JPS5810749B2 - Development gap forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing gap forming device in a wet electrophotographic developing device.

A part of the circumferential surface of the developing roller is immersed in the developer and while rotating, the object to be developed is fed onto the circumferential surface, and the object to be developed is immersed in the developer adhering to the circumferential surface of the developing roller. A wet-type electrophotographic developing device that performs development by bringing the surface of the object to be developed into contact with the object is effectively used when the object to be developed is relatively hard, such as a card.

In this type of apparatus, in order to prevent image flow or density unevenness and to provide a sufficient counterpolar effect to the developing roller, there is a gap between the developing roller circumferential surface and the developing surface of the developing object. , a development gap of an appropriate length is provided.

As a means for forming this development gap, for example, the one shown in FIG. 1 has been conventionally employed.

That is, in FIG. 1, the object to be developed 101 is Kanayama L1.
An electrostatic latent image is formed in the area to be developed within a length L2, and the image is fed onto the developing roller 102 with the electrostatic latent image surface, that is, the surface to be developed, facing downward.

Note that the feeding direction of the object to be developed 101 is perpendicular to the paper surface in FIG. 1.

The developing roller 102 rotates with a part of its circumferential surface immersed in the developer 103 and supplies the developer attached to the circumferential surface to the surface to be developed of the object to be developed 101 .

On both sides of the developing roller 102, there is a gap L between the end faces.
Flanges 102a and 102b are provided, and the length L2 of the developing surface of the developing object 101 is set to be approximately equal to the length L2 of the developing surface of the developing object 101.
A development gap d is formed between the circumferential surface of 2 and the surface to be developed of the object to be developed.

By the way, as shown above, the flange 1 is attached to the developing roller 102.
02a and 102b, the surface to be developed of the object to be developed 101 naturally comes into contact with these flanges, and the range L2 of the portion to be developed is
The developer 103 also adheres to other parts, causing stains or scratches on these parts.

This is not so much of a problem when developing a body to be developed in which parts other than the part to be developed are cut out, but in cases where parts other than the part to be developed are left uncut. is extremely defective.

Furthermore, an example in which such a guide member is provided separately from the developing roller is known, as shown in Japanese Patent Publication No. 40-400.

However, in the configuration in which the guide member is provided as shown in this publication, the guide member is present within the range of the width in the axial direction of the developing roller, so the peripheral surface of the developing roller and the surface to be developed of the object to be developed are Even if it is possible to form a developing gap between There is a drawback that areas other than the surface to be developed may become dirty or have scratches.

The present invention eliminates the drawbacks of the conventional ones by forming a developing gap between the developing surface of the developing object and the circumferential surface of the developing roller by a guide member separate from the developing roller. An object of the present invention is to provide a development gap forming device in a wet electrophotographic development device.

According to this invention, since the developing gap is formed by a guide member separate from the developing roller, the width of the developing roller can be determined to be the same width as the developing area of the object to be developed. There is no possibility that areas other than the area to be developed will be stained with the developer or have scratches, and the step of cutting off the stained areas can be omitted.

Hereinafter, the present invention will be described in detail with reference to illustrated embodiments.

In FIGS. 2, 3, and 4, the object to be developed 1 has an electrostatic latent image formed on its lower surface, that is, the surface to be developed,
The developing roller 5 is fed in the direction of arrow a by the conveying rollers 2 and 3 that are in pressure contact with each other, and is prevented from lifting up by the pressing roller 4 provided at the upper right in FIG.
sent to the top.

The object to be developed 1 may be, for example, a well-known electrophotographic photoreceptor in which a photoconductive material layer is provided on the surface to be developed, and this layer is charged and exposed to form an electrostatic latent image, or a photoreceptor on the surface to be developed is formed. A well-known electrostatic recording medium is used in which a dielectric layer is provided, and this dielectric layer is brought into close contact with the electrostatic latent image surface of another photoreceptor, etc., to form an electrostatic latent image by electrostatic latent image transfer. It will be done.

Note that various methods other than those described above can be employed as the electrostatic latent image forming method.

Furthermore, it is desirable that the object to be developed to which the present invention is applied be a relatively hard material, such as a card material that can be appropriately processed after development and made into an identification card, commuter pass, driver's license, etc. This allows the features of the present invention to be exhibited more effectively.

The developing roller 5 is made of hard conductive rubber, metal, or the like, is rotatably supported by a shaft 5a, and rotates in the direction of the arrow.

However, this direction of rotation is arbitrarily determined in terms of design.

