper 120. In this case, the transfer paper 120 fed from the paper feeding unit 113 is wound around the peripheral surface of the pressure roller 103 and held by a clamper (not shown), and the toner image of the first color from the photosensitive drum 101 is held. Is primarily transferred to the intermediate transfer member 102, and then this toner image is secondarily transferred as it is to the transfer paper 120 wound around the pressure roller 103. Also in this secondary transfer, the toner of the toner image on the intermediate transfer body 102 is melted by the heater 121 and transferred to the transfer paper 120, or the toner image on the intermediate transfer body 102 is electrostatically transferred onto the transfer paper 120. Transcribe. Next, for the toner images of the second and subsequent colors,
Every time this is primary-transferred onto the intermediate transfer member 102, the transfer paper 120 is secondarily transferred, and finally the toner image of each color is transferred onto the transfer paper 1.
20 to form a full color toner image. Then, the transfer paper 120 is peeled off from the pressure roller 103 and is discharged to the paper discharge unit 119.

When the toner images are superposed and primary-transferred onto the intermediate transfer member 102 and then secondary-transferred collectively onto the transfer paper 120, the transfer paper 120 is clamped to the pressure roller 103, at that time. The transfer paper 120 may be preheated, and the toner image on the intermediate transfer body 102 may be secondarily transferred onto the transfer paper 120. In this case, the operation timing of the transfer system of the transfer paper 120 is different from that shown in FIG.

As described above, it is appropriately selected whether the toner images are sequentially transferred and transferred onto the transfer paper or the full-color toner image on the intermediate transfer member 102 is collectively transferred onto the transfer paper, and the above-mentioned primary transfer method is appropriately selected. The image forming operation can be performed in combination, and an example of the combination is as follows.

Adhesion of first color, adhesion of second color or later, color superposition on intermediate transfer body, first color electrostatic, electrostatics of second color or later, color superposition on intermediate transfer body first color adhesive, electrostatics of second color or later, color on intermediate transfer body Overlay 1st color adhesive / electrostatic, 2nd color or later adhesive / electrostatic, color overlay on intermediate transfer body 1st color adhesive, 2nd color or later melt adhesive, intermediate transfer body color overlay 1st color adhesive, 2nd color or later adhesive, transfer paper color Overlay 1st color electrostatic, 2nd color and later electrostatic, color overlay on transfer paper

As described above with reference to FIGS. 1 and 2, when the toner image on the intermediate transfer member 102 is secondarily transferred to the transfer paper 120, the front end of the full-color toner image on the intermediate transfer member 102. The transfer paper 120 is fed at a timely timing in accordance with the above, but a paper feed failure occurs due to deterioration of the paper feed roller 114, and the transfer paper 120 is delivered to the registration roller 115.
May not be transported. In order to deal with such a transfer paper conveyance trouble, that is, a jam, the above-described registration detection sensor 116 is set a fixed time after the paper feed motor clutch (paper feed MC) is turned on to start the rotation of the paper feed roller 114. When does not detect the leading edge of the transfer sheet, the CPU determines that a transfer sheet supply failure, that is, a jam has occurred. FIG. 2 (10) shows an operation state of the registration detection sensor 116 when the transfer sheet 120 is conveyed without causing a jam, and the jam detection timing of the transfer sheet is shown as "jam 1". . The operation when the "jam 1" is detected will be described later.

On the other hand, the transfer paper 120 is the registration roller 11
When the transfer sheet 120 is normally conveyed in the vicinity of the sheet 5 without causing a jam, the transfer sheet 120 is finally discharged to the sheet discharge section 119. However, as shown in FIG. A discharge detection sensor 118 is provided, and this sensor 118
Also, the jam of the transfer paper 120 is detected. That is, the above-mentioned registration detection sensor 1
When the discharge detection sensor 118 does not turn on after a lapse of a fixed time after 16 detects the leading edge of the transfer paper 120 and turns on, the CPU detects the transfer paper 120 between the registration roller unit and the discharge unit. Judge that a jam has occurred. (11) of FIG. 2 shows the discharge detection state when such a jam does not occur, and the above-mentioned determination timing when the jam occurs is shown as "jam 2". The operation when the "jam 2" is detected will also be described in detail later.

As can be seen from the above-mentioned details, the intermediate transfer member 102, the photosensitive drum 101, and the intermediate transfer member 1
02 and the pressure roller 103 are supported so as to be able to come into contact with and separate from each other. Therefore, for example, the intermediate transfer body 102 is separated from the photosensitive drum 101 and the pressure roller 103 is separated during the standby time other than the image forming operation. The intermediate transfer body 102 can be separated, the load applied to the surfaces of the photosensitive drum 101, the intermediate transfer body 102, and the pressure roller 103 can be reduced, and the life of the intermediate transfer body 102 can be extended. The load on the drive shaft can be reduced.

