JPH06270381A - Image transfer device - Google Patents

Abstract

PURPOSE:To prevent inaccuracy in register, by providing, in the case of driving and rotating one cylinder by the use of a drive means and synchronously rotating the other by the use of a gear, the synchorously rotated cylinder with a rotation-load application means. CONSTITUTION:A gear 31 is driven and rotated by a motor 33 when an image receiving body is attached to a transfer cylinder 1, and an impression cylinder 8 is driven and rotated by the motor when an image formation material is attached to the impression cylinder 8; both the cases, a gear 30 and the impression cylinder are disconnected by a clutch. To transfer an image from the image formation material to the image receiving body, the gear 30 and the impression cylinder 8 are connected, the transfer cylinder 1 is driven by the motor 33, notches 2 and 9 face each other to rotate synchronously the transfer cylinder 1 and the impression cylider 8, both of which have not been in contact with each other. Then, the surfaces of both the cylinders come into contact with each other to make a nip, and the image is transferred. At this time, a load in the direction of the rotation is applied to the impression cylinder 8 by the action of a brake 35 and the rotation is transmitted without creating a gap between the teeth of the gears 30 and 31. Therefore, the fixed positional-relationship between both the cylinders is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transfer device. More specifically, the present invention relates to a beautiful multicolor prepress proof with excellent registration accuracy, and an image transfer apparatus including an impression cylinder and a transfer cylinder for obtaining multicolor printed matter.

[0002]

2. Description of the Related Art Recently, an image-forming material having a photosensitive layer coated on one surface of a support is imagewise exposed, and then the image formed on the photosensitive layer is heated, generally at about 100 ° C., BACKGROUND ART Single-color or multi-color prepress proofs suitable for proof printing to be transferred to an image receptor such as paper have come to be produced. The image forming material comprises a support, a photosensitive layer formed on one surface of the support, and a protective film. As the support and the protective film, a thin film or sheet made of a material such as cellulose acetate, polystyrene, polyvinyl chloride, polyethylene terephthalate is used. As the image receptor, an appropriately selected printing material such as paper or film is adopted.

As an apparatus for producing the above-mentioned prepress proof, an impression cylinder to which an image forming material is attached and a transfer cylinder to which an image receptor is attached, and a photosensitive layer of the image forming material are opposed to a gift receptor. Generally, a technique has been proposed in which both cylinders are contact-pressed to transfer the image formed on the photosensitive layer to an image receptor at the nip between the cylinders. To produce multicolored prints or prepress proofs, color originals are color separated to produce imagewise exposed image-forming materials of each color, for example yellow, magenta, cyan, and black, and then these images in sequence. The image formed on the photosensitive layer of the forming material will be transferred to the image receptor.

As an attachment device for the image forming material in the impression cylinder, a pin bar has been usually used in order to facilitate the registration of each color. The pin bar has a plurality of pins installed on a plate extending in the axial direction of the impression cylinder. However, even if the pin bar was installed, the registration accuracy was not sufficient by itself.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multicolor prepress proof and a multicolor printed matter, which is an image transfer device which is sufficiently satisfactory in registration accuracy.

[0006]

According to the present invention, there are provided an impression cylinder having an image forming material attached thereto and having a notch on the surface thereof, and a transfer cylinder having an image receptor attached thereto and having a notch on the surface thereof. The image forming material and the image receiving member are provided with the driving means for respectively driving the impression cylinder and the transfer cylinder and the gear capable of synchronously rotating both cylinders. In an image transfer device that transfers the image formed on the photosensitive layer of the image-forming material to the image receptor by being introduced into the nip between them, one cylinder is driven and rotated by the driving means, and the other cylinder is rotated by the gear. There is provided an image transfer device characterized in that a rotation load imparting means is provided on a cylinder on the side that is synchronously rotated during synchronous rotation.

The present invention further provides an image transfer apparatus characterized in that the transfer cylinder is driven by the driving means, the impression cylinder is synchronously rotated by the gear, and the impression cylinder is provided with a rotational load applying means.

The present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a schematic sectional view of an image forming apparatus including an impression cylinder to which an image forming material suitable for use in the present invention is attached and a transfer cylinder to which an image receptor is attached.

