JPS63293573A - Transfer device - Google Patents

Abstract

PURPOSE:To surely fix the whole of transfer paper on a transfer drum and to execute stable transfer by providing a fixing means for respectively fixing at least the front end and rear end of the transfer paper on a periphery plane of the transfer drum on the transfer drum. CONSTITUTION:The fixing means 48 for fixing the transfer paper P on the periphery plane of the transfer drum 36 is constituted of a front end fixing means 50 and a rear end fixing means 52. When the front 3nd of the transfer paper P is seized by a gripper 54 of the front end fixed means 50 and the rear end of the transfer paper P comes before a 2nd magnetically attaching part 64 with the rotation of the transfer drum 36, a lever 82 is turned counterclockwise so that a pin 78 separates a magnet 60 from the 2nd magnetically attaching part 54 and the magnet 60 is magnetically attached to a 1st magnetic attaching part 62. Namely, by magnetically attaching the magnet 60 to the 2nd magnetically attaching art 64 on a main body side temporarily at the time of feeding paper and by magnetically attaching the magnet 60 to the 1st magnetically attaching part 62 of the transfer drum 36 when the back end of the transferring paper P comes, the back end of the transferring paper P is seized and fixing by a pressing piece 60a. Therefore the entire transfer paper P is surely fixed on the transfer drum 36.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to a transfer device used in an electrophotographic color printer or the like.

(Prior Art) A known electrophotographic color printer is one in which a transfer paper is wound around a transfer drum and the paper is transferred a number of times depending on the number of colors required. This type of printer normally holds the transfer paper on the circumferential surface of the transfer drum by gripping the leading edge of the transfer paper with the claws of a gripper.

However, even if you hold only the leading edge of the transfer paper in your mouth, when the transfer drum rotates, the trailing edge of the paper will hang down. Preventing you from leaving.

(Problems to be Solved by the Invention) Conventionally, a guide roller or the like is used to fix the rear end of the transfer paper to the transfer drum, so the rear end of the transfer paper cannot be securely fixed. There is a problem in that the trailing edge of the transfer paper becomes wavy and stable transfer cannot be performed.

The present invention has been made based on the above-mentioned circumstances, and its purpose is to provide a transfer device that can securely fix the entire transfer paper to the transfer drum and thereby perform stable transfer. be.

[Structure of the Invention] (Means for Solving the Problem) In order to solve the above problem, the present invention wraps a transfer paper around the circumferential surface of a transfer drum and transfers an image carried on an image carrier. A transfer device for transferring images onto paper is characterized in that the transfer drum is provided with fixing means for fixing at least the leading and trailing ends of the transfer paper to the circumferential surface of the transfer drum.

(Function) At least the leading and trailing ends of the transfer paper are fixed to the transfer drum to eliminate waving of the transfer paper.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 12.

FIG. 11 shows a color printer using the transfer device according to the present invention, and 2 in this figure is the main body. This main body 2
An operating section 4 is provided on the front surface of the printer, and a paper feed cassette 6 is removably attached to the bottom of the negative side. Further, a paper ejection tray 8 is provided above the paper feed cassette 6.

As shown in FIG. 12, a photoreceptor drum (image carrier) 10 that rotates in a predetermined direction is pivotally supported approximately at the center shaft within the main body 2. As shown in FIG. An exposure device 18 having a rotating polygon mirror 12, an fθ lens 14, a mirror 16, etc. is provided above the photoreceptor drum 10, and this exposure device 18 directs a laser beam L containing image information to the photoreceptor drum. 10 for exposure and scanning. Further, around the photoreceptor drum 10, from this exposure position, the photoreceptor drum 10 is
0, a developing device 20, a transfer device 22,
A cleaning device 24, a static eliminator 26, and a charging device 28 are arranged in this order.

The charging device 28 uniformly charges the surface of the photoreceptor drum 10, and the exposure device 18 exposes the charged surface of the photoreceptor drum 10 to form an electrostatic replacement image.