Further, as in this example, the photosensitive drum 101
The toner images of different colors are sequentially transferred onto the intermediate transfer member 102, and the toner images are sequentially transferred onto the transfer paper 120. When the toner images are transferred onto the transfer paper 120, the intermediate transfer member 102 is added at the time of the primary transfer. Since the pressure roller 103 can be separated and the photosensitive drum 101 and the intermediate transfer member 102 can be separated from each other at the time of the secondary transfer, the toner image on the intermediate transfer member 102 can be separated from the pressure roller 103 or the photosensitive member. It is possible to prevent the problem of shifting to the drum 101.

At this time, as is clear from the detailed description above, the photosensitive drum 101 and the pressure roller 103 are
Are rotatably supported but fixed in position,
The intermediate transfer body 102 is rotatable and is movably supported so as to come into contact with and separate from the photosensitive drum 101 and the pressure roller 103, and at least during the primary transfer, the intermediate transfer body 1
02 is pressed against the photosensitive drum 101, and the intermediate transfer member 102 is pressed against the pressure roller 103 via the transfer paper 120 at least during the secondary transfer. Therefore, the intermediate transfer member 102 and the photosensitive drum 101 are connected. , And intermediate transfer member 1
02 and the pressure roller 103 can be brought into contact with and separated from each other by an extremely simple mechanism. Each element 10
Only the intermediate transfer member 102 among these elements is moved in order to contact and separate 1, 102 and 103.

Conventionally, it is generally considered that at least two elements out of the three elements of the photosensitive drum, the intermediate transfer member and the pressure roller are movably supported and the respective elements are brought into contact with and separated from each other. Therefore, the contacting / separating mechanism must be very complicated, and the cost of the image forming apparatus rises. However, according to the above-described configuration of the present invention, such a problem can be easily solved. It can be resolved.

Further, as described above, when the intermediate transfer member 102 moves so as to come into contact with and separate from the photosensitive drum 101 and the pressure roller 103, the toner image on the intermediate transfer member 102 is secondarily transferred onto the transfer paper 120. The cleaning device 112 that cleans the surface of the intermediate transfer body 102 after
02, and in this example, the heater 121 and the temperature sensor 123 shown in FIG. 1 also move together, so that the overall configuration can be further simplified.

For example, as shown in FIGS. 3 and 4, the rotary shaft 202 of the intermediate transfer member 102 and the cleaning device 11
2, both ends of the temperature sensor 123 and the heater 121 in the longitudinal direction are respectively supported by a common pair of support plates 1, and the left and right ends in the figure of each support plate 1 are connected to vertically extending guide rails 2 and 3. A rack 4 is slidably fitted, and a rack 4 is integrally provided at one end of the support plate 1. The rack 4 is meshed with a pinion 5 rotatably supported by the main body of the image forming apparatus. In order to bring the intermediate transfer member 102 into contact with and separate from the photosensitive drum 101 and the pressure roller 103, the intermediate transfer member 1
When 02 is moved up and down, an elevator motor ((25) in FIG. 2) not shown in FIGS. 3 and 4 is operated to rotationally drive the pinion 5, thereby operating both support plates 1 up and down. Let In this way, the intermediate transfer body 102 can be moved up and down together with the cleaning device 112, the temperature sensor 123, and the heater 121. As shown in FIGS. 3 and 4, the intermediate transfer body 102 is moved to the photosensitive drum 10.
1 or the pressure roller 103, or the intermediate transfer member 102 can be moved to the retracted position shown by the solid line in FIG.

As described above, the intermediate transfer member 102 and the photosensitive drum 101, or the intermediate transfer member 102 and the pressure roller 103 can be brought into contact with and separated from each other by a very simple contact and separation mechanism.

By the way, in the image forming apparatus shown in FIG. 1, the toner image on the intermediate transfer member 102 is transferred onto the transfer paper 120.
The heater 121 is configured to apply thermal energy to the toner image on the intermediate transfer member 102 for the purpose of secondary transfer to the toner. However, when such a melt secondary transfer method is not adopted, as described above. First, it is necessary to fix the toner image secondarily transferred to the transfer paper 120 on the transfer paper by the heat of the fixing device. As described above, no matter which method is adopted, a heat source exists in the main body of the image forming apparatus. Therefore, if the heat source is left as it is, the photoconductor drum 10 is excessively heated and its charging characteristic is deteriorated. The toner may be fused on the photosensitive drum 101.

In order to prevent such a problem, in this embodiment, as shown in FIG. 1 and as described above, the photosensitive drum 101 includes the intermediate transfer member 102 and the pressure roller 10.
The toner image on the photoconductor drum 101 is primarily transferred to the intermediate transfer member 102 located below the photoconductor drum 101 and above the photoconductor drum 101.

With this configuration, the heater 121 serving as a heat source
The fixing device and the intermediate transfer body 102 heated by the heater 121 are all located above the photoconductor drum 101, and the heat radiated from these is released upward, so that the photoconductor drum 101 is heated. It is possible to prevent defects affected by. As described above, with the extremely simple configuration of setting the position of the photoconductor drum 101, the photoconductor drum 101 can be protected from heat, and its characteristics can be prevented from being deteriorated and toner fusion can be prevented.

