JPH06250531A - Heat insulating device between fixing device and transfer device - Google Patents

Abstract

PURPOSE:To prevent the deformation of a transfer material carrier with a simple structure and downsize a device. CONSTITUTION:In an image forming device having an image carrier an image forming means for forming an electrostatic latent image on the image carrier, a developing means for developing the electrostatic latent image to a toner image, a transfer device 14 for electrostatically attracting a transfer material P on a transfer carrier 34 formed out of a dielectric film and transferring the toner image formed on the image carrier onto the transfer material, a releasing device 31 for releasing the transfer material P from the transfer material carrier 34, and a fixing device 30 for heating and fixing the transferred toner image, the peeling device 31 is arranged in such a manner as to be rotatable to the position close to the transfer material carrier 34 to release the transfer material P and the position for thermally insulating the inlet side opening part 48 of the fixing device 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer and a facsimile, and more particularly to an image forming apparatus provided with a transfer device using a transfer material carrier made of a dielectric film and a heating type fixing device. The present invention relates to a heat shield device between a fixing device and a transfer device.

[0002]

2. Description of the Related Art Conventionally, for example, in a color electrophotographic copying machine, yellow, cyan, magenta, and black latent images are sequentially formed on an image carrier, and the latent images of yellow, cyan, magenta, and black are formed. The toner image developed by the developing device is transferred to a transfer material on a rotating transfer drum in contact with the image carrier, and the transfer drum is rotated four times to
A method is known in which four-color full-color copies are obtained by superimposing and transferring color toner images on a transfer material.

In the transfer device of the above image forming apparatus,
In order to superimpose images on one transfer material with high accuracy,
A transfer carrier made of a dielectric film is fixed to the outer periphery of the transfer drum, and the transfer material is electrostatically adsorbed to the transfer material carrier.
Transfer is performed so that the transfer material is brought into close contact with the peripheral surface of the image carrier, and the charge of the transfer material after completion of the transfer is removed by a charge-eliminating corotron and separated by a separating claw.

By the way, in an image forming apparatus in which a transfer device using the transfer material carrier is combined with a heating type fixing device, the transfer material carrier contracts or relaxes due to heat conduction and radiant heat from the fixing device. There is a problem that the material cannot be conveyed to the transfer portion in a smooth state and the image quality is deteriorated.

Conventionally, in order to solve this problem, as shown in Japanese Patent Laid-Open No. 1-303463 and Japanese Utility Model Laid-Open No. 63-20172, a means for keeping the transfer material carrier constant at a temperature higher than the ambient temperature. To prevent local deformation of the transfer material carrier, the transfer carrier is constantly rotated, and the distance between the fixing device and the transfer device is not affected by heat from the fixing device. Although it is moved farther to the position, it has a drawback that it causes an increase in size of the device and that a heating means must be provided.

To solve this, Japanese Patent Laid-Open No. 61-147
Japanese Laid-Open Patent Publication No. 276 proposes a system in which an opening / closing means for opening / closing the entrance side of the fixing device is provided, and the entrance side of the fixing device is closed by the opening / closing means except when fixing the transfer material.

[0007]

However, in the system disclosed in Japanese Patent Laid-Open No. 61-147276, an opening / closing plate for opening / closing the entrance side of the fixing device and a solenoid for operating the opening / closing plate must be provided. Not
There is a problem that the structure becomes complicated and the cost also increases.

The present invention is to solve the above problems, and in an image forming apparatus provided with a transfer device using a transfer material carrier made of a dielectric film and a heating type fixing device, special members and devices are provided. To provide a heat shield device which can prevent the transfer material carrier from being deformed by a simple structure without using the structure and can reduce the distance between the fixing device and the transfer device to thereby downsize the device. With the goal.

[0009]

In order to achieve the above object, a heat shield device between a fixing device and a transfer device according to the present invention comprises an image carrier and an image forming an electrostatic latent image on the image carrier. Forming means, developing means for developing the electrostatic latent image into a toner image, and electrostatically adsorbing the transfer material on a transfer material carrier made of a dielectric film to form a toner image on the image carrier. An image forming apparatus comprising: a transfer device for transferring onto a transfer material; a peeling device for peeling the transfer material from a transfer material carrier; and a fixing device for heating and fixing the transferred toner image, wherein the peeling device Is rotatably disposed at a position where the transfer material is peeled off in the vicinity of the transfer material carrier and at a position where the inlet side opening of the fixing device is thermally blocked. In addition to the above configuration, a suction duct for sucking air may be provided between the peeling device and the inlet side opening of the fixing device.