The developing device 20 develops the electrostatic latent image to form a toner image, and has a rotating frame 32 that rotates around a rotating shaft 30 . This rotating frame 32 has a first
-Fourth developing devices 34a to 34d are supported, and as the rotating frame 32 rotates, these developing devices 34a to 34d revolve around the rotating shaft 30 while maintaining a parallel state. Further, each of the developing devices 34a to 34d has toner of a different color, for example, the first developing device 34a has yellow toner, the second developing device 34b has magenta toner, and the third developing device 34a has toner of a different color.
The fourth developer 34c contains cyan toner, and the fourth developer 34c contains cyan toner.
d contains black toner.

The transfer device 22 includes a transfer drum 36 that rolls into contact with the photoreceptor drum 10, and a transfer paper p is placed on the circumferential surface of the transfer drum 36.
to transfer the toner image on the photoreceptor drum 10 onto the transfer paper p.
This is what is transferred onto the top.

A peeling claw 38 for peeling off the transfer paper p wound around the transfer drum 36 is provided around the transfer drum 36.

Further, a bias voltage is applied to the transfer drum 36 during transfer by a voltage applying means (not shown).

The cleaning device 24 removes toner remaining on the photoreceptor drum 10 without being transferred onto the transfer paper p, and the static eliminator 26 removes the residual potential of the photoreceptor drum 10 from which the residual toner has been removed. It is something to do.

Further, a paper feeding device 40 is provided at the bottom of one side of the main body 2.
This paper feeding device 40 feeds the transfer paper p in the paper feeding cassette 6.
Aligning rollers 44, 44 by the paper feed roller 42
The image is supplied to the transfer drum 36 via the transfer drum 36.

Further, above the paper feed device 40, there are provided a fixing device 46 for fixing the toner image onto the transfer paper p, and the paper discharge tray 8 for receiving the transfer paper p after fixing.

After the surface of the photosensitive drum 10 is charged by the charging device 28, an electrostatic latent image to be developed with yellow toner is first formed by the exposure device 18. This electrostatic latent image is developed by the first developing device 34a, and the first color toner image thus formed is transferred onto the transfer paper p wound around the transfer drum 36. Next, photosensitive drum 1
0 has residual toner removed by the cleaning device 24, and then static electricity is removed by the static eliminator 26.

Next, after the surface of the photosensitive drum 10 is charged by the charging device 28, an electrostatic latent image to be developed with magenta toner is formed by the exposure device]8.

The second developing device 34b is opposed to the photosensitive drum 10 after the development of the first color toner image is completed and before the development of the second color toner image is started.

Next, the electrostatic latent image is developed by the second developing device 34b, and the second color toner image thus formed is the same as the first color toner image previously transferred onto the transfer paper p wound around the transfer drum 36. is transferred over the toner image. Then,
After residual toner is removed from the photosensitive drum 10 by a cleaning device 24, the static electricity is removed by a static eliminator 26.

Then, similarly, third and fourth color toner images are sequentially transferred using cyan toner and black toner, thereby forming a full color image on the transfer paper p. Thereafter, the transfer paper p is peeled off from the transfer drum 36 by a peeling claw 38, and then transferred to a fixing device 46.
The image is fixed on the image. The fixed transfer paper p is discharged onto the paper discharge tray 8.

Note that in order to prevent color shift of the first to fourth color images, the timing of the transfer start position is controlled by the exposure timing of the exposure device 18.

As shown in FIG. 1, the transfer device 22 includes a fixing mechanism (fixing means) that fixes the transfer paper p to the circumferential surface of the transfer drum 36.
48, this fixing mechanism 48 includes a leading edge fixing mechanism (leading edge fixing means) 50 that fixes the leading edge of the transfer paper p to the transfer drum 36, and a rear end fixing mechanism (leading edge fixing means) 50 that fixes the leading edge of the transfer paper p to the transfer drum 36. It consists of an end fixing mechanism (rear end fixing means) 52.

The tip fixing mechanism 50 includes a gripper 54 made of a leaf spring, and this gripper 54 is rotatably supported by a shaft 56 that is provided inside the transfer drum 36 and rotates together with the transfer drum 36. Further, this gripper 54 has a grip portion 54a that protrudes and retracts from the opening 38 of the transfer drum 36, and this grip portion 54a
The transfer paper p is fixed to the transfer drum 36 at this point.

