JPS5950460A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To convey a transfer material with good accuracy and to improve registration, by disposing electrostatic chargers for transfer and electrostatic chargers for sepn. to supports which support a transfer material between the spacing positions of the respective image carrying bodies which are made shorter than the length of the transfer material. CONSTITUTION:Respective photosensitive drums 1 are disposed at the space between each other shorter than the length in the moving direction of a transfer material P, and supports 21, 22, 23 which support the material P are formed to have smooth surfaces. While the material P fed to the drum 1a is attracted by the drum 1a, an image is transferred thereon with an electrostatic charger 5a for transfer, and the attraction force thereof is weakened by an electrostatic charger 12a for sepn., thus the transfer material is separated over the entire part in the transverse direction and since the resistance on the surfaces of the supports is small, the material is conveyed straightforward along the rotating direction of the drum 1a. The transfer material P across the two drums receives the conveying forces by the two drums. The transfer material is therefore conveyed, transferred and separated successively and is positively conveyed; therefore, the transfer material is obtd. with good registration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention develops latent images formed on a plurality of image carriers by electrophotography or electrostatic recording, and sequentially superimposes the resulting visible images on a sheet of transfer paper. The present invention relates to a multicolor image forming apparatus that transfers and forms multicolor images.

-1 In the apparatus for obtaining multicolor images such as color images as described above, one of the major problems is the registration of overlapping transfers, which determines the quality of the images. yellow, macenta,
When a color image is formed by superimposing the three primary colors of cyan and a blank, the registration] ration is Q. 2mm
It is desirable to keep it within a certain range. Therefore, in this type of equipment, it is necessary to convey the transfer material straight.

On the other hand, since the transfer material is electrostatically attracted to the image carrier during transfer, it is necessary to remove the lever adhesion and separate the transfer material from the image carrier and convey it.

Conventionally, as shown in Fig. 1, there is a method in which a gripper 7 holds the leading edge of the transfer paper in its mouth and pulls it, and repeats the process of transporting, transferring, and flashing, or the method of using a mensch as disclosed in Japanese Patent Application Laid-Open No. 129045/1983. A method is used to transport the transfer material by adsorbing it to a heel.

The former is as follows.

This multicolor image forming apparatus has four photosensitive drums (laelb), which are image carriers, in order to form images in each color of yellow, macenta, cyan, and black and transfer them onto a transfer material in an overlapping manner.
ΦICψld (Hereinafter, each device that is immersed in each soul 1, Rano, does not hear the symbols a-b-c-d that are phantom 1.)
is placed. Below these photosensitive drums 1, a pair of chains 8 are strung around sprockets 1, 9, and 9, and a gripper 7 is attached to the chain 8. When sprockets 1, 9, and 9 rotate, the chain. The printer 8 moves to pull the printer 7. In the multicolor image forming apparatus having this structure, the transfer material P fed from the paper feed section (not shown) is gripped at the leading end by the gripper 7,
It moves together with the gripper 7. and photosensitivity}・Lamb 1a
・1bΦIC-ld'' 1 color image is superimposed one after another by transfer chargers 5a, 5b, 5C, 5d and transferred to transfer material P.
transferred onto the . Next, the transfer sheet P is released from the grip of the gripper 7 and is sent to the fixing device 10.

In the above example, the nail roll with good registration
In order to make the grip as difficult as possible, move the gripper 7 by J'1.
It is necessary to completely synchronize the rotation of the photosensitive drum 1a, fist 1b, and ICΦ1d to eliminate fluctuations. Therefore, the precision of the drive control, sprockets 1, 9, 9, chain 8, etc., is extremely high and manufacturing is difficult.

Further, the drive and opening/closing mechanism of the presser 7 is large and complicated. In the case of continuous copying, it is necessary to arrange a large number of grippers 7 on the chain 8, resulting in a dog-shaped apparatus and high cost.

Furthermore, the transfer chargers 5a and 5b correspond to the thickness of the grimper 7.
- Connect the corona discharge openings of 5C and 5d to the photosensitive drums la and 1.
It is necessary to keep it away from the IC and 1d, which increases the spread of the transferred corona, causing the image to scatter and deteriorate the tracing quality.

The latter method, in which the belt is electrically charged and the transfer material is attracted and conveyed, requires a device for cleaning the belt support from dirt with 1-toner in the transfer section. In addition, high precision is required for driving the belt support, as in the former case. Therefore, it is no different from Maenagashi in that it will become a large, high-cost city.

The present invention has been made in order to solve the second problem of the conventional technology mentioned above.It reliably separates the transfer material from the photosensitive drum and conveys it with high precision, and overlaps the transfer material with good registration and ratio. A low-cost multi-color image forming device that has made it possible to achieve this goal!・There are things that can be done.