Further, the toner image on the intermediate transfer member 102 is
For example, it is melted by a heating means including a heater 121,
An image forming method in which the fused toner image is secondarily transferred onto a transfer paper 120, and as shown in FIG.
02 and the photoconductor drum 101 are supported so that they can be brought into contact with and separated from each other, and the intermediate transfer member 102 and the photoconductor drum 101 are pressed against each other at least during the primary transfer,
When the intermediate transfer body 102 and the photosensitive drum 101 are in pressure contact with each other as shown in (27) of FIG. 2, if the heater 121 is controlled so as not to operate, as shown in (29) of FIG. Therefore, the temperature rise of the photosensitive drum 101 can be suppressed more effectively.

That is, when the photosensitive drum 101 and the intermediate transfer member 102 are in pressure contact with each other, when the heater 121 is turned on to irradiate the intermediate transfer member 102, the intermediate transfer member 102 is heated, and this heat is intermediate. Since the power is directly transmitted to the photoconductor drum 101 that is in pressure contact with the transfer body 102, the photoconductor drum 101 is heated, and the above-described problem is likely to occur. On the other hand, as described above, the intermediate transfer member 102
If the heater 121 is turned off during the pressure contact between the photosensitive drum 101 and the photosensitive drum 101, the temperature of the intermediate transfer member 102 can be prevented from rising, so that the photosensitive drum 101 does not rise to an excessively high temperature and its characteristics are deteriorated. Alternatively, it is possible to effectively prevent the toner from being fused to the photosensitive drum 101.

In the embodiment shown in FIG. 2, (21),
As shown in (27) and (29), the photoconductor drum 10
After the primary transfer of the toner image on 1 to the intermediate transfer member 102,
After the intermediate transfer member 102 is separated from the photosensitive drum 101, the heater 121 is turned on to start applying thermal energy to the toner image on the intermediate transfer member 102, and the toner image on the intermediate transfer member 102 is transferred to the transfer paper 120. After the transfer to
The heater 121 is controlled so as to be turned off to prevent the photosensitive drum 101 from overheating.

Further, in the above-mentioned structure in which the toner image on the intermediate transfer member 102 is melted by the heating means such as the heater 121 and is secondarily transferred to the transfer paper 120, the surface temperature of the intermediate transfer member 102 is set to If the temperature detecting means detects that the surface temperature of the intermediate transfer member 102 has reached a predetermined value or higher, the image forming operation is interrupted. It is possible to more reliably prevent the characteristic deterioration and the problem that the toner is fused to the photosensitive drum 101, and protect the photosensitive drum 101.

The temperature sensor 123 described above constitutes an example of such a temperature detecting means. The temperature sensor 123 is composed of, for example, a thermocouple, a resistance temperature detector, an infrared sensor, etc., and as shown in FIG. 1, the intermediate transfer member 10 is arranged so as not to disturb the toner image on the intermediate transfer member 102.
It is opposed to 2 in a non-contact state. Alternatively,
The temperature sensor may be brought into contact with the surface of the intermediate transfer member outside the area where the toner image is formed on the intermediate transfer member 102, or may be brought into contact with the inside of the intermediate transfer member 102.

In general, the amount of heat radiated at both ends of the intermediate transfer member 102 is larger than that at the center of the intermediate transfer member 102, and the surface temperature of the intermediate transfer member 102 varies in the axial direction. The amount of heat energy supplied to both ends of the intermediate transfer member 102 is set to be larger than that in the central part thereof so that the temperature of the entire intermediate transfer member 102 can be accurately detected by the temperature sensor 123, and the entire surface temperature of the intermediate transfer member 102 is And the temperature sensor 123 corrects the difference between the temperature at the location where the temperature is detected and the intermediate transfer member 10
It is desirable to be able to detect the temperature of 2.

As shown in FIG. 6, the signal of the temperature sensor 123 for detecting the surface temperature of the intermediate transfer member 102 is inputted to the comparing means such as the comparator 6, and the output signal of the comparator 6 is inputted to the CPU 7. To do. The reference value of the comparator 6 is set to, for example, a value such that the characteristics of the photoconductor drum 101 are not deteriorated or the toner is not fused to the photoconductor drum 101. Sensor 12
The outputs of 3 are compared.

When the CPU 7 determines from the output of the comparator 6 that the surface temperature of the intermediate transfer member 102 has reached a predetermined temperature or higher, the image forming operation is interrupted by a command from the CPU 7. That is, the heater 121 is turned off, and when the photosensitive drum 101 and the intermediate transfer body 102 are in pressure contact, they are separated from each other, and when the intermediate transfer body 102 and the pressure roller 103 are in pressure contact, the pressure contact is also made. The intermediate transfer body 102 is released and brought to the retracted position. At this time, when the transfer paper 120 is present in the secondary transfer portion B, the transfer paper 120 is discharged to the paper discharge portion 119, and then the intermediate transfer body 102 and the pressure roller 103 are separated from each other. Of course, after that, the conveyor belt 122, the paper discharge roller 117, and the like are stopped, and the operations of the registration roller 115 and the paper feed roller 114 are interrupted.

