JPH06239490A - Conveyor device for transfer material - Google Patents

Abstract

PURPOSE:To prevent the generation of wrinkles and image slippage in transfer material with moisture absorbed therein regardless of the quality, size, and the like of the transfer material by providing a control means for, switching the action timing of suction means according to the sort of the transfer material so as to suck at least the tip part and rear end part of the transfer material. CONSTITUTION:A control part is provided with a CPU 30. An ROM 32 is stored with a suction control program in addition to a program for controlling the normal copying action of this device. The CPU 30 outputs the control signal of sucking action by suction fans 23a, 23b to a driving circuit 37 according to the detected state of a transfer material detecting sensor 17 and the quality of transfer material from a material quality setting part 35. The driving circuit 37 switches the timing of on-off action of the suction fans 23a, 23b. The CPU 30 judges whether the quality of the transfer material P set by an operator in the material quality setting part 35 is ordinary paper and performs suction control according to the material quality. The generation of wrinkles and image slippage to the transfer material can be thereby prevented effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer material for transferring a transfer material on which a toner image is transferred from an image transfer portion to a fixing device in an image forming apparatus such as a copying machine or a printer using electrophotography. The present invention relates to a transfer device, and more particularly to a transfer material transfer device in which a guide member (chute member) is provided immediately before a fixing device and guides the fixing member along the guide member.

[0002]

2. Description of the Related Art Generally, in an apparatus such as an electronic copying machine or a laser printer for making a recording paper by using a xerographic method, a toner image formed on a photosensitive drum is transferred onto a transfer material such as paper, The transfer material on which the toner image is transferred is guided to the fixing device by a conveyor belt or the like. Then, in this fixing device, the toner is fixed on the transfer material to complete the recording paper.

Conventionally, as a fixing device, an actual Kaihei 2-13 is used.
A heating roller system such as that disclosed in Japanese Patent No. 6273 (fixing device for image forming apparatus) is used. In this heat roller fixing device, a heating roller having a heater (heating lamp) built therein is pressed with a predetermined pressure to a heating roller having a metal pipe whose surface is covered with an elastic member such as silicon rubber. The fixing is performed by nipping the transfer material between the roller and the roller and applying heat and pressure.

By the way, in order to convey the transfer material from the image transfer portion to such a fixing device, suction means as disclosed in, for example, Japanese Utility Model Laid-Open No. 2-89459 is provided on the downstream side of the photosensitive drum. The belt conveyor used is provided. In this belt transport device, the back surface of the transfer material on which the toner image is formed is sucked toward the belt side, and the transfer material is directed toward the nip portion between the heating roller and the pressure roller of the fixing device by friction with the belt. It is designed to be transported.

However, when the transfer material is conveyed using such a belt conveying device, the transfer material may absorb moisture depending on the installation environment of the device. If the moisture absorption is high, the tip of the transfer material may be wavy in the width direction. When the transfer material is nipped between the heating roller and the pressure roller to be fixed while curving as described above, there is a problem that wrinkles occur in the transfer material after fixing and the copy quality is deteriorated.

Various methods have hitherto been taken in order to prevent the generation of wrinkles on the transfer material. For example, in Japanese Utility Model Laid-Open No. 60-39050, the tip end of a guide member arranged near the upstream side of the fixing device is formed in an arc shape, and the tip end of the central part is a nip between a heating roller and a pressure roller. Disclosed is a configuration in which it is projected so as to be close to the portion. That is, by inserting the central portion of the transfer material into the nip portion before the both end portions, it is intended to prevent the transfer material from wrinkling. As a modified example of such a method, the heating roller is formed in a wrapping shape in the axial direction, and the pressure roller is formed in a drum shape corresponding to the wrapping shape, so that the center portion of the transfer material is formed at both ends. Some of them are designed to be inserted into the nip portion before the portion to prevent the generation of wrinkles.

However, in any of these methods, when the transfer material is conveyed at a high speed, the entire width direction of the transfer material is not pressed by the guide member. Therefore, there is a problem in that the transfer material cannot be conveyed along the guide member, and the occurrence of wrinkles cannot be reliably prevented.