The trailing edge fixing mechanism 52 has a magnet 60 equipped with a pressing piece 60a that presses the trailing edge of the transfer paper p against the transfer drum 36. This magnet 60 can be magnetically attached to a first magnetically attached part 62 made of an iron plate provided on the transfer drum 36 and a second magnetically attached part 64 made of an iron plate provided on the main body 2 side. When the transfer paper p is magnetically attached to the first magnetic attachment portion 62, the rear end of the transfer paper p is pressed against the transfer drum 36 by the presser piece 60a. Further, the transfer drum 36 is provided with a first separating mechanism (first separating means) 66, which moves the magnet 60 magnetically attached to the first magnetically attached portion 62 to the first magnetically attached portion 62. It is pulled away from the magnet and magnetically attached to the second magnetic attachment part 64, and has a first pin 68. This first pin 68
is rotatably supported by a pair of levers 72.72 via supports 70, 70, and this lever 72.72 is supported by a shaft 74.74.
are fixed respectively. And the lever 72°72
The first pin 68 rotates counterclockwise.
is adapted to separate the magnet 60 from the first magnetic attachment part 62. On the other hand, a second separation mechanism (second separation means) 76 is provided on the main body 2 side, and this moves the magnet 60 magnetically attached to the second magnetic attachment part 64 The second pin 78 is used to separate the magnetically attached part from the magnetically attached part 62 and attach it to the first magnetically attached part 62 . This second pin 78 is rotatably supported by a pair of levers 82.82 via levers 80, 80, and the levers 82.82 are respectively fixed to shafts 84.84. When the lever 82.degree. 82 rotates counterclockwise, the second pin 78 separates the magnet 60 from the second magnetically attached portion 64.

To further explain the tip fixing mechanism 50, as shown in FIG.
6 in the clockwise direction, so that the gripper 54 comes into contact with the periphery of the opening 58 of the transfer drum 36. Further, this shaft 56 is rotatably attached to a housing 88, and this housing 88 is fixed to a shaft 90. Then, as shown in FIG.
When the gripper 54 rotates clockwise, the gripper 54 is deformed and the grip portion 54a protrudes.

Further, the grip portion 54a of the gripper 54 is pulled into the opening 58 by rotating the shaft 90 in the counterclockwise direction.

As shown in FIG. 5, the magnet 60 is magnetically attached to the center of the transfer drum 36 in the width direction, and the grip portions 54a are provided on both sides thereof. Further, the magnetically attracted position of the magnet 60 and the pressing position of the grip portion 54a are shifted in the circumferential direction of the transfer drum 36.

The first and second pins 68, 78 are connected to holes 62a, 64. The magnet 60 is pushed through a.

As shown in FIGS. 7 and 8, the tip fixing mechanism 50 has a gripper control mechanism 102, which is configured as follows. That is, a lever 104 is integrally fixed to the shaft 90. This lever 10
4 is biased clockwise by a spring 106 and is in contact with a stopper 108 provided on the transfer drum 36 . Further, a midway portion of a lever 110 is rotatably attached to this lever 104 via a lever 112. Cam followers 110 are installed at both ends of this /<-110, respectively.
a and 110b are attached. Further, a lever 114 is fixed to the shaft 56. The cam follower 110b comes into contact with the lever 104 when the lever 110 rotates clockwise, so that the lever 104 rotates counterclockwise together with the shaft 90. On the other hand, when the cam follower 110a/<-110 rotates clockwise, it comes into contact with the lever 114, so that the lever 114 rotates together with the shaft 56.

Also, the cam followers 110a, 1 of the lever 110 are
10b are each moved by one end of a lever 116,118. These levers 116, 118 are connected to the shaft 120
, 122, respectively, and cam followers 11.6a, 118a are attached to the other ends of these levers 116 and 118, respectively. These cam followers 116a and 118a are in contact with cams 126 and 128 attached to the drive shaft 124, respectively.

