JPS6149661B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device applied to a transfer type electronic copying machine, and particularly to a transfer device suitable for use in a color copying machine.

In conventional color copying machines, in order to superimpose a powder image formed on a photoreceptor onto transfer paper, the transfer paper is wound around a transfer roller and transfer is performed three or four times. This method is based on the so-called roller transfer method, and when transfer is performed multiple times, a so-called hollow phenomenon occurs in which it becomes difficult for the next toner to adhere to the area where the previous toner image was. . Furthermore, when the transfer paper is charged and attracted to the roller, due to changes in the resistance of the transfer paper, it becomes difficult to wrap around the transfer roller when the humidity is high, and poor transfer tends to occur when the humidity is low. Therefore, the roller transfer method has many disadvantages in obtaining a final image of good quality with good color balance.

There are also problems in the device configuration and use. For example, in a copying machine that uses transfer paper of different paper sizes, if a small size transfer paper is used, the toner on the image drum will stick to the transfer roller in the area where there is no paper, and the next large size transfer paper will be transferred. When using paper,
This area can cause stains on the back side, and the transfer electric field can become uneven, causing uneven transfer, so a means to clean the transfer roller is essential, and this cleaning means must be operated when there is no transfer paper. It is very troublesome.

In view of the above points, an object of the present invention is to provide a transfer device that enables good multiple overlapping transfer. Another object of the present invention is to provide a transfer device that always performs good transfer when performing multiple transfers onto a transfer material.

A transfer device of the present invention that achieves the above object is a device that transfers a developed image formed on an image carrier to a transfer material multiple times to form an image on the transfer material, and comprises:
a transfer material conveying means having a gripping means for gripping the leading end of the transfer material, and endlessly conveying the transfer material gripped by the gripping means to a transfer position; and the above-mentioned conveyance means moving opposite to the image carrier. a transfer corona means that is fixedly arranged inside the movement path of the transfer means and applies a corona discharge for transfer to the transfer material that is transported by the transport means and passes through the transfer position; and a movement of the transfer material that is transported by the transport means. The roller means is provided along the moving path of the conveyance means to regulate the movement of the conveyance means, and has a pair of roller means that are not in contact with each other.

The details of the present invention will be explained below using specific examples with reference to the drawings.

FIG. 1 shows a side view of an embodiment of an electrophotographic copying machine using a transfer device according to the present invention. To explain its operation, the original on the document platen glass 1 is integrated with the first scanning mirror 4. The reflected light is irradiated by the illumination system (the yaw lamp 3 and the reflective shade 2), and the reflected light is transmitted to the first scanning mirror 4 and the second scanning mirror 5.
is scanned with. The first and second scanning mirrors are 1:
By moving at a speed ratio of 1/2, the lens system 6 scans the original. The reflected light image passes through the lens 6 and reaches the color separation filter 7, which separates the light images into three colors 7a, 7b, and 7c corresponding to red (R), green (G), and blue (B). The colors are separated by one of the filters. This color-separated light image is
The image is formed on the photosensitive drum 14 via the mirror 8, the fourth mirror 9, and the dust-proof sealed glass 10. The photosensitive drum 14 is rotatably supported on a shaft 14, rotates in the direction of the arrow, is charged (for example, +) by the primary charger 13, and is then charged with AC or AC while being irradiated with the color-separated optical image. Static electricity is removed by a static eliminator 11 having a polarity opposite to that of the primary one (for example, -), and the entire surface is uniformly irradiated with a full-surface exposure lamp 54 to obtain a high-contrast electrostatic latent image.

The electrostatic latent image on the photosensitive drum 14 is then transferred to the developing device 1.
Visualized by 5. The developing device 15 is composed of four developing devices 15a, 15b, 15c, and 15d for cyan (C), magenta (M), yellow (Y), and black. For the filter 7c, the yellow developer 15c) rotates to the developing position and performs development. Transfer paper P in the cassette is transferred to paper feed roller 1.
7 into the machine, and the timing roller 18
-1 takes the first timing and is further fed by the feed roller 18-2, and the timing roller 1
At step 8-3, the transfer paper is fed into the opening of the gripper 101 with even more accurate timing, and the opening is closed at the position where it is removed from the cam 102, and the leading edge of the transfer paper is gripped.