As shown in FIG. 3, the shaft 5a is rotatably mounted on support plates 7a and 7b via bearings 5a and 6b, and is connected to a drive source via a gear 8 fixed to its right externally protruding end. (not shown), and is driven in the direction indicated by the arrow.

The developing roller 5 has a part of its circumferential surface immersed in a developing solution 10 contained in a container 9, and by its rotation,
The developer attached to the peripheral surface is supplied to the part to be developed of the object 1 to be developed.

At this time, the width L2 of the area to be developed and the width L3 of the developing roller (
(see FIG. 3) are determined to be equal to each other, as in the case of the object to be developed 101 and the developing roller 102.

The developer 10 is a well-known wet-type electrophotographic developer made by dispersing fine powder of a resin-treated pigment such as carbon black, or toner, in a high electrical resistance compatible liquid such as petroleum.

On both sides of the top of the circumferential surface of the developing roller 5, there are guide members 11 and 12 made of rollers made of metal or plastic.
are rotatably supported by mounting their respective shafts 11a, 12a on support plates 7a, 7b.

However, this guide member 11.12 does not necessarily have to be rotatable.

The guide members 11 and 12 slightly lift the advancing object 1 to create a development gap d (see FIG. 3) between the surface of the object 1 to be developed and the circumferential surface of the developing roller 5. By forming a developing gap d, it is possible to prevent the image from flowing due to the speed difference between the traveling speed of the object to be developed 1 and the rotational circumferential speed of the developing roller 5. 5 is fully utilized as a developing counter electrode.

This development gap d is approximately 0.2 to 1 m, although it depends on the speed difference between the traveling speed of the object to be developed 1 and the rotational circumferential speed of the developing roller.
It is set at about m.

The object to be developed 1 on the upper right side in FIG. 2 of the developing roller 5
A squeezing roller 13 and a pressing roller 14 that cooperate with each other are provided at the passing position of the image forming apparatus 1 to remove excess developer adhering to the developing surface of the developing object 1 that is progressing while being developed. do.

The squeezing roller 13 is made of metal or hard plastic, and is cleaned with a cleaning pad 15 such as felt.

Note that the pad 15 is fixed to a support 16 supported by appropriate means.

However, as the means for squeezing the object to be developed, any other suitable means can be adopted as appropriate.

Further to the right in FIG. 2 of the path of the object to be developed 1, there is a
A book lifting roller 17 and a presser roller 1 press against each other.
8 are disposed, and the object 1 to be developed absorbs moisture through the cooperation of both rollers.

In this embodiment, the contact portions of both rollers 17 and 18 are placed at a position slightly lower than the height of the top of the circumferential surface of the squeezing roller 13, so that the object to be developed 1 advances and reaches its tail end. When it reaches the position 1A where it is removed from the presser roller 4, its tail is raised and separated from the developing roller 5 to avoid the developer from being poured onto this tail.

However, this is an example of a roller arrangement when the rotational circumferential speed of the developing roller is faster than the advancing speed of the object to be developed 1,
Other roller arrangements are optional.

In FIG. 5, in order to form the developing gap d, both supporting plates 7a,
Guide member 19.20 consisting of a shelf supported by 7b
The object of the present invention can also be achieved in this way.

[Brief explanation of drawings]

Fig. 1 is a partial front view showing a conventional example of a developing gap forming device, Fig. 2 is a side cross-sectional view of a developing gap forming device showing an embodiment of the present invention, and Fig. 3 is the same as shown in Fig. 2. 4 is a partial perspective view of the device shown in FIG. 2, and FIG. 5 is a sectional view showing a different embodiment of the present invention. 1... object to be developed, 5... developing roller, 10... wet electrophotographic developer, 11.12... guide member consisting of rollers,
19.20... Guide member consisting of a shelf board, d... Development gap.

Claims (1)

[Claims] 1. A part of the circumferential surface of the developing roller is immersed in a developer solution, and while rotating it, the object to be developed is fed onto the circumferential surface,
In a wet type electrophotographic apparatus in which development is performed by bringing the surface of the object to be developed into contact with the developer on the peripheral surface, the length of the developing roller in the axial direction is set to be shorter than the width of the object to be developed. Having determined this, the object to be developed is guided to both sides of the top of the circumferential surface of the developing roller at a position higher than the top,
A developing gap forming device characterized in that a guide member separate from the developing roller is disposed to form a developing gap between the peripheral surface of the developing roller and the surface to be developed.