However, the photosensitive drums 10 separated from each other
1. Regarding the rotation of the intermediate transfer body 102 and the pressure roller 103, it is preferable to continue this and cool them as early as possible.

Thus, the temperature of the intermediate transfer member 102 is constantly detected by the temperature sensor 123, and the intermediate transfer member 102 is detected.
When it is detected by the temperature sensor 123 that the surface temperature of the photosensitive drum 101 and thus the temperature of the photosensitive drum 101 has risen,
By interrupting the image forming operation, the photosensitive drum 1
It is possible to reliably prevent the deterioration of the characteristics and the fusion of the toner due to the overheating of No. 01.

When the temperature sensor 123 detects that the surface temperature of the intermediate transfer member 102 is lowered and the overheating of the photosensitive drum 101 can be avoided, the image forming operation is restarted by a command from the CPU 7. .

Here, a device that can cool the intermediate transfer member 102 is provided by providing a fan in the main body of the image forming apparatus, or providing a heat pipe in the intermediate transfer member 102, and by circulating a refrigerant therethrough. As described above, when it is detected that the surface temperature becomes equal to or higher than the predetermined value, the cooling device positively cools the intermediate transfer member 102, so that the photosensitive drum 101 is more reliably protected from heat. It is possible to protect and to restart the image forming operation at an early stage.

By the way, in the image forming apparatus shown in FIG. 1, when the transfer paper is dribbled, that is, jammed as described above, as shown by "jam 1" and "jam 2" in FIG. , Is configured to detect that jam. When such a jam of the transfer paper is detected, the fact is displayed on the display unit of the image forming apparatus main body, but conventionally, the entire operation of the image forming apparatus is stopped at the same time when the jam is detected, The image forming operation was stopped. When the operator removes the jammed paper, confirms the removal, and meets the conditions for image formation, the operator waits for a signal to start printing.

However, if the operation of the image forming apparatus is stopped at the same time when the jam occurs and the rotations of the photoconductor drum 101 and the intermediate transfer member 102 are stopped, a part of the photoconductor drum 101 is heated to a high temperature. Since the intermediate transfer body 102 is stopped while facing the heated intermediate transfer body 102, a large amount of heat is transferred to this portion from the intermediate transfer body 102, and the photosensitive drum 101 is heated in a locally abraded state. In this case, not only the charging characteristic of the photoconductor drum 101 is deteriorated, but also the surface of the photoconductor drum 101 may be destroyed.

Therefore, in this example, when a jam of the transfer paper 120 is detected, the photosensitive drum 101 and the intermediate transfer member 10 are
2 and the pressure roller 103 are in a pressed or separated state, the intermediate transfer member 102 is moved to the retracted position shown in FIG. 1, and the photosensitive drum 101 and the intermediate transfer member 1 are moved.
02, the intermediate transfer member 102 and the pressure roller 103 are separated from each other, and the rotations of the photosensitive drum 101 and the intermediate transfer member 102 are not stopped. After the jam is detected, the photosensitive drum 101 and the intermediate transfer member 102 are kept for a predetermined time. Is configured to continue to rotate. Then, after a lapse of a predetermined time, the photosensitive drum 101 and the intermediate transfer member 102 are stopped, and in this state, a jam is displayed on the display unit to inform the operator of the jam. In this way, the photosensitive drum 1
01 and the intermediate transfer member 102 are cooled while they are rotated for a predetermined time.

When the photosensitive drum 101 is rotated as described above, only a part thereof does not remain opposed to the high temperature intermediate transfer member 102, and it is possible to prevent overheating of the photosensitive drum 101. Moreover, by rotating the photosensitive drum 101 and the intermediate transfer member 102, they can be cooled effectively. The intermediate transfer body 102 and the photoconductor drum 101 can be more positively cooled by operating the cooling device described above. In addition, the intermediate transfer member 102
Since the sheet is rotating, it is possible to prevent heating of the transfer sheet 120 that has caused a jam, and it is possible to prevent problems caused by excessive heat being applied to the transfer sheet.

Further, the photosensitive drum 101 and the intermediate transfer member 10
During the above rotation of 2, they are separated from each other,
Even if a toner image is formed on the intermediate transfer member 102, the problem of reverse transfer of the toner image to the photosensitive drum 101 does not occur. When a jam is detected, the heater 121 or the like is turned off to stop the image forming operation, which is no different from the conventional method.

In the present example, as described above, the jam of the transfer paper 120 is detected at the timings of "jam 1" and "jam 2" shown in FIG. 2, so these jams are detected. The operation at that time will be described below.