Next, while the transfer paper P passes between the transfer corona discharger 127 and the photosensitive drum 14, the developed image on the photosensitive drum is transferred onto the transfer paper. In the case of color, the gripper rotates three times while gripping the transfer paper P,
Separation claw 24 after three-color transfer and gripper opening cam 1
04 is activated, releasing the transfer material from the gripper,
Guided by the conveyor belt 25, the fixing roll pair 1
The transferred image is guided to 9a and 19c and heated, and the transferred image is fixed and discharged.

Also, after transferring the developed images of each color, the photosensitive drum 1
4 cleans the surface with a cleaning device composed of an elastic blade and enters the next cycle.

Since the transfer device of the present invention applied to the above-described copying machine grips only the leading edge of the transfer paper, the portion other than the leading edge of the transfer paper onto which the developed image has been transferred is held by the claws 24 disposed around the transfer unit 109. , the guide 107, the developing device 15d, etc., to prevent the transferred image from being rubbed, and also to configure the portions other than the leading edge of the transfer paper to draw a shape almost similar to the trajectory drawn by the leading edge. This solves the problem of registration errors and wrinkles and creases in the paper during production.

Conventionally, transfer paper is held and transported by suction and a belt suspended from the suction part, but with such a device, when transporting thick letters in an arc, Since it is strong, considerable suction ability is required. Furthermore, it is impossible to hold and transport thick materials, such as cardboard. On the other hand, if thin paper is passed through a device adjusted for thick paper, it will stick too much and wrinkle, resulting in uneven transfer after multiple transfers. In addition, using the adsorption force due to electrostatic corona,
Furthermore, the image may be disturbed due to the influence of the atmosphere and uneven charging.

In this example device, rollers that rotate at approximately the same circumferential speed as the moving speed of the transfer paper are provided at several locations on the transfer paper path to restrict arbitrary movement of the transfer paper and form a guide for the transfer paper. .

Therefore, even if there is a change in speed due to differences in stiffness depending on whether the transfer paper is thick or thin or due to external force in the part that grips the transfer paper in the part without the roller, it can be absorbed by the free part other than the roller. Therefore, it can respond to changes in transfer paper thickness and speed. Further, since the roller pair is not in contact with each other, there is no pressure applied to the transferred image, and there is almost no possibility that toner will adhere to the roller. Furthermore, even if dirt adheres to the outer roller, it will not be offset to the inner roller, so it will not adhere to the transfer paper.

As shown in FIG. 2, the transfer device section is a roller 1.
05 and 106, after the gripping mechanism at the leading edge of the transfer paper passes through the gap between the rollers, it pinches the portion of the transfer paper that is not gripped to prevent the transfer paper from moving freely. The gap between the pair of rollers is preferably thicker than the paper thickness, and is allowable up to approximately 6 m/m. There is no need to specify the material of the inner roller as it does not directly touch the powder image on the transfer paper, but if a grounded conductor, such as a metal roller, is used, the toner image on the transfer paper will repel at extremely low humidity. There is a possibility that it will fly. Therefore, rubber rollers, or even rollers with knurling, are suitable from the standpoint of transmitting the conveying force. Since the outer roller 105 may come into contact with the transferred image, a non-adhesive material such as Teflon, Delrin, Rulon (trade name), or a metal roller to which a high potential of the same polarity as the toner is applied may be used. The entire transfer paper is covered with roller pair 105-
1,105-2, only the rear end of the transfer paper P comes into contact with the arcuate claw 24 on its belly surface and moves. Since only the rear end contacts and moves while sliding, the transferred image is not destroyed at all. Similarly guide 11
0, the transfer paper moves with only the trailing edge in contact,
Further, the trailing edge of the transfer paper passes through the roller pair 105-3, 106-3.

Next, after paper feeding is completed, the trailing edge of the transfer paper moves on the guide 107-2 attached to the upper surface of the paper feed guide 107, which has been moved to the position indicated by the dotted line by plunge shearing or the like, in the same manner as on the other guides mentioned above.

The transfer paper guided to the transfer position again is moved by spring members 111-1 and 111 that act as a force to press the transfer paper against the copying drum in order to extend the contact distance with the photoreceptor.
-2 and is brought into contact with the photoreceptor, and transfer is performed without uneven transfer. Also, this spring material is used for the span portion 109-1 of the transfer unit as shown in the figure.
Since it is fixed on the escape side with respect to the passage of the part, it escapes in response to the passage of the part, so no separate driving means is required.