In order to achieve the above object, the multicolor image forming apparatus according to the present invention includes a plurality of image carriers 1a, 1b, IC, and 1d, latent image forming means provided on each of the image carriers, and a transfer η. In a multicolor image forming apparatus which includes a transfer means, a transfer material separation means, and a cleaning means, and sequentially transfers each visible image on the image carrier to the transfer sheet, the transfer means is used as a transfer means. Banding device 5a, 5b, 5c, 5d and separation 1 as transfer material separation means; Electric appliance 12a◆12b-L2cφ12
d, and each image JL! It is characterized in that the spacing between the bodies is changed to 10 times less than the length of the material P, and supports 21, 22, 23 are fixed at the intermediate position 1H of each image carrier to support the transfer material P. There is.

Examples of the present invention will now be described in detail with reference to the description on page 4.

The 21st Δ is a multicolor image forming apparatus to which the present invention is applied.

1a, 1b, lc, and 1d are 1.5♀ light toners for forming images in each color of yellow, black, cyan, and black. 2a, 2b, 2C, 2d1±primary charger, 3a, 3b ● 3C ● 3d optical information source such as laser beam, 4a, 4b, 4C, 4d are developer, 5a, 5b, 5
c 5d is the transcription I 1″f′ tonne, 12a, 12b, 12
c・12d Hobun*Jll 4↑;；Electrical appliances, 6a・6b・
6cΦ6d has a cleaner.

The mutual spacing 1i of the photosensitive trams 1a, 1b, 1c, and 1d is shorter than the length of the transfer material P. Between these photosensitive drums are support guides 21 and 2 that support the transfer material.
2●23 will be fixed. One surface of each of the support guides 21, 22, and 23 is located approximately on the same level as or slightly below the surface formed by the lower side of each photosensitive drum. Support guy l・21・22・2
3. On the abutting surface of the transfer material P, a material and shape with low contact resistance, such as brass tink or metal, are formed into ribs 26 that run downward in the conveyance direction of the transfer material, and the surface thereof is made smooth (see FIG. 4).

In addition, a feeding kite 24 is arranged on the side of the lees feeding roller IJ of the photosensitive tram 1a, and a discharge guide 25 is arranged on the side of the fixing device 10 of the photosensitive drum 1d.

In such a multicolor image forming apparatus, when the transfer material P is sent from the transport roller 11 to the photosensitive drum 1a by sliding on the transport guide 24, corona discharge is applied by the transfer charger 5a. It will be done. The transfer material P is 1.
Transfer is performed while being attracted to and being pulled by.

Immediately after the transfer, the transfer plate P is charged with an AC corona discharge 1 [t or a corona discharge with a polarity opposite to that of the transfer corona is applied from the back side of the photosensitive drum J by the charger 12a to weaken the suction force. a
From 6 zo 1 minute.

The transfer material P is given a certain amount of conveying force by the photosensitive drum la during adsorption during transfer. In addition, the transfer material P is charged N1 in the entire width direction (direction perpendicular to the feed direction) by rigid charging, and the conveyance resistance is reduced, so that the rotation nozzle of the photosensitive drum 1a is
It is conveyed straight along the direction.

Subsequently, the transfer material P is conveyed to the photosensitive drum lb while sliding on the support guide 21. In this case, the distance between the photosensitive drum 1a and the photosensitive drum 1b is jl (1) longer than the length of the transfer material P, so that while the photosensitive drum 1a is transporting, the photosensitive drum 1b is also transporting.

In this way, the transfer material is transported, transferred, and separated one after another.
The second image becomes a multicolor image and is transported to the fixing device 10,
When the purification is completed, it will be discharged.

The obtained multicolor image has good C distortion.

Next, the results of experiments conducted using the apparatus of the above embodiment will be described.

(Experiment 1) The device has photosensitive drums 1a, 2b, 2C, and 2d with a diameter of 60 mm, the spacing between the photosensitive trams 1a, 1b, 1c, and 1d is 160 mm, and the developing units 4a, 4b, 4C, and 4d are compact 1-component two-component developing devices. It is a vessel. As the transfer material, A4 size transfer paper from NP Color Copier was used as the transfer material. Transfer corona applied voltage is +6. O
K V, sub-corona applied voltage is A C 4. OK I made it to V. As a result, sufficient overlapping transfer and stable flJL conveyance were obtained. Although a cross line image with a vertical (feeding direction) interval of 5 mm and a width of 15 mm was formed, straight and evenly spaced images were transferred. However, the image obtained was slightly shrunken.

(Experiment 2) Under the same conditions as Experiment 1, the two ends of the transfer material P were
When I formed a cross line image by rotating it as in Experiment 1 by keeping it at 0 mm and not developing it, this time I was able to get a straight image with almost no shrinkage and evenly spaced images.