Thus, when feeding paper, the lever 110 is slightly moved via the cam 124, the lever 116, and the cam follower 110b. As a result, the cam follower 110a, lever 1
14, the shaft 56 is rotated clockwise, and the gripper 5
4 is in the state shown in FIG. 3 above. On the other hand, when discharging the paper, the lever 110 is largely moved via the cam 128, the /<-118, and the cam follower 110b. As a result, the shaft 56 first rotates clockwise, but then the cam follower 110b hits the lever 104, and if the lever 104 is pushed any further, the lever 104 rotates counterclockwise together with the shaft 90. , the gripper 54 is in the state shown in FIG. 4 above.

Further, the peeling claw 38 is fixed to a shaft 130, and this shaft 1
30 is biased by the spring 132, the peeling claw 3
8 is adapted to come into contact with the circumferential surface of the transfer drum 36. Further, a lever 134 is fixed to this shaft 130, and a cam follower 136a at one end of a lever 136 is in contact with this lever 134. This lever 136 is rotatably supported by a shaft 138 at its midpoint, and a cam follower 136b that comes into contact with a cam 140 attached to the drive shaft 124 is attached to the other end. When the shaft 130 is rotated counterclockwise via the cam 140, the lever 136, and the lever 134, the peeling claw 38 is separated from the peripheral surface of the transfer drum 360.

As shown in FIGS. 9 and 10, the rear end fixing mechanism 52 has a pin control mechanism 152, which is configured as follows. That is, one end of a lever 156 is rotatably connected to one of the levers 82 via a shaft 154.

This lever 156 is rotatably attached to a shaft 158,
Further, a cam follower 156a is attached to the other end of this lever 156, which comes into contact with a cam 162 attached to a drive shaft 160. On the other hand, a lever 164 is fixed to one side of the shaft 74, and a cam follower 1648 of this lever 164 moves the transfer drum 36 180 degrees from the position shown in FIG.
When rotated once, it faces one end of the lever 166. The other end of this lever 166 is rotatably attached to a shaft 168. Further, one end of a link 170 is rotatably connected to the middle part of this lever 166 via a shaft 172, and the other end of this link 170 is rotatably connected to a middle part of the lever 174 via a shaft 176. has been done.

One end of the lever 174 is rotatably attached to a shaft 178, and a cam follower 174a that abuts a cam 180 attached to the drive shaft 160 is attached to the other end. During paper feeding, when the transfer drum 36 rotates 180 degrees from the position shown in FIG.
74, link 170, lever 16 via lever 166
4 is rotated counterclockwise. This allows pin 68
pulls the magnet 60 away from the first magnetically attached portion 62 , and the magnet 60 is magnetically attached to the second magnetically attached portion 64 . On the other hand, when the leading edge of the transfer paper p is gripped by the gripper 54 and the transfer drum 36 rotates so that the rear end of the transfer paper P comes to a position slightly in front of the second magnetic attachment part 64, the lever 156 is moved by the cam 162. The lever 82 is rotated counterclockwise through the pin 7.
8 separates the magnet 60 from the second magnetic attachment part 64, and the magnet 60
is magnetically attached to the first magnetically attached portion 62 . As a result, the presser piece 6
The rear end of the transfer paper p is pressed against the transfer drum 36 by 0a.

According to the above configuration, not only the leading edge but also the trailing edge of the transfer paper p is fixed to the circumferential surface of the transfer drum 36, so that the transfer paper p is not undulated and stable transfer can be performed.

Further, the trailing edge fixing mechanism 52 uses the attraction force of the magnet 60 to temporarily attach the magnet 60 to a second magnetically attached portion 64 on the main body 2 side during paper feeding, so that the trailing edge fixing mechanism 52 temporarily attaches the magnet 60 to the second magnetically attached portion 64 on the main body 2 side, and When the edge is attached, the rear end of the transfer paper p is held by the presser piece 60a by magnetically attaching it again to the first magnetic attachment part 62 of the transfer drum 36, so the rear end of the transfer paper p is fixed with a simple structure. be able to.