First, the jam 1 is detected by checking whether or not the transfer paper 120 supplied to the secondary transfer portion B is jammed. When the jam 1 is detected, the jam detection flag is detected. Is set (see (12) in FIG. 2), the jam is recognized, and the operation related to image formation is stopped. That is, the paper feed MC is turned off and the paper feed roller 11
4 is stopped, the heater 121 is turned off, and the intermediate transfer member 102 is turned off.
The heating operation of the upper toner is interrupted, the pressure MC is turned off, and the rotation of the pressure roller 103 is stopped. Further, the cleaning device 112 for the intermediate transfer body 102 does not operate, the cleaning operation for the intermediate transfer body 102 is not performed, the resist MC does not turn on, and the registration roller 115 does not turn on.
Does not rotate. At the time of this jam detection, the photosensitive drum 101, the intermediate transfer member 102, and the pressure roller 103 are separated from each other.
This separated state is maintained, and the intermediate transfer body 102 and the pressure roller 103 do not come into pressure contact with each other.

At the time of normal operation, first, the intermediate transfer member 102
The pressure roller 103, which is not in contact with the transfer roller 120, is controlled so as to be pressed against the intermediate transfer member 102 in accordance with the conveyance of the transfer paper 120 ((27) in FIG. 2). When (jam 1) occurs, the intermediate transfer member 102
Therefore, pressure contact between the two is prohibited so that the toner is not directly transferred to the surface of the pressure roller 103.
Thus, when the transfer paper 120 does not exist between the intermediate transfer body 102 and the pressure roller 103, the pressure roller 103
Are controlled so as not to come into pressure contact with the intermediate transfer member 102.

Although the image forming operation is stopped as described above, the photoconductor drum 101 and the intermediate transfer member 102 continue to rotate for a predetermined time even if the jam 1 is detected, and a jam display is displayed along with the stop. And wait for operator's operation. When the operator removes the jammed transfer paper and the CPU judges that fact, the image forming apparatus is started up, and the image forming operation is continued by pressing the print key by the operator. In this way, the operation can be continued without overheating the photosensitive drum 101.

On the other hand, when the above-mentioned "jam 2" is detected, the operation relating to the secondary transfer, that is, the resist MC,
The heater, the pressure contact of the secondary transfer portion, and the pressure MC are all stopped or released, the jam detection flag is set, and the jam is recognized. However, also in this case, the photosensitive drums 1 separated from each other
01 and the intermediate transfer member 102 continue to rotate, and the photosensitive drum 1
Allow 01 to cool.

At this time, since the secondary transfer is stopped midway, the trailing edge portion of the toner image remains on the intermediate transfer member 102. Therefore, as described above, the rotation of the intermediate transfer body 102 is continued and the cleaning device 112 is operated to clean the intermediate transfer body 102. After stopping the rotation of the photosensitive drum 101 and the intermediate transfer member 102, the operator is notified of the fact that a jam has occurred, and the operator's operation is waited for.

The fact that the jammed transfer paper has been removed C
When the PU judges, the image forming apparatus is started up and the operator waits for the next operation. At this time, the state of the image forming apparatus main body is the initial state. However, the setting value of the first image formation state,
For example, input data such as the number of copies, the magnification, and the copy size remain in the memory. Therefore, if the operator continuously presses the print key, only the remaining number of copies before the jam occurs will be output.

By the way, in the image forming apparatus shown in FIGS. 1 and 2, it is detected whether the transfer paper 120 supplied to the secondary transfer portion B where the secondary transfer is performed has a conveyance trouble, that is, a jam. 1 is detected after the primary transfer is completed and the intermediate transfer body 102 and the photosensitive drum 101 are separated from each other.
It is configured to be performed before pressure contact with 3, that is, before secondary transfer is performed. In other words, when the jam 1 is detected, the entire output image, that is, a full-color toner image in this example is already formed on the intermediate transfer member 102, and all the toner images on the photosensitive drum 101 are intermediate transferred. The primary transfer to the body 102 has been completed.

By setting the detection timing of the jam 1 at such a timing, the cleaning device 1 for cleaning the photosensitive drum 101 even when the fine particle toner is used.
The burden on 11 can be effectively reduced. The operation at this time will be described with reference to FIG.

As shown in FIGS. 7A, 7B, and 7C, all toner images have been formed on the photosensitive drum 101, and the toner images are all primary formed on the intermediate transfer member 102. After the transfer is completed, it is checked whether or not the jam 1 has occurred. Here, when the jam 1 is not detected, the normal sequence described above is performed (FIG. 7D), and when the jam 1 is detected, the image forming operation is stopped as described above (see FIG. 7). (E)). However, in this example, the photosensitive drum 101 and the intermediate transfer member 102 are stopped for a predetermined time after being rotated.

Next, when the operator removes the jammed transfer paper and the CPU judges that the transfer paper has been removed ((f) in FIG. 7), the image forming apparatus is started up and the next operation of the operator is waited for. However, at this time, a full-color toner image is formed on the intermediate transfer member 102.