Therefore, as a means for solving such a problem, conventionally, a method is provided in which a cylindrical suction guide member is provided between the belt conveying device and the fixing device, and the transfer material is sucked and brought into close contact and conveyed (Patent Publication No. 3). No. 20748), or a method of providing a transfer material suction fan below the belt transfer device and suctioning and adhering the transfer material (Japanese Patent Publication No. 4-32454).

Further, the leading end of the guide member on the upstream side of the fixing device is made to face the lower position of the heating roller arranged above in the fixing device, and the transfer material is once abutted against the heating roller from the upper surface of the guide member. Then, there is also a method in which the wrinkles are prevented by changing the direction and guiding the transfer material to the nip portion between the heating roller and the pressure roller to iron the transfer material.

Further, a guide member disposed between the conveying device provided with the suction means and the fixing device is arranged so as to be inclined upward toward the nip portion of the fixing device, and the suction means is attached to the guide member. There is also one in which the transfer material is forcibly brought into close contact with the guide member and guided in a sliding state, thereby preventing wrinkling of the transfer material (Japanese Patent Application No. 3-60931).

[0011]

However, the material of the transfer material conveyed by such a conveying device is as follows.
In addition to plain paper, there are various types such as tracing paper and film, and the size ranges from wide such as A0 size to narrow such as A4 size. Furthermore, the thickness of the transfer material ranges from thick paper to thin paper such as Japanese paper. There are many types of transfer materials conveyed in this way, and as described above, the method of uniformly adhering to the guide member regardless of the type of transfer material causes wrinkles and image shifts. It was not enough to prevent it.

The present invention has been made in view of the above problems, and an object thereof is to prevent the occurrence of wrinkles and image shifts of a moisture-absorbed transfer material regardless of the type of the transfer material, the size, and the like. An object of the present invention is to provide a transfer material transport device that can perform such transfer.

[0013]

According to a first aspect of the present invention, there is provided a transfer material conveying device for conveying a transfer material having a toner image transferred from an image carrier to a fixing device, and a transfer material in a conveying direction. And a plurality of suction holes are formed in a direction orthogonal to each other, and a guide member for guiding the transfer material conveyed by the conveying means along the upper surface to the fixing device, and arranged below the guide member. At the same time, the suction means for sucking the transfer material moving on the upper surface of the guide member to bring it into close contact with the guide member, and the operation timing of the suction means according to the type of the transfer material are at least the tip portion of the transfer material and And a control means for switching so that the rear end portion is sucked.

In this transfer material conveying device, a suction device is provided for the guide member between the fixing device and the conveying means, and the operation timing of this suction device depends on the type (material, etc.) of the transfer material. Since switching is performed and appropriate suction control is performed for each transfer material, it is possible to effectively prevent wrinkles and image shifts.

According to a second aspect of the present invention, there is provided a transfer material transporting device for transporting a transfer material on which a toner image is transferred from an image carrier to a fixing device, and a plurality of transporting means in a direction orthogonal to a transporting direction of the transfer material. And a guide member for guiding the transfer material conveyed by the conveying means to the fixing device along the upper surface thereof, and a guide member disposed below the guide member. Suction means for sucking the transfer material moving on the upper surface to bring the transfer material into close contact with the guide member, means for substantially equalizing the suction distribution by the suction means in the direction orthogonal to the conveying direction of the transfer material, and the transfer material. And a control means for switching the operation timing of the suction means depending on the type of the suction means so as to suck at least the front end portion and the rear end portion of the transfer material.

In this transfer material conveying device, the operation timing of the suction device is switched in accordance with the type (material, etc.) of the transfer material, and the suction distribution is made uniform, so that it is more reliable than in the first aspect. It is possible to prevent wrinkles and image shifts from occurring.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a transfer material conveying apparatus according to an embodiment of the present invention. This transfer material transport device
From the image transfer portion of the photosensitive drum 11 as an image carrier,
The transfer material P is conveyed to the fixing device 26.

The photosensitive drum 11 rotates at a constant peripheral speed in the direction shown by an arrow in the figure, and a toner image formed by a charging corotron and a developing device (not shown) is discharged by a transfer corotron 12 arranged oppositely. Transfer to the transfer material P. The transfer material P on which the toner image is transferred is peeled off from the surface of the photoconductor drum 11 by the discharge of the peeling corotron 13.