[0010]

In the present invention, at the time of transfer by the transfer device, the peeling device is separated from the transfer material carrier and waits at a position where the entrance side opening of the fixing device is thermally shielded. The radiant heat from the transfer material carrier toward the transfer material carrier is blocked by the peeling device, and the heat is discharged through the suction duct as needed.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1, 2 and 3 show an embodiment in which the heat shield device according to the present invention is applied to a color electrophotographic copying machine, and FIG. 1 (A) is an enlarged sectional view between the fixing device and the transfer device in FIG. 1 (B) and 1 (C) are enlarged side views for explaining the operation of the peeling device, FIG. 2 is an overall configuration diagram, and FIG.
3 shows one embodiment of the peeling apparatus according to the present invention, and FIG.
FIG. 3A is a plan view and FIG. 3B is a front view including a transfer drum. The present invention is not limited to such a color electrophotographic copying machine, and can be applied to all image forming apparatuses of a system including a transfer device using a transfer material carrier made of a dielectric film and a heating type fixing device. It is a thing.

In FIG. 2, the color electrophotographic copying machine is
The automatic document feeder 1 includes an image input unit 2, an image output unit 3, and a transfer material feeding unit 4. The color original document is placed on the platen glass 5 by the automatic original document feeder 1. The image input unit 2 is composed of an imaging unit 6, a wire 7 for driving the unit, a drive pulley 9 and the like. Using a CCD line sensor and a color filter in the imaging unit 6, in the case of four full colors, After reading a color original for each of the primary colors of light B (blue), G (green), and R (red) and converting it into a digital image signal, this signal is the primary colors of toner Y (yellow) and C (cyan). ), M
(Magenta), K (black), and the color,
In order to improve the reproducibility of gradation, definition, etc., various data processing is performed to turn on / off the color gradation toner signal.
It is converted into a binarized signal and output to the image output unit 3.

The image output unit 3 has a scanner 10 and a drum-shaped image carrier 11 made of an organic photoconductor, and a charge for uniformly charging the image carrier 11 around the image carrier 11. A device 12, a developing device unit 13 for developing the electrostatic latent image into a toner image, a transfer device 14 for transferring the toner image onto a transfer material, and a cleaner 15 for collecting the untransferred residual toner are arranged. The image carrier 11 is rotationally driven by an electric motor as shown by an arrow.

In the laser output section 10a of the scanner 10, for example, a yellow image signal from the image input section 2 is converted into an optical signal, and an image carrier is passed through a polygon mirror 10b, an f / θ lens 10c and a reflection mirror 10d. A latent image corresponding to the original image is formed on 11. If this yellow latent image is transferred to a transfer material through development, the image carrier 1
After the residual toner is removed by the cleaner 15, 1 is charged again by the charger 12, and the laser output unit 10a is
Outputs a cyan image signal. Hereinafter, latent images of magenta and black image signals are sequentially formed.

The developing device unit 13 includes a yellow developing device 13Y, a cyan developing device 13C, and a magenta developing device 13.
M and black developing devices 13K are provided, and each developing device is arranged around the rotating shaft. Then, for example, when a yellow toner image is formed, development is performed by the yellow developing device 13Y at the position shown in the figure, and when a cyan toner image is formed, the developing device unit 13 is rotated to rotate the image carrier 1
The cyan developing device 13C is disposed at a position in contact with 1.
The magenta and black developments are similarly operated.

A transfer material carrier (described later) made of a dielectric film is stretched around the outer periphery of the transfer drum 16 as a transfer material conveying device. The transfer drum 16 is a dedicated electric motor or image carrier 11. Is connected by a gear and is rotationally driven as shown by an arrow. A transfer corotron 17, a pressing member 18, and a transfer member 16 are provided around the inside and outside of the transfer drum 16.
Separating corotron 19, stripping device 31, static eliminating corotron 2
1, cleaner 22, suction roll 23, suction corotron 2
5 are arranged.

The paper feed tray 4a of the transfer material supply unit 4
The transfer material that is conveyed and fed from the conveyance roller 26, the paper feed guide 27, and the registration roller 28 from 4d is conveyed between the suction roll 23 and the suction corotron 25 and is attracted to the transfer material carrier. The transfer drum 16 rotates in synchronization with the image carrier 11, and, for example, a toner image developed by yellow is transferred onto a transfer material by a transfer corotron 17, and after the transfer device makes one rotation, a toner image developed by cyan. Is transferred to the transfer material by the transfer corotron 17, and then other colors are sequentially superimposed and transferred. Transfer drum 1
When 6 has rotated four times and the transfer of four colors has been completed, the transfer material is discharged by the separating corotron 19, separated by the peeling device 31, and sent to the fixing device 30. The fixing device 30 includes a heating roll 30a and a pressure roll 30b, and the toner image on the transfer material is fused and fixed. Thereafter, this series of copy cycles is repeated.