Here, for example, when the operator does not need the toner image formed on the intermediate transfer body 102, the operator uses the intermediate transfer for cleaning the toner image on the intermediate transfer body 102 on the operation unit. Input the body cleaning switch (not shown). As a result, the intermediate transfer body 102 starts rotating in the counterclockwise direction in FIG. 1, the heater 121 is turned on to melt the toner image on the intermediate transfer body 102, and the cleaning device 112 is activated to bring the intermediate transfer body 102 into operation. The upper toner image is removed and the surface is cleaned ((g) and (h) in FIG. 7). At this time, the photosensitive drum 101 and the pressure roller 103 are separated from the intermediate transfer body 102.

As described above, since the toner image on the photosensitive drum 101 is not cleaned, the cleaning device 11
The load of No. 1 can be reduced and its life can be extended.
Further, since the toner image on the intermediate transfer member 102 is made into a molten state and is removed by the cleaning device 112, the cleaning device 11 rather than removing the powdery toner.
The load on the cleaning device 112 can be reduced and the life of the cleaning device 112 can be prevented from being shortened.

Conventionally, when a jam occurs, a toner image is formed on the photosensitive drum. Therefore, after removing the jammed paper, the toner image on the photosensitive drum is cleaned and removed by the cleaning device. Since the cleaning device for the photoconductor drum is configured to perform the forming operation, the cleaning device for the photoconductor drum may have a large load, and the life thereof may be shortened. At the time of detection, all the toner images on the photoconductor drum 101 have already been primary-transferred to the intermediate transfer body 102, so that there is no problem as in the conventional case.

On the other hand, instead of removing the toner image on the intermediate transfer member 102 by the cleaning device 112 as described above, unnecessary paper (miscopy paper or the like) generated in an office or the like is supplied to the secondary transfer portion B. The intermediate transfer member 10 is sent and melted by the heater 121 while pressing the paper against the intermediate transfer member 102 by the pressure roller 103.
It is also possible to fix the toner image on No. 2 onto the paper simultaneously with the secondary transfer ((i) and (j) in FIG. 7). At this time, the toner image on the intermediate transfer body 102 may be electrostatically secondarily transferred to the paper. The intermediate transfer body 102 after the toner image is transferred to the paper is cleaned by the cleaning device 112.

In this way, the toner image on the intermediate transfer member 102 is secondarily transferred to unnecessary paper and discharged to the paper output unit 119, so that the load on the cleaning device 112 for the intermediate transfer member 102 can be further reduced. , Its longevity can be achieved. Moreover, since the toner image is transferred to the paper that is originally discarded, the waste can be effectively used. A separate paper feed unit for storing unnecessary paper (mis-copy paper) generated in the office is provided, and unnecessary paper is fed from this paper feed unit and the toner image is secondarily transferred to it during the above operation. It can also be configured as follows.

Further, a new unused transfer sheet 120 is fed from the sheet feeding section 113 shown in FIG. 1 to the secondary transfer section B in exactly the same manner as described above, and the intermediate transfer body 102 is fed thereto.
The toner image on the top is transferred, and the transfer paper 120 is ejected to the paper ejection unit 11
If it is discharged to 9, the transfer paper can be used as it is as a completed copy paper, and wasteful consumption of toner can be prevented ((k) and (l) in FIG. 7).

In this way, after the transfer paper having the supply failure is removed, the toner image formed on the intermediate transfer member 102 is secondarily transferred to the newly supplied transfer paper (unnecessary paper or new paper). By doing so, the cleaning device 1
The burden on 12 can be effectively reduced.

After the removal of the jammed paper, the intermediate transfer body 102 is cleaned as described above, and when the conditions for forming an image are satisfied, the signal for the print start is waited for. In addition to the cleaning of the intermediate transfer member 102, the photosensitive drum 101 may be cleaned by the cleaning device 111 as necessary, but at this time, the toner image before the primary transfer is also formed on the photosensitive drum 101. Is not formed, it is possible to prevent the burden on the cleaning device 111 from becoming excessive.

When the operator wants to transfer the toner image formed on the intermediate transfer member 102 to new transfer paper (unnecessary paper or new paper) and output it, By inputting an image output switch (not shown), a new transfer paper may be fed from the paper feeding unit, and the toner image may be secondarily transferred and simultaneously fixed on the transfer paper to be output. At this time, the intermediate transfer member 10
Since it is necessary to feed a new transfer sheet at the timing when the transfer sheet matches the toner image on 2, the detector (not shown) for detecting the home position of the intermediate transfer member 102 is provided, and thereby the home It is desirable to detect the position and feed the transfer paper at the timing when the front end of the toner image on the intermediate transfer body 102 and the front end of the new transfer paper match.

Although not shown in FIG. 7, before the image forming operation is stopped when the jam 1 occurs, or after the jammed paper is removed, etc., without operating the intermediate transfer member cleaning switch, Alternatively, the toner image on the intermediate transfer member 102 may be automatically melted, and the toner image may be cleaned by the cleaning device 112.