-1 The following considerations were made from the series of experimental results described in Section 2.

The shrinkage of the image in Experiment 1 is due to the amount of 1.ner deposited on the image area of the photosensitive tram 12 during development, and the amount of fogging 1.ner and a trace amount of carrier {=1. The suction force during transfer is weakened when the transfer material P is attached to the photosensitive drum, and the transfer material P is easily misaligned with the photosensitive drum because the 1.
determined.

Therefore, the 1.LJ side edge of the 11.mu photographic material P is a non-image area, and a part is formed between the transfer material P and the photosensitive ram in which no 1.na or a small amount of carrier is present. If the photosensitive drum attracts and conveys the transfer material, a good multicolor image without shrinkage will be transferred to the transfer material.

FIG. 3 is a plan view of another embodiment of the support chisel 1, 21, in which ribs 26 are provided in the shape of veins.

FIG. 4 shows another embodiment of the present invention, which ensures the conveyance force in transfer g++. Transcription/j1} Electric appliance 5 b:
By providing the MfjII with a conveying roller 14 that slides and rotates on the photosensitive 1 and ram 1 to support and convey the transfer material P, the transfer material P can be conveyed sufficiently and accurately.

The surface of the conveyance roller 14 is preferably made of a rubber-like elastic material so as not to damage the photosensitive drum 1 and to provide sufficient conveyance force to the transfer material P. t unit 5 and hibun n1・j1
:・To prevent deterioration due to corona discharge of the electric appliance 12, use ozone-sensitive rubber-like elastic material such as silicone rubber or EPDM (ethylene-propylene Φ-terpolymer).

As shown in FIG. 5, make sure that the transfer corona discharge does not hit the conveyance roller 14, and that the transfer corona discharge and spark discharge do not occur on the support of the conveyance roller 14. A two-edge cover 15 may also be provided.

The same effect can be obtained even if the conveying roller 14 is provided outside the longitudinal extension 1- of the transfer charger 5.

No. 6 1a shows another embodiment of the conveying roller l4. In the embodiment shown in FIG. 4, the portion of the conveyance roller 14 that pinches the transfer phase P is a soft elastic body 14A such as a sponge or a soft comb, and the other 1'! b is a hard elastic body such as hard rubber 1
4B, and the surfaces of the photosensitive drums 1, 1 are made of a scratch-resistant material IB, such as metal, at the portion where the hard elastic body 14B rests. Therefore, the photosensitive ram 1 will not be damaged, and the conveying roller 14 will not be tilted.

7th 1,;l! 1 indicates another embodiment. If the diameter of the photosensitive 1/ram 1 is large and the transfer paper is weak, the part 811 becomes unstable. Then, the separation of the transfer material P is ensured by interposing the leaf body as the γ of Mylar q, which is the opening of the minute N1, at the edge of the photosensitive drum 1 and the transfer paper P as It is something to do. Conveyance roller 14
A cutout hole is provided in the NI auxiliary belt 16 at a portion where the transfer charger 5 is located so that it comes into contact with the photosensitive drum 1.

FIG. 8 shows another embodiment of the conveying roller 14 in which a Nt auxiliary belt 16 as shown in FIG. 7 is arranged. The portion of the transport roller 14 that pinches the transfer paper P is made of a soft elastic material 14A such as sponge soft rubber, and the other portion is made of a hard elastic material 14B such as hard rubber.
The surface of the optical drum 1 at the contacting portion thereof is made of a scratch-resistant material IB such as metal. In this case, a notch hole is provided in each of the auxiliary separation shells 1 and 16 so that the soft elastic body 14A corresponds to the scratch resistance of the photosensitive tram 1, 81 {minute IB.

[Brief explanation of the drawing]

FIG. 1 is a normal mj diagram of a conventional multicolor image forming apparatus δ, FIG. 2 is a front view of a multicolor image forming apparatus to which the invention is applied, and FIG. Figure 4 is a perspective view showing the embodiment around the transfer charger 50, Figure 5, Figure 6,
FIG. 7 and FIG. 8 are diagrams showing another embodiment. 1a, 1b, 1c, 1d is an image carrier, 5a, 5b, 5c
s5d is transfer charger, l2a●12b@12c-12d
21-22-23 is a supporting body, and P is a transfer material. -397-

Claims (1)

[Claims] (1) A plurality of image carriers, and a latent image forming means, a transfer means, a transfer material separating means, and a cleaning means provided on each of the image carriers, and the image carriers each have a visible image. −
In a multicolor image forming apparatus that sequentially transfers images onto a sheet of transfer material, a transfer charger is used as a transfer means, and a transfer charger is used as a transfer material NF means. A multicolor image forming apparatus in which a support is fixed at an intermediate position of each image carrier to support the transfer material, with the length of the transfer material in the direction of the moving force.