The structure of the transfer cylinder 1 will be described with reference to FIG. A partial cutout 2 is provided on the surface of the transfer cylinder 1, and a clamp including a nail 3 and a nail seat 4 which are upper side (holding side) attachment means of the image receptor is provided in the partial cutout, and a lower side ( Mouth side) Claw 5 and claw seat 6 as attachment means
Install a clamp consisting of. The image receptor (not shown) such as paper is attached by grasping the upper side by the clamp on the gripper side, rotating the transfer cylinder 1 in the direction of the arrow to wind the image receptor around the transfer cylinder 1, and then clamping on the gripper side. By holding the lower side of the image receptor.

The structure of the impression cylinder 8 will be described with reference to FIG. The impression cylinder 8 is partially provided with a notch 9, and the blanket 10 wound around the surface of the impression cylinder 8 is fixed by the blanket fixing means 11 in the notch. An inclined portion 12 is provided between the partial cutout portion 9 and the impression cylinder surface (circumferential surface), and the pin bar 13 is installed on the inclined portion. Installation of the pin bar 13
It is carried out by pressing the pin bar against the surface of the impression cylinder with a blanket having holes at positions corresponding to the pins of the pin bar. The height of the tip of the pin bar 13 is not outside the circumferential surface of the impression cylinder 8. This is because the surface of the pin bar 13 or the transfer cylinder 1 is not damaged when the impression cylinder 8 and the transfer cylinder 1 rotate. Adhesive tape 15 is provided on the surface of the impression cylinder near the inclined portion 12 on which the pin bar 13 is provided on the impression cylinder surface and in the vicinity of another inclined portion of the partially cutout portion 9. For attachment of the image forming material (not shown), holes corresponding to the pin bars 13 are provided on the upper side of the image forming material. After inserting these holes into the pins of the pin bar 13, the impression cylinder 8 is rotated to wind the image forming material around the impression cylinder 8, and the upper and lower sides of the image forming material are fixed to the impression cylinder surface with the adhesive tape 15. .

FIG. 2 shows an example of printing pressure adjusting means for the transfer cylinder 1 and the impression cylinder 8. The impression cylinder 8 and the transfer cylinder 1 include a rotary shaft 20,
It is supported by the side frame 21 by 20 '. The printing pressure adjusting means 22 is provided on both end surfaces of the transfer cylinder 1 in this embodiment. The slide block 23 for adjusting the magnitude of the printing pressure is provided on the side frames on both end surfaces of the impression cylinder or the transfer cylinder in order to make the printing pressure uniform in the axial direction. The slide block 23 is provided with moving means for moving the slide block in the transfer cylinder direction so that the printing pressure generated by the impression cylinder and the transfer cylinder is constant. The moving means includes a spring bearing 24 installed on the slide block 23, a coil spring (elastic member) 25 for pressing the spring bearing toward the slide block, and an adjusting bolt 26 for appropriately adjusting the elastic force of the coil spring. It comprises an adjustment bolt receiver 27 for fixing one end of the moving means to the side frame. Although the coil spring is used for adjusting the printing pressure by the moving means in the above description, the invention is not limited to the coil spring, and another elastic member such as a leaf spring or a leaf spring may be used. The elastic member is not limited to the elastic member, and hydraulic pressure, pneumatic pressure, or the like may be used. The impression cylinder or the transfer cylinder is always pressed against the transfer cylinder or the impression cylinder side by the printing pressure adjusting means.

According to the present invention, in the above-mentioned image transfer apparatus, there is provided a rotational load applying means for applying a rotational load to the latter cylinder when one cylinder is driven by the driving means and the other cylinder is synchronously rotated by the gear. The feature is that it is provided.

The operation of the present invention will be described below. Figure 3
FIG. 3 is an explanatory diagram showing an example of a drive mechanism of an image forming apparatus suitable for use in the present invention. The gears 30 and 31 have the same rotation axis center as the transfer cylinder 8 and the transfer cylinder 1, respectively, and the pitch circle diameter is the same as the diameter of the impression cylinder and the transfer cylinder.
Gears 30 and 31 always mesh. A brake 35 serving as a rotational load applying means is provided on the rotary shaft of the impression cylinder 8. Gear 30
A clutch (not shown) is provided between the pressure drum 8 and the pressure drum 8 so that the drive connection for synchronously rotating the pressure drum 8 and the transfer drum 1 can be disconnected. When the image receptor is attached to the transfer cylinder 1, the gear 31 is driven and rotated by the motor 33. At this time, the coupling between the gear 30 and the impression cylinder 8 is cut off by a clutch so that the rotation of the transfer cylinder 1 can be independently rotated without being transmitted to the impression cylinder 8. When the image forming material is attached to the impression cylinder 8, the impression cylinder 8 is driven and rotated by the motor 32. Also at this time, the coupling between the gear 30 and the impression cylinder 8 is disconnected by the clutch so that only the impression cylinder 8 can rotate independently without the transfer cylinder 1 rotating synchronously.