By the way, in the structure shown in FIG. 1, the toner of the toner image formed on the intermediate transfer member 102 is transferred to the heater 1.
The molten toner is secondarily transferred to a recording medium that is pressed against the intermediate transfer member 102 by the pressure roller 103. The recording medium is not only paper quality such as plain paper, but also resin. Often used. For example, it is widely practiced to use a resin sheet for an overhead projector as a recording medium and form a final image on the recording medium. Such a resin sheet generally has a large heat capacity. Therefore, in order to secondarily transfer the molten toner image on the intermediate transfer member 102 onto the resin sheet, the toner image is melted and secondarily transferred onto the transfer paper 120 made of plain paper. It is necessary to apply a large amount of heat energy to the toner image formed on the intermediate transfer body 102, as compared with the case.

On the other hand, in the timing chart shown in FIG. 2, when the toner image on the intermediate transfer member 102 is secondarily transferred, the toner image is transferred from the heater 123 to the toner image during one rotation of the intermediate transfer member 102. Although thermal energy is applied, when a resin-made recording medium is used, the intermediate transfer member 10 is not subjected to such thermal energy application.
It may be difficult to reliably transfer the toner image on No. 2 onto the recording medium and fix the toner image at the same time.

Therefore, when the recording medium is made of resin, the intermediate transfer member 10 is maintained while the heater 123 is still operating.
2 is rotated a plurality of times to apply sufficient heat energy to the toner image on the intermediate transfer body 102 to melt it, and then the recording medium is fed to transfer the toner image on the intermediate transfer body 102 to the recording medium. It is advantageous to configure the next transfer. In this way, a high quality final image can be obtained regardless of the material of the recording medium.

As the recording medium, not only the material but also those having various thicknesses are used. In the conventional image forming apparatus of this type, the pressure between the intermediate transfer member and the pressure roller is always constant. Since it was kept constant, when the recording medium was particularly thick, it was difficult to pass it between the intermediate transfer member and the pressure roller, and the image of the image secondarily transferred to this recording medium deteriorates. There was a fear. If the pressure between the intermediate transfer member and the pressure roller is changed depending on the material of the recording medium and the pressure is not adjusted to an appropriate value, the image quality of the image may deteriorate.

Therefore, in this example, the pressure at which the intermediate transfer member 102 and the pressure roller 103 are brought into pressure contact with each other is changed according to the thickness of the recording medium and its material, and an appropriate pressure is obtained for each recording medium. Is configured. For example, when a thick recording medium is used, the pressure contact force between the intermediate transfer member 102 and the pressure roller 103 is weakened so that the thick recording medium can surely pass between them. Specifically, when the intermediate transfer body 102 is pressed against the pressure roller 103, the rotation amount of the pinion 5 shown in FIGS. 3 and 4 is controlled so that the intermediate transfer body 102 and the pressure roller 103 are pressed against each other. The power can be adjusted. In this way, a high quality image can be formed on a recording medium of any material and of any thickness. Further, the gap between the pair of registration rollers 115 or the gap for the pair of discharge rollers can be adjusted according to the thickness of the recording medium.

The embodiments in which the present invention is applied to the image forming method capable of forming a color image have been described above.
It can also be applied exclusively to an image forming method for obtaining a single-color image. In this case, a toner image of one color is formed on an image carrier, this image is primarily transferred to an intermediate transfer member, and then this is secondarily transferred to a recording medium. do it.

[0147]

According to the image forming method of the first aspect, since only the intermediate transfer member is moved to bring the image carrier and the intermediate transfer member, and the intermediate transfer member and the pressure rotator into contact and separation, The configuration can be simplified.

According to the image forming method of claim 2,
Since the cleaning device for the intermediate transfer body can also move together with the intermediate transfer body, the structure can be further simplified.

According to the image forming method of the third to seventh aspects, it is possible to protect the image bearing member from heat, prevent deterioration of its characteristics, and achieve a long life of the image bearing member.

According to the image forming method of claim 8,
It is possible to reduce the load on the cleaning device that cleans the surface of the image carrier after the transfer of the toner image.

According to the image forming method of claim 9,
Even when the recording medium is made of resin, a high quality image can be formed on it.

According to the image forming method of the tenth aspect, it is possible to form a high-quality image on the recording medium regardless of the thickness and paper quality.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of an image forming apparatus for carrying out a method according to the present invention.

FIG. 2 is a timing chart showing an example of the image forming sequence.

FIG. 3 is an explanatory diagram showing a state in which an intermediate transfer member is in pressure contact with a photosensitive drum.

FIG. 4 is an explanatory diagram showing a state in which an intermediate transfer member is in pressure contact with a pressure roller.

FIG. 5 is an enlarged cross-sectional view of an intermediate transfer member.

FIG. 6 is a block diagram of an embodiment of the present invention.