FIG. 3 shows an embodiment of the peeling apparatus according to the present invention, FIG. 3 (A) is a plan view, and FIG. 3 (B) is a front view including a transfer drum. The present invention is not limited to such a peeling device, and may be any peeling device having a structure capable of blocking the heat from the fixing device among the conventional peeling devices.

The transfer drum 16 is rotatably supported by a frame 35, and a peeling device 31 is provided in the vicinity of the transfer drum 16. The transfer drum 16 includes a cylindrical member 32 provided on both sides, a connecting member 33 connected and fixed between the cylindrical members 32, and a transfer material carrier 34 made of a dielectric film. The side edge portion is fixed along the outer peripheral surface of the tubular member 32 with a double-sided adhesive tape or the like, the front edge portion and the rear edge portion of the transfer material carrier 34 are fixed to the connecting member 33, and a hollow cylindrical shape is formed inside. It forms a space.

Further, the peeling device 31 has a rotating shaft 36 rotatably supported by the frame 35, a support 37 rotatably attached to the rotating shaft 36, and a little from the center of the support 37. The peeling claw 2 which is fixed to the rotary shaft 36 at a separated position
0, a peeling guide member 38 located on both sides of the peeling claw 20 and fixed to the support body 37, a guide roller 39 attached to one end of the rotating shaft 36, and a support roller 37 on the side opposite to the guide roller 39. The guide roller 40 is attached.

An operating arm 41 is attached to one end of the rotating shaft 36, and between the operating arm 41 and the frame 35,
A spring 42 is stretched and thereby biases the peeling claw 20, the support body 37, and the peeling guide member 38 so as to rotate toward the front side in FIG. Also, the operating arm 4
A solenoid 43 is provided between the frame 1 and the frame 35,
This allows the peeling claw 20 and the peeling guide member 38 to
In, the front side can be rotated. With the above configuration, when the solenoid 43 is off, the peeling claw 20 and the peeling guide member 38 both stand by at the position separated from the transfer drum 16 by the spring 42, that is, at the position where the radiant heat from the fixing device 30 is blocked. When 43 is turned on, the peeling claw 20 is allowed to enter below the transfer material on the transfer material carrier 34 as the rotary shaft 36 rotates, and the peeling guide member 38 is allowed to stand by above the peeling claw 20. To be done.

On the other hand, the connecting groove 33 of the transfer drum 16 faces the peeling claw 20 and the clearance groove 44 into which the peeling claw 20 is inserted.
And the guide roller 39 is formed on one of the tubular members 32.
A guide groove 45 into which is inserted is formed. As shown in FIG. A, the peeling guide member 38 has an inclined surface 46 integrally formed on the front surface and a rib 47 on the rear side, and the inclined surface 46 is formed so as to retreat rearward as the distance from the peeling claw 20 increases. In addition, as shown in FIG. B, the height is lowered as the distance from the peeling claw 20 increases.

FIG. 1A is an enlarged sectional view between the fixing device 30 and the transfer device 14 in FIG. The peeling device 31 is
The fixing device 30 is disposed so as to face the entrance-side opening 48. The transfer material guide member 49 is provided below the entrance side opening 50.
A suction duct 29b is also provided, and a suction duct 29a is provided above the inlet side opening 48. The suction ducts 29a and 29b are connected to a fan (not shown), and the peeling device 31 and the inlet side opening 48 are connected. Sucks in the air between
Heat from the floating toner and the fixing device 30 is sucked into the duct 2.
It can be discharged through 9a and 29b.

The operation of the present invention having the above structure will be described. During transfer in which the transfer drum 16 is repeatedly rotated and stopped, the solenoid 43 is turned off and the spring 42
1A, the peeling claw 20, the support body 37, and the peeling guide member 38 are separated from the transfer drum 16, and the support body 37 and the peeling guide member are moved, as shown in FIG. 38 is an inlet side opening portion 48 of the fixing device 30.
It stands by at the position where it is thermally cut off. In this state, the radiant heat from the inlet opening 48 toward the transfer material carrier 34 is blocked by the support 37 and the peeling guide member 38, and the heat is discharged through the suction ducts 29a and 29b. Therefore, the transfer material carrier 34 can be prevented from being deformed and the distance between the fixing device 30 and the transfer device 14 can be shortened with a simple configuration without providing any special member and device, so that the device can be downsized. Can be planned.