When the image is transferred from the image forming material to the image receptor, the transfer cylinder 1 is driven by the motor 33 while the connection between the gear 30 and the impression cylinder 8 is connected, and the notches 2 and 9 are formed. In a state where the transfer cylinder 1 and the impression cylinder 8 are not in contact with each other, both cylinders are rotated synchronously, and then the surfaces of both cylinders contact each other to form a nip so that image transfer is performed. At this time, a load is applied to the impression cylinder 8 in the direction of rotation by the action of the brake 35, and the rotation is transmitted without generating a gap between the tooth surfaces of the gears 30 and 31 that should contact each other.
Even when the notches 2 and 9 are rotating relative to each other before the surfaces of both cylinders are in contact with each other, the phase relationship between both cylinders is kept constant. When the brake 35 is not provided, in a state where the cutouts 2 and 9 are rotating relative to each other, the impression cylinder 8 rotates excessively due to inertia or the like, and the contact between the tooth surfaces of the gears 30 and 31 is unstable. However, if the surfaces of both cylinders contact each other and transfer is started, the transfer position becomes unstable, and the registration accuracy during multicolor transfer is significantly impaired.

The position of the clutch of the impression cylinder is not limited to the position between the gear 33 and the transfer cylinder 8 shown in this embodiment, and the transfer cylinder and the impression cylinder can be independently rotated as required. Anything can be used as long as it can disconnect the connection. Further, in the present embodiment, an example in which the transfer cylinder 1 is driven by the motor 33 that is the driving means and the impression cylinder is rotated synchronously via the gears 30 and 31 has been shown, but the driving means and the driven side The selection of the body on the side that rotates in synchronization with the body,
It is not limited to this. When the impression cylinder is driven by a motor and the transfer cylinder is rotated synchronously by a gear, a rotational load applying means is provided on the transfer cylinder.

[0016]

According to the present invention, there is provided an image transfer device capable of preventing the occurrence of defective registration accuracy and obtaining beautiful multicolor prepress proofs and multicolor printed matter.

[0017]

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an image transfer device.

FIG. 2 is a schematic explanatory diagram of a printing pressure adjusting unit.

FIG. 3 is a schematic explanatory view of a body drive mechanism.

[Explanation of symbols]

 1 Transfer Cylinder 2 Transfer Cutter Cutout Part 3 Upper Side Holding Claw 4 Claw Seat 5 Lower Side Holding Claw 6 Claw Seat 8 Impressor 9 Impressor Cutout Notch 10 Blanket 11 Blanket Fixing Device 12 Inclined Part 13 Pin Bar 15 Adhesive Tape 20, 20 ' Rotating shaft 22 Printing pressure adjusting means 23 Slide block 24 Spring bearing 25 Coil spring 26 Adjustment bolt 27 Adjustment bolt bearing 30 Gear 31 Gear 33 Gear transfer cylinder drive motor 35 Brake

Claims (2)

[Claims] 1. An impression cylinder and a transfer cylinder comprising: an impression cylinder having a cutout formed on the surface thereof, to which an image forming material is attached; and a transfer cylinder having a cutout provided to the surface, to which an image receptor is attached. And a gear that can rotate both cylinders in synchronism with each other, and the image forming material and the image receptor are introduced into the nip between the impression cylinder and the transfer cylinder by the rotation of the impression cylinder and the transfer cylinder. In an image transfer device for transferring an image formed on a photosensitive layer of a forming material to an image receptor, synchronous rotation occurs when one cylinder is driven and rotated by a driving means and the other cylinder is synchronously rotated by a gear. An image transfer device, characterized in that a rotating load applying means is provided on the body on the side where the image is transferred. 2. The image transfer device according to claim 1, wherein the transfer cylinder is driven by the driving means, the impression cylinder is rotated synchronously via the gear, and the impression cylinder is provided with a rotational load applying means.