FIG. 7 is a flowchart of an embodiment of the present invention.

[Explanation of symbols]

 102 intermediate transfer member 112 cleaning device

Claims (10)

[Claims] 1. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is pressed against the image carrier while being rotationally driven, and the toner image is rotated under pressure. In an image forming method of secondarily transferring to a recording medium pressed against an intermediate transfer body by a body, the image carrier and the pressure rotator are both rotatably but immovably supported, and the intermediate transfer body is supported. , Is rotatable and is movably supported so as to come into contact with and separate from the image bearing member and the pressure rotator, and at least during the primary transfer, the intermediate transfer member is brought into pressure contact with the image bearing member, and at least the secondary member An image forming method, wherein an intermediate transfer member is brought into pressure contact with a pressure rotating member via the recording medium during transfer. 2. The image forming apparatus according to claim 1, wherein a cleaning device for cleaning the surface of the intermediate transfer body after the toner image on the intermediate transfer body is secondarily transferred to the recording medium is moved together with the intermediate transfer body. Method. 3. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is pressed against the image carrier while being rotationally driven, and the toner image is rotated under pressure. In an image forming method of secondarily transferring to a recording medium pressed against an intermediate transfer body by a body, the image carrier is arranged below the intermediate transfer body and the pressure rotator, and is located above the image carrier. An image forming method characterized in that a toner image on an image carrier is primarily transferred onto an intermediate transfer body. 4. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is in pressure contact with the image carrier while being rotationally driven, and the toner of the toner image is heated by a heating unit. In the image forming method in which the fused toner image is secondarily transferred to the recording medium pressed against the intermediate transfer body by the pressure rotating body, the intermediate transfer body and the image carrier are supported so that they can be separated from each other. Then
At least the intermediate transfer member and the image bearing member are brought into pressure contact with each other during the primary transfer, and the heating unit is controlled so as not to operate when the intermediate transfer member and the image bearing member are in pressure contact. Image forming method. 5. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is in pressure contact with the image carrier while being rotationally driven, and the toner of the toner image is heated. In the image forming method in which the fused toner image is secondarily transferred to the recording medium pressed against the intermediate transfer body by the pressure rotating body, the surface temperature of the intermediate transfer body is detected by the temperature detecting means, An image forming method characterized in that the image forming operation is interrupted when the temperature detecting means detects that the surface temperature of the intermediate transfer member has reached a predetermined value or higher. 6. A toner image is formed on a rotationally driven image bearing member, the toner image is primarily transferred to an intermediate transfer member which is in pressure contact with the image bearing member while being rotationally driven, and the toner image is rotated under pressure. In the image forming method of secondarily transferring to the recording medium pressed against the intermediate transfer body by the body, when the conveyance trouble of the recording medium is detected, the rotation of the image carrier is not stopped and the rotation is continued. Image forming method. 7. A toner image is formed on a rotationally driven image bearing member, the toner image is primarily transferred to an intermediate transfer member that is in pressure contact with the image bearing member while being rotationally driven, and the toner image is rotated under pressure. In the image forming method of secondarily transferring to the recording medium pressed against the intermediate transfer body by the body, when the conveyance trouble of the recording medium is detected, the rotation of the intermediate transfer body is not stopped and the rotation is continued. Image forming method. 8. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is in pressure contact with the image carrier while being rotationally driven, and the toner image is rotated under pressure. In the image forming method of secondarily transferring to the recording medium pressed against the intermediate transfer body by the body, the intermediate transfer body and the image carrier are supported so that they can be contacted and separated from each other, and the intermediate transfer body and the pressure rotating body are contacted with each other. Releasably supported, at least during the primary transfer, the intermediate transfer body and the image carrier are brought into pressure contact with each other, and at least during the secondary transfer, the intermediate transfer body and the pressure rotator are brought into pressure contact with each other via the recording medium. At the same time, it is detected whether or not the recording medium supplied to the secondary transfer portion in which the secondary transfer is performed has a transport trouble after the intermediate transfer body and the image carrier are separated from each other. And the pressure rotor Image forming method characterized by performing between before. 9. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is in pressure contact with the image carrier while being rotationally driven, and the toner of the toner image is heated. In the image forming method of secondarily transferring the melted toner image to the recording medium pressed against the intermediate transfer body by the pressure rotating body, when the recording medium is made of resin, the heating means is An image forming method comprising rotating an intermediate transfer member a plurality of times while operating, and then secondarily transferring a toner image on the intermediate transfer member to a recording medium. 10. A toner image is formed on an image carrier that is rotationally driven, and the toner image is primarily transferred to an intermediate transfer member that is in pressure contact with the image carrier while being rotationally driven, and the toner image is rotated under pressure. In an image forming method of secondarily transferring to a recording medium pressed against an intermediate transfer body by a body, changing the pressure at which the intermediate transfer body and the pressure rotating body are brought into pressure contact with each other according to the thickness of the recording medium and its material. And an image forming method.