FIG. 13 shows a first modification of the fixing mechanism 48, and the fixing mechanism 48 in this modification includes a pair of aligning rollers 172a and 172b. One of the aligning rollers 172a is a conductive rubber roller that rolls into contact with the surface of the fed transfer paper p, and the other aligning roller 172b is a metal roller that rolls into contact with the back surface. These conductive rollers 172a and metal rollers 172
A bias voltage is applied to b by a bias power supply 174. Thus, the transfer paper p wound around the transfer drum 36 is charged in advance by passing through the conductive roller 172a and the metal roller 172b. Then, the transfer paper p is attracted and fixed to the transfer drum 36 from the leading edge to the trailing edge by electrostatic force. Note that 176 is a gripper that grips the leading edge of the transfer paper p. Furthermore,
A bristle brush roller made of carbon-containing rayon fiber may be used instead of the conductive roller 172a.

According to such a configuration, in addition to the same effects as in the above embodiment, the transfer paper p is transferred to the transfer drum 36 regardless of the size of the transfer paper p.
can be fixed to.

FIG. 14 shows a second modification of the fixing mechanism 48, in which the fixing mechanism 48 includes a pair of corona chargers 184 disposed between a pair of aligning rollers 182 and a transfer drum 36. have. In addition,
186 is a power source that applies voltage to the corona charger 184. In this case as well, the same effects as in the first modification can be obtained.

FIG. 15 shows a third modification of the fixing mechanism 48, in which the peripheral surface of the metallic transfer drum 36 is coated with a photoconductive material such as a-Si. It is coated with an insulating thin film 192, such as a heat-shrinkable mylar tube. Further, a corona charger 194 for charging the thin film 192 is provided around the transfer drum 36. This corona charger 194
However, it is preferable to use a scorotron charger to prevent the transfer drum 36 from being excessively charged. In this scorotron charger, the thin film is not charged to a potential higher than the potential of the grid 196. When the gripper 176 reaches the lower sheet feeding position, the gripper 176 is opened by a cam mechanism (not shown). At the same time, the paper feed roller 42 is rotated in synchronization with this, and the transfer paper p is transferred to the gripper 17.
I am hit by 6. Next, the gripper 176 is closed, and the leading edge of the transfer paper p is pinched by the gripper 176.

The paper feed roller 42 rotates once and is stopped, and the remaining portion of the transfer paper p is pulled out by the gripper 176 as the transfer drum 36 rotates. Transfer paper p is guide 198, 19
8 and sent to the transfer drum 36, where it is tightly wound. Once wrapped, the electrostatic force, or dipole moment (dipole-IIlome)
nt) due to force F−-grad(εE2) [F: force, ε
: Dielectric constant, E: Adsorbed by electric field etc. Therefore, the rear end of the transfer paper p does not sag due to gravity. It should be noted that charging the transfer paper p further from above causes adverse effects such as bleeding on the image, so charging is performed only for one rotation of the transfer drum 36 on the underside of the transfer paper p. Further, in this transfer step, in addition to the charge on the thin film 192, by applying a bias voltage to the transfer drum 36 in a superimposed manner as necessary, the transfer can be further improved. When applying this bias voltage, if the normal position of the transfer drum 36 is when the gripper 176 is located below the photoreceptor drum 10, the first two rotations or one rotation are the paper feeding cycle, and the bias voltage is applied during the next copy cycle. A voltage is applied to rotate the transfer drum 36 in synchronization with the printing portion of the photoreceptor drum 10. According to such a configuration, effects similar to those of the above modification can be obtained. Note that by using an amorphous silicon film as the thin film, the transfer efficiency can be greatly improved.

It also has high mechanical strength and is hard to scratch. Furthermore, if excessive charging occurs, the charge can be easily removed using light.

[Effects of the Invention] As explained above, according to the present invention, at least the leading edge and trailing edge of the transfer paper can be fixed to the transfer drum to eliminate waving of the transfer paper, so the entire transfer paper can be fixed to the transfer drum. It can be fixed reliably and has excellent effects such as stable transfer.