When the transfer material P is peeled off after the transfer is completed, the solenoid 43 is driven to rotate the rotary shaft 36 in the direction in which the peeling claw 20, the support body 37, and the peeling guide member 38 approach the transfer drum 16. The one guide roller 40 comes into contact with the tubular member 32 and stands by at the position shown in FIG. When the transfer drum 16 further rotates, the other guide roller 39 enters the guide groove 45 formed in the tubular member 32. As a result, as shown in FIG. 1C, only the peeling claw 20 rotates with the peeling guide member 38 stopped, and the tip of the peeling claw 20 scoops the tip of the transfer material P to transfer the transfer material P.
Are separated from the transfer material carrier 34.

As soon as the transfer material P is separated by the peeling claw 20, the peeling claw 20 returns to the standby position in FIG. 1 (B).
At this time, since the peeling guide member 38 does not rotate, the tip portion can be brought as close to the transfer drum 16 as possible, and good peeling performance can be obtained. After the transfer material has passed, the peeling claw 20 is returned to the position of FIG. 1A by turning off the solenoid 43, and in synchronization with this, the support body 37 and the peeling guide member 38 are also separated from the transfer drum 16 and again supported. Body 37
The peeling guide member 38 blocks radiant heat from the inlet side opening 48 of the fixing device 30 toward the transfer material carrier 34, and prepares for the next transfer cycle.

When the transfer material is peeled off, the fixing device 30 is used.
Radiant heat is temporarily transferred from the inlet side opening 48 to the transfer material carrier 34, but since the transfer drum 16 is rotating, the transfer material carrier 34 is not locally deformed.

FIG. 4 shows another embodiment of the present invention, in which a transfer belt is used as a transfer material carrier. In addition,
The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. Transfer belt 50 that constitutes the transfer device 14
Is equipped with an endless belt-shaped dielectric film, is wound around a driving roll 51 and a driven roll 52, and is rotated in the direction of the arrow. Four sets of image forming units K, Y, M, and C for black, yellow, magenta, and cyan are arranged facing the transfer belt 50, and one rotation of the transfer belt 50 makes four color toner images. Are transcribed one after another.

[0029]

As is apparent from the above description, according to the present invention, in the image forming apparatus including the transfer device using the transfer material carrier made of the dielectric film and the heating type fixing device, the special member and device are provided. With a simple configuration without the provision of the above, the transfer material carrier can be prevented from being deformed, and the distance between the fixing device and the transfer device can be shortened, so that the size of the device can be reduced.

[Brief description of drawings]

FIG. 1 shows an embodiment of a heat insulation device according to the present invention,
1A is an enlarged cross-sectional view between the fixing device and the transfer device in FIG. 2, and FIG. 1B and FIG. 1C are enlarged side views for explaining the operation of the peeling device.

FIG. 2 is an overall configuration diagram showing an embodiment in which the heat shield device according to the present invention is applied to a color electrophotographic copying machine.

3A and 3B show an embodiment of a peeling device according to the present invention, FIG. 3A is a plan view, and FIG. 3B is a front view including a transfer drum.

FIG. 4 shows another embodiment of the present invention, in which a transfer belt is used as a transfer material carrier.

[Explanation of symbols]

11 ... Image carrier, 10, 12 ... Image forming means, 13 ... Developing means, 14 ... Transfer device 16 ... Transfer drum, 20 ... Separation claws, 29a, 29b ... Suction duct 30 ... Fixing device, 31 ... Separation device, 34 ... Transfer material carrier 38 ... Separation guide member, 48 ... Entrance side opening, 50 ... Transfer drum, P ... Transfer material

Claims (2)

[Claims] 1. An image carrier, image forming means for forming an electrostatic latent image on the image carrier, developing means for developing the electrostatic latent image into a toner image, and a transfer material carrier comprising a dielectric film. A transfer device for electrostatically adsorbing the transfer material on the body to transfer the toner image formed on the image carrier onto the transfer material; and a peeling device for peeling the transfer material from the transfer material carrier. In the image forming apparatus including a fixing device that heat-fixes the transferred toner image, the peeling device heats the position where the transfer material is peeled off in proximity to the transfer material carrier and the opening on the inlet side of the fixing device. A heat shield device between a fixing device and a transfer device, wherein the heat shield device is rotatably disposed at a position where the heat is blocked. 2. A suction duct for sucking air is provided between the peeling device and an opening on the inlet side of the fixing device, between the fixing device and the transfer device. Thermal shutoff device.