The fixing device 26 comprises a heating roller 24 having a built-in heater 24a, and a pressure roller 25 which is arranged to face the heating roller 24 and is pressed against the heating roller 24 with a predetermined pressure. It is configured.
The transfer sheet P is nipped between the heating roller 24 and the pressure roller 25 and heat and pressure are applied to the transfer sheet P to fix the transfer sheet P. The transfer paper P on which the toner image is fixed is discharged to a discharge tray (not shown).

The transfer material conveying device of the present embodiment is a suction conveying device 14 which is horizontally arranged on the downstream side of the photosensitive drum 11.
And a guide member 20 arranged between the suction and conveyance device 14 and the fixing device 26.

The suction / conveyance device 14 comprises a driving roller 15a and a driven roller 15b which are arranged to face each other, and a plurality of conveyor belts 16 wound between the rollers 15a and 15b. With the rotation in the direction indicated by the arrow in FIG.
The transfer material P is conveyed to the fixing device 26 side by the friction with. Although not shown, the transport belt 16 has a large number of suction holes. A plurality of suction devices 18 each having a suction fan 19 are provided below the transport belt 16 in a direction orthogonal to the transport direction of the transfer material P (perpendicular to the paper surface, hereinafter referred to as width direction). For example, three are installed side by side. The transfer material P conveyed by the conveyor belt 16 is brought into close contact with the surface of the conveyor belt 16 by these suction devices 18 to prevent the occurrence of waviness.

A transfer material detection sensor 17 is arranged on the upper surface (transfer material transfer path) of the transfer belt 16 so as to detect the leading end and the trailing end of the transfer material P.

The guide member 20 is disposed so as to be inclined between the suction conveyance device 14 and the fixing device 26, and the fixing device 26 is provided.
The one end portion of the side is disposed slightly on the heating roller 24 side from the nip portion. That is, the transfer material P conveyed on the upper surface of the guide member 20 once hits the heating roller 24 side and is then inserted into the nip portion between the heating roller 24 and the pressure roller 25.

As shown in FIG. 2, the guide member 20 is arranged in parallel with the pressure roller 25 of the fixing device 26, and is set to have substantially the same length as the pressure roller 25.
A suction device 21 is arranged below the guide member 20. Inside the suction device 21, in the width direction of the guide member 20,
The two suction fans 23a and 23b are housed so as to be symmetrical with respect to the center line of the guide member 20. A suction duct 22 is provided between the suction fans 23a and 23b and the guide member 20.

A large number of suction holes 27 are formed in the guide member 20, for example, in two rows. The intervals of these suction holes 27 are set so that the suction holes 27 at positions facing the suction fans 23a and 23b are in a coarse state, while the suction holes 27 at positions away from the suction fans 23a and 23b are in a dense state. Has been done. This makes the suction distribution by the suction fans 23a, 23b uniform.

The suction hole 27 may have any shape such as a circular shape, but it is necessary to prevent the transfer material P traveling on the upper surface of the guide member 20 from being caught as much as possible. Therefore, the suction holes 27 are formed by burring holes, and the positions thereof are the transfer material P for all sizes such as A0 and A4 sizes.
It is desirable to set such that both end surfaces of the above do not face the suction holes 27, respectively.

FIG. 3 shows the cross-sectional shape of the guide member 20. The guide member 20 is formed in an arc shape having a radius R (for example, 24618 mm) in the width direction. That is, with the transfer material P along the upper surface of the guide member 20, the transfer material P is curved so that the central portion is high and both sides are low, and in this state, the transfer material P is directed toward the nip portion of the fixing device 26. It is supposed to guide you.

FIG. 4 shows the configuration of the control unit of the image recording apparatus of this embodiment. The control unit includes a CPU (central processing unit) 30. The CPU 30 is connected to each unit of the device via a bus 31. Of these, ROM
The (read only memory) 32 stores a suction control program as shown in a flow chart (FIG. 5) described later as well as a program for controlling a normal copying operation of this apparatus. RAM (random access memory) 3
Various calculation results and data are temporarily stored in 3. The input port 34 is the transfer material detection sensor 1
7 is an interface for sending the detection signal of No. 7 and the material data output from the material setting unit 35 to the CPU 30.