With the mechanism described above, when the gripper is opened by the gripper opening cam 102-2, the transfer paper holding the transferred images multiple times is separated at the same time because the transfer paper is gripped in a structure that easily lifts up, as will be described later. When the claw 24 is swung to a position indicated by the dotted line where it does not come into contact with the transfer unit, the transfer paper is suddenly released from the cylindrical state, the transfer paper is naturally placed on the claw, and the feeding force of the roller 106-1 moves the transfer paper to the transfer unit. It is then discharged and sent to the fixing process.

FIG. 2a is an enlarged view of the gripper portion shown in the second diagram. The gripper 101, which is supported by a shaft 101-2 and is always biased in the direction of pinching the transfer paper by a torsion spring 101-3, has a structure that will be described later. When the cam 102-2 moves and a point is pressed on the circumferential surface of the cam, the gripper 101 rotates counterclockwise around the shaft 101-2, releasing the transfer paper or
Ready to pinch. The transfer paper P whose point is removed from the circumferential surface of the cam 102-2 and whose tip is gripped is pressed inside the cylindrical outer periphery of the transfer unit 109, and the gripper itself also supports the transfer paper inside the cylindrical outer periphery. As a result, the force of the stiffness of the paper creates a force that makes it look like a dotted line, and it becomes pressed against the photosensitive drum, allowing good transfer from the leading edge.Furthermore, when the gripper is opened, the stiffness of the transfer paper Since the tip jumps up using the point as a node, it is also advantageous in separation. Further, the transfer paper is structured to be bent suddenly at a position near the gripper and on the circumference of the unit 109. The circumferential radius of the unit is equal to or in an integral ratio with the circumferential radius of the photosensitive drum, and the gear 122 has a pitch circle diameter approximately equal to the circumferential radius of the photosensitive drum.
Since the gears 144, which have a pitch diameter approximately equal to the circumferential radius of the transfer unit, are mechanically directly connected to each other, a predetermined circular conveyance path is taken each time for several transfers to transfer each developed image on the photosensitive drum. is aligned in precise synchronization with the leading edge of the transfer paper and mechanically contacts it through the transfer paper. As a result, a transferred image with no color shift can be obtained.

This will be explained in more detail with reference to a perspective view of the transfer device section shown in FIG. 3 and a sectional view thereof in FIG. The transfer unit 109 is integrally screwed to the central shaft 103 via a plate 123, and a gear 114 connected to the central shaft meshes with a gear 122 connected to the photosensitive drum (not shown). Gears 114 and 122
The gear ratio is 1/1 or an integer ratio. As a result, the point of the transfer unit 109 is aligned at the same position at the leading edge of the image on the photosensitive drum without any deviation during one rotation of the photosensitive drum. In addition, in this type of device, various mechanisms such as a gripper opening cam, an inner roller 106 for paper regulation, and a charger 103 are installed inside the transfer unit 109, so a special method for supporting the cylindrical transfer unit is required. A method is needed. In this device, in order to drive the inner roller and the gripper opening cam 102-
In order to take the moving mechanism 2, 102-3 out of the unit, the inner peripheral surface of the unit is supported by three shafts 118 fixed to the machine side plate and rollers 119 rotatably attached to the shafts. The other end of the unit is fixed to the central shaft 103 via a plate 123, and this shaft is rotatably supported by a machine side plate with a bearing.

As a result, the driving force of the gear 114 is integrally transmitted to the transfer unit 109. Also, Koro 119
The shaft of the inner roller 106 can be brought out of the side plate through a space other than the central shaft 103, and the inner roller 106 can be driven via the gear 113 that rotates the outer roller 105. Furthermore, when the inner roller 106 passes through the span section 109-1 of the transfer unit, the outer periphery of the roller is close to the outer circumference of the unit.
The roller 106-2 of the cam 112, which is fitted corresponding to that part of the span, rides up so as not to obstruct the passage of the span, and a gap larger than the thickness of the span is generated between the two rollers 105 and 106. From the rear cam, both rollers are connected by springs 121.
It returns to its original position due to its elastic force.

Bearing 120-1 that supports one end of the inner roller
is engaged with the side plate 125, but the bearing 120-2 supporting the other end is connected to the side plate 125 by the stay 118.
It is engaged with an auxiliary side plate 124 which is cantilevered from the center and supported by a bearing so as not to rotate with respect to the central axis.

FIG. 5 is a perspective view of the transfer unit, which consists of a plate 123 that fixes the unit 109 to the rotating central shaft 103, a span section 109-1, a runner groove 109-2 in which three rollers run, and other components to release the transfer corona. For electrical appliances, there is a gap 109 between the plate 123 and the unit 109.
-3 can be inserted and removed.