[Brief explanation of the drawing]

1 to 12 show an embodiment of the present invention, in which FIG. 1 is a schematic diagram showing a fixing mechanism, FIG. 2 is a diagram showing a gripper of the tip fixing mechanism, FIG. Fig. 4 is an explanatory diagram showing the operation of the gripper, Fig. 5 is a front view showing the positional relationship between the gripper and the magnet, Fig. 6 is a perspective view showing the configuration of the magnetic attachment part, and Fig. 7 is the control mechanism of the gripper. 8th plan view showing
9 is a front view showing the gripper control mechanism, FIG. 9 is a plan view showing the pin control mechanism, FIG. 10 is a front view showing the pin control mechanism, and FIG. 11 is an external perspective view of the color printer. FIG. 12 is a diagram schematically showing the internal configuration of the printer, FIG. 13 is a diagram showing the first modification, and FIG.
The figure shows a second modification, and FIG. 15 shows a third modification. p...Transfer paper, 36...Transfer drum, 10...Image carrier (photosensitive drum), 22...Transfer device, 48...
... Fixing means (fixing mechanism), 50... Tip fixing means (
Tip fixing mechanism), 52... Rear end fixing means (rear end fixing mechanism), 60a... Presser piece, 60... Magnet, 62...
- First magnetically attached part, 64... Second magnetically attached part, 66...
First separating means (first separating mechanism), 76... Second separating means (second separating mechanism), 172a...
Conductive rubber roller, 174...voltage application means (power supply)
, 184... Corona charger, 192... Thin film,
194...Corona charger. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 II Figure 4 Figure 5 Figure 6 Figure 11 Figure 13

Claims (13)

[Claims] (1) In a transfer device that wraps a transfer paper around the circumferential surface of a transfer drum and transfers an image carried by an image carrier onto the transfer paper, at least a leading edge and a trailing edge of the transfer paper are respectively attached to the circumferential surface of the transfer drum. A transfer device characterized in that the transfer drum is provided with a fixing means for fixing it to the transfer drum. (2) The transfer according to claim 1, wherein the fixing means includes a leading edge fixing means for fixing the leading edge of the transfer paper and a trailing edge fixing means for fixing the trailing edge of the transfer paper. Device. (3) The rear end fixing means is characterized in that a magnet having a presser piece is magnetically attached to the transfer drum, and the rear end of the transfer sheet is pressed against the transfer drum by the presser piece. Transfer device described in Section 1. (4) The trailing edge fixing means is provided with a magnet having a presser piece that presses the rear end of the transfer paper against the transfer drum, and the transfer drum, and is arranged so that the transfer paper is pressed against the transfer drum with the presser piece. a first magnetically attached portion that magnetically attaches the magnet; a second magnetically attached portion that is provided outside the transfer drum that magnetically attaches the magnet; and a second magnetically attached portion that magnetically attaches the magnet to the first magnetically attached portion. a first separating means for separating the magnet from the first magnetically attached part and magnetically attaching it to the second magnetically attached part; 3. The transfer device according to claim 2, further comprising a second separating means for separating from the magnetically attached portion and magnetically attaching it to the first magnetically attached portion. (5) The fixing means includes charging means for pre-charging the transfer paper to be wound around the transfer drum and fixing the transfer paper to the transfer drum using electrostatic force. transcription device. (6) The charging means includes a conductive rubber roller that rolls into contact with the transfer paper, and a voltage application means that applies a voltage to the conductive rubber roller.
Transfer device described in Section 1. (7) The transfer device according to claim 5, wherein the charging means includes a bristle brush roller that rolls into contact with the transfer paper, and a voltage application means that applies a voltage to the bristle brush roller. . (8) The transfer device according to claim 5, wherein the charging means includes a corona charger that charges the transfer paper. (9) The fixing means is characterized by comprising an insulating thin film polymerized on the peripheral surface of the transfer drum, and charging means for charging this thin film and electrostatically attracting the transfer paper. A transfer device according to claim 1. (10) In the transfer step of rotating the transfer drum a plurality of times to transfer images in a superimposed manner onto the transfer paper, the charging means charges the transfer drum during the first rotation, and charges the transfer drum during the second rotation.
10. The transfer device according to claim 9, wherein charging is not performed after the rotation. (11) The transfer device according to claim 9, wherein the fixing means includes voltage applying means for applying a bias voltage to the transfer drum. (12) The transfer device according to claim 9, wherein the insulating thin film is made of a photoconductive material. (13) The transfer device according to claim 12, wherein the photoconductive substance is amorphous silicon.