In the material setting section 35, as the transfer material P, three kinds of materials such as plain paper, tracing paper and film can be set. CPU3
0 controls the suction operation by the suction fans 23a and 23b according to the detection state of the transfer material detection sensor 17 (front end detection and rear end detection) and the material of the transfer material P. The output port 36 is an interface for sending the control signal sent from the CPU 30 to the drive circuit 37. The drive circuit 37 switches the timing of on / off operation of the suction fans 23a, 23 according to a control signal output from the CPU 30.

In this embodiment, the transfer material P is sent to the image transfer portion of the photoconductor drum 11 by a conveying means (not shown), and the toner image is transferred from the photoconductor drum 11 by the discharge of the transfer corotron 12. After that, the transfer material P
Is peeled from the photoconductor drum 11 by the discharge of the peeling corotron 13. The transfer material P separated from the photoconductor drum 11 is transported by the transport device 14, and is further guided by the guide member 20.
Is guided to the nip portion between the heating roller 24 and the pressure roller 25 of the fixing device 26, and the toner image is fixed by passing therethrough, and then discharged to a discharge tray (not shown).

Next, the suction control operation by the suction device 21 will be described with reference to the flowchart of FIG.

First, the CPU 30 determines whether or not a start switch (not shown) has been pressed (step S50).
0), when pressed (Y), the suction fans 23a, 2
3b is driven to start the suction operation (step S5
01). In this state, the leading end of the transfer material P is conveyed by the suction conveyance device 14 and is guided while closely adhering to the upper surface of the guide member 20, and once hits the lower portion of the heating roller 24, then the heating roller 24 and the pressure roller. 25 is fed to the nip position between the two. Next, the CPU 30 determines whether or not the material of the transfer material P set by the operator in the material setting unit 35 is plain paper (step S502), and performs suction control according to the material as shown in the following table.

[0034]

[Table 1]

That is, when the transfer material P is plain paper (step S502; Y), it is determined whether or not the leading edge of the transfer material P is detected by the transfer material detection sensor 17 provided on the suction conveyance device 14. It is determined (step S503), and it is further determined whether or not X seconds have elapsed from the time when the leading edge of the transfer material P is detected by the built-in timer (step S50).
4). Here, X is 2.3 (seconds) in this embodiment.
This numerical value is a value corresponding to the time from when the leading edge of the transfer material P is detected by the transfer material detection sensor 17 to when it reaches the nip position of the fixing device 26.

X seconds have passed, that is, the leading edge of the transfer material P reaches the nip position of the fixing device 26 (step S504;
If Y), the CPU 30 temporarily stops driving the suction fans 23a and 23b (step S505). That is, the suction by the suction fans 23a and 23b is stopped while the intermediate position of the transfer material P is located on the upper surface of the guide member 20.
Subsequently, the CPU 30 detects the front end of the transfer material P by the transfer material detection switch 17, and then ((length of transfer material) ÷
[Process speed] -Y) It is determined whether or not seconds have elapsed (step S506). For example, if the process speed is 76.
When the length of the transfer material is 2 mm / sec and the length of the transfer material is 1189 mm (A0 size), the above time is 14.6 sec. CPU3
When 0 has passed this time (Y), the suction fan 23
The driving of a and 23b is restarted (step S507).
As a result, the rear end portion of the transfer material P is again guided while being in close contact with the upper surface of the guide member 20.

Next, the CPU 30 determines whether or not the start switch has been turned off (step S508), and if it remains on (N), the process proceeds to step S502,
Similar to the above-described operation, the suction control of the next transfer material P is performed. When the start switch is turned off (Y), driving of the suction fans 23a and 23b is stopped (step S50).
9). In step S502, since the transfer material P is made of a material other than plain paper, that is, thinner than plain paper, waviness is likely to occur due to moisture absorption, and a suction operation is more necessary.
In the case of tracing paper or film (step S502; N), the transfer material P is conveyed while being sucked over the entire length thereof.

As described above, in this embodiment, in the guide member 20, depending on the material of the transfer material P, the suction fan 23a,
Since the suction operation by 23b is switched, stable transfer can be performed for each transfer material P. Therefore, in combination with the curved shape of the guide member 20 (FIG. 3) and the like, the occurrence of wrinkles and image shift can be effectively prevented. Further, in this embodiment, since the suction distribution by the suction device 21 is made uniform, this effect can be further exerted.