FIG. 6 illustrates a different method of supporting the transfer unit. In this method, the central axis can be fixed or eliminated.

The transfer unit 109 has one end supported by a bearing 129 fitted to a member 131 fixed to the side plate 126, and the other end supported by a shaft 1 fixed to the side plate 125.
03 is rotatably supported by a bearing 130 fitted in the bearing 130. The discharger is rail 127-2,
Members 131 and 1 supported by respective side plates
03, and the discharger is located in hole 1 of member 131.
It can be freely inserted and removed from 31-2. The inner roller 106 shows a state in which the rollers are separated, but the shaft 106-3 is taken out of the unit 109 and is attached to the transfer unit gear 113.
are engaged and when the inner roller roller 106-2 is disengaged from the cam 112, the inner roller gear 10
3-2 and the lower roller gear 115 mesh to drive the inner roller.

By the way, in a color copying machine like this apparatus, the gripper opening cam 102-2 opens to grip the leading edge of the transfer paper during the first paper feeding, and does not open the gripper until the third transfer is completed. However, since the transfer unit support method described above is adopted, the cam 102-2 must be moved to the central axis 103.
It is easy to slide the upper part through the bearing 102-3 and release it. That is, in order to slide the same number of gripper opening cams 102-2 as the grippers 101, the stay 117 with the cams attached is taken out of the side plate 125 by passing between the rollers 106-2, and the arm 116 is attached. SOL
1 and 2, the stay 117 is moved so that the cam 102-2 can be moved to the gripper open position and the position where it does not hit the gripper.

In the embodiment described above, the outer roller 105 is supported by the side plates 125 and 126 via bearings, and is supported at a position where the roller does not touch even when passing through the span of the transfer unit. Therefore, the peripheral speed of the pair of rollers 105, 106 can be maintained at the same speed as the peripheral speed of the transfer unit. In general, the adhesion force of the toner image on the transfer paper is due to the electrostatic force between the toner charge and the charge in the transfer paper, and it is relatively resistant to force in the direction of the thickness of the transfer paper, but in the direction perpendicular to that force. That is, since it is extremely weak against force in the sliding direction, if the roller and the transfer paper slip, the transferred image is likely to be destroyed. However, in this device, the inner and outer rollers are driven mechanically and stably, so the toner image is not disturbed. Furthermore, even if load fluctuations occur on the transfer unit, since there is a gap between the pair of guiding rollers, no load will be applied to the transfer paper, and the transfer paper will be stably fed by the electrostatic force with the photosensitive drum.

As mentioned above, a cylindrical transfer unit has been described as a specific example, but it goes without saying that a structure in which the transfer paper grip is moved along a predetermined path using a chain or the like can also be realized.

As described in detail above, the apparatus of the present invention is extremely excellent in that it can perform good transfer even if transfer is repeated multiple times onto a transfer material. Furthermore, the apparatus of the present invention is extremely effective because it enables superimposed transfer without disturbing the transferred images.

[Brief explanation of the drawing]

FIG. 1 is a side view of a copying device using a transfer device according to the present invention, FIG. 2 is a side view of a transfer device which is an embodiment of the present invention, FIG. 2a is a partially enlarged view thereof, and FIG. 3 is an implementation FIG. 4 is a sectional view of the example device, FIG. 5 is a perspective view of the transfer unit, and FIG. 6 is a perspective view of the example device.
The figure shows a sectional view of another example device. In the figure, 14...photosensitive drum, 15a, 15
b, 15c, 15d...Developer, 105-1, 1
05-2, 105-3, 106-1, 106-
2,106-3...Regulation roller for transfer paper, 1
09...Transfer material conveying means, 127...Transfer corona discharger.

Claims (1)

[Scope of Claims] 1. A transfer device that transfers a developed image formed on an image carrier to a transfer material multiple times to form an image on the transfer material, comprising a gripping means for gripping the leading end of the transfer material, A transfer material conveying means that endlessly conveys the transfer material gripped by the gripping means to the transfer position; and a transfer material conveying means that is fixedly disposed inside the movement path of the conveying means that moves opposite to the image carrier arrangement, A transfer corona means for applying a corona discharge for transfer to a transfer material being transported and passing through a transfer position; and a transfer corona means provided along a movement path of the transport means for regulating the movement of the transfer material transported by the transport means. A transfer device comprising roller means arranged in a pair and not in contact with each other. 2. The transfer device according to claim 1, wherein the roller means is driven to rotate at the same peripheral speed as the transfer material conveyance means.