The present invention has been described with reference to the examples.
The present invention is not limited to the above-described embodiments, but can be variously modified without departing from the scope of the invention. For example, in the above-described embodiment, the suction operation of the suction device 21 under the guide member 20 is switched according to the material of the transfer material P, but the suction fans 23a, 23b according to the size (length) of the transfer material P. The on / off timing of may be switched. Moreover, you may make it use these together. Further, the number of suction fans may be increased in the width direction of the transfer material P, and the suction fans may be selectively operated according to the width of the transferred transfer material P.

Further, in the above embodiment, as a means for making the suction distribution uniform, a plurality of suction fans are provided under the guide member 20, and the density of the suction holes 27 provided in the guide member 20 is changed according to the fan position. However, as another method, a shielding plate or the like may be provided in the suction duct 22 to control the suction distribution.

Although the operation control of the suction device 21 in the guide member 20 has been described in the above embodiment, the operation of, for example, the central fan 19 among the three suction fans 19 in the suction conveyance device 14 is transferred. You may make it control according to the kind of material P. The following table shows an example of control when the size of the transfer material P is A0. The basic operation is the same as in the above embodiment, but in this case, the transfer material P
In the operation after the tip of the transfer material detection switch 17 is turned on and the suction fan 19 is stopped after X seconds, unlike the step S506 (FIG. 5), the tip of the transfer material P is simply the transfer material detection switch. Y seconds after turning on 17,
The suction fan 19 is driven again. After that, the transfer material P is sucked up to the rear end portion. When X> Y, Y is given priority, that is, the transfer material P is sucked over the entire length from the front end to the rear end.

[0042]

[Table 2]

Further, in the above embodiment, the suction operation of the transfer material P is switched by the on / off operation of the suction fans 23a and 23b.
The suction control may be performed by selectively closing 7 with a shielding mechanism using a solenoid or the like.

[0044]

As described above, according to the transfer material conveying device of the first aspect, the suction device is provided for the guide member between the fixing device and the conveying means, and the operation timing of the suction device is transferred. Since switching is performed according to the type of material, appropriate suction control is performed for each transfer material, and wrinkles and image shifts can be effectively prevented.

Further, according to the transfer material conveying device of the second aspect, the operation timing of the suction device is switched according to the type of the transfer material and the suction distribution is made uniform.
The occurrence of wrinkles and image shifts can be prevented more reliably than in the first aspect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a transfer material transport device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a suction device below a guide member in the transfer material transport device of FIG.

3 is a cross-sectional view of the guide member taken along the line AA of FIG.

FIG. 4 is a block diagram showing a configuration of a control unit of the transfer material transport device of FIG.

5 is a flowchart for explaining the operation of the transfer material transport device of FIG. 1. FIG.

[Explanation of symbols]

11 ... Photosensitive drum (image carrier), 12 ... Transfer corotron, 14 ... Suction / conveyance device, 16 ... Conveyance solenoid, 19
... Suction fan, 20 ... Guide member, 21 ... Suction device, 22
... suction duct, 23a, 23b ... suction fan, 24 ... heating roller, 25 ... pressure roller, 26 ... fixing device, 27 ...
Suction hole

Claims (2)

[Claims] 1. A conveying unit configured to convey a transfer material, on which a toner image is transferred from an image carrier, to a fixing device, and a plurality of suction holes are formed in a direction orthogonal to a conveying direction of the transfer material, A guide member that guides the transfer material conveyed by the conveying means to the fixing device along the upper surface, and a transfer member that is arranged below the guide member and that moves on the upper surface of the guide member is sucked. And a control means for switching the operation timing of the suction means according to the type of the transfer material so as to suck at least the front end portion and the rear end portion of the transfer material. A transfer material conveying device characterized by the above. 2. A conveyance unit configured to convey a transfer material, on which a toner image is transferred from an image carrier, to a fixing device, and a plurality of suction holes are formed in a direction orthogonal to a conveyance direction of the transfer material, A guide member that guides the transfer material conveyed by the conveying means to the fixing device along the upper surface, and a transfer member that is arranged below the guide member and that moves on the upper surface of the guide member is sucked. Suction means for closely contacting with the guide member, means for making the suction distribution by the suction means substantially uniform in the direction orthogonal to the transport direction of the transfer material, and the suction means of the suction means depending on the type of the transfer material. A transfer material conveying device, comprising: a control unit that switches an operation timing so that at least a front end portion and a rear end portion of the transfer material are sucked.