JPH0952349A - Image transfer apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unevenness in gripping and to prevent longitudinal wrinkling arising from the unevenness of gripping by a method wherein a downwardly-warped elastic holding plate is provided at each of grippers of a plurality of holding clamps, each composed of a gripper for being hooked to a transfer cylinder and a gripper seat, for holding the upper side of an image receptor, and the size of the gripper seat is made at least the same as that of the holding plate. SOLUTION: A plurality of holding clamps, each composed of a gripper 3 and a gripper seat 4, for holding the upper side of an image receptor 22 are provided, together with a holding clamp for holding the under side of the image receptor 22, at a partly-cut-out part formed at the surface of a transfer cylinder. A downwardly-warped elastic body 23 is provided at the underside of the gripper 3, and the size of the gripper seat 4 is made at least equivalent to that of the elastic body 23. The elastic body 23 is desirably made from an aluminum plate, and the image receptor 22 is caught between the elastic bodies 23 and the gripper seats 4. Each of gaps in the axial direction of the transfer cylinder between each of the gripper seats 4 is slightly narrower than each of gaps between each of the elastic bodies. The image receptor 22 is held with the elastic bodies 23 and the gripper seats 4, and because of relatively narrow distance between each of the elastic bodies 23, the image receptor 22 is held flat.

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 provided with a clamp for gripping an upper side of an image receptor, which is excellent in gripping property of the image receptor which is easily curled by heat. More specifically, the present invention relates to an image transfer device provided with a clamp for gripping an upper side of an image receptor having excellent workability.

[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, or 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 having an image forming material attached thereto and a transfer cylinder having an image receiving member attached thereto are arranged so that the photosensitive layer of the image forming material and the image receiving member face each other. An apparatus has been generally proposed in which both cylinders are contact-pressed with each other to transfer the image formed on the photosensitive layer to an image receptor at a nip between the cylinders. To produce multicolored prints or prepress proofs, color originals are color separated to form imagewise exposed image-forming materials of each color, for example yellow, magenta, cyan and black, which are then sequentially formed. The image formed on the photosensitive layer of the material will be transferred to the image receptor.

Therefore, when a multicolor prepress proof or the like is produced, several image forming materials are used for the same image receptor. Therefore, in order to facilitate the attachment / detachment operation of the image receptor and the image forming material,
The applicant of the present application has proposed an image transfer device in which an image receptor or a tray for placing an image forming material is provided on the impression cylinder side or the transfer cylinder side, which is freely tiltable (Japanese Patent Application No. 3-206516, Japanese Patent Application No. 3-206516). 206517). As a result of further studies, it was found that when the image receptor such as paper is thin, there is a problem that curling easily occurs due to heat and hot air on the surface of the transfer cylinder. When curl occurs, uneven gripping by the nail occurs. When the image receptor in such a state is wound around the transfer cylinder, vertical wrinkles occur and a clear transferred image cannot be obtained.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to an image transfer apparatus capable of preventing uneven gripping that occurs when a thin image receptor is gripped by a clamp for gripping the upper side of the image receptor and vertical wrinkles caused thereby. For the purpose of providing.

[0006]

SUMMARY OF THE INVENTION The present invention comprises an impression cylinder having an image forming material attached thereto and a transfer cylinder having an image receptor attached thereto, and the image forming material and the image receiving body are rotated by rotating the impression cylinder and the transfer cylinder. In a device for introducing an image into a nip between an impression cylinder and a transfer cylinder to transfer an image formed on a photosensitive layer of the forming material to an image receptor, the transfer cylinder includes a plurality of nails and a nail seat. The image receptor upper side gripping clamp and a plurality of image receptor lower side gripping clamps, the image receptor upper side gripping clamp, the claw is provided with a pressing plate made of an elastic body curved downward, Provided is an image transfer device characterized in that a nail seat has at least an area corresponding to the area of a pressing plate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. 1 shows a schematic sectional view of an image transfer device suitable for use in the present invention, and FIG. 2 shows a schematic sectional view of a tray according to the present invention.

The structure of the image transfer device used in the present invention will be described below with reference to FIG. A plurality of image receiving member upper side (holding side) gripping clamps including a nail 3 and a nail seat 4 and a plurality of nails 5 and a nail seat 6 on a partially cutout portion 2 provided on the surface of the transfer cylinder 1. An individual image receptor lower side (holding side) gripping clamp is provided. Nail seat 4, 6
Are installed at intervals in the axial direction of the transfer cylinder.
This is to prevent the nail seat from bending due to the heat of the transfer cylinder. An ironing roll 9 and a pressing bar 10 which are movable in the radial direction of the transfer cylinder are provided near the surface of the transfer cylinder. An inclined portion may be provided in the vicinity of the cutout portion of the transfer cylinder, and the nail seat 4 may be installed on the inclined portion so that the image receptor is held between the inclined portion and the nail 3. The partial cutout portion 12 provided on the surface of the impression cylinder 11 has a fixing member 14 for the blanket 13.
Is provided. An inclined portion 15 is provided between the partial cutout portion and the surface of the impression cylinder, and a pin bar 16 is installed on the inclined portion. Double-sided adhesive tape 17 on the surface of the impression cylinder near the slope
Is provided. An ironing roll 18 that is movable in the radial direction of the impression cylinder is provided near the surface of the impression cylinder.
Above the intermediate portion between the transfer cylinder 1 and the impression cylinder 11, there is provided a tray 20 which is tiltable around the shaft 19 toward the transfer cylinder side and the impression cylinder side.

After the image receptor (not shown) is placed on the tray 20, the tray is tilted to the transfer cylinder side, and the image receptor is held by the claw 3 and the claw seat 4. Then, the transfer cylinder is rotated in the direction of the arrow in the figure, and the lower side of the image receptor is held by the nail 5 and the nail seat 6. During rotation, the image receptor is brought into close contact with the surface of the transfer cylinder by the ironing roll 9. The pressing bar 9 is freely movable into the cutout 8 between the gripper clamp and the impression cylinder surface, and assists in the discharging operation of the image receptor. After the image forming material (not shown) is placed on the tray 20, the tray is tilted to the impression cylinder side, and the hole provided on the upper side of the image forming material is inserted into the pin of the pin bar. Then, the impression cylinder is rotated in the direction of the arrow in the figure, and the upper side and the lower side of the image forming material are fixed with the adhesive tape 17. While the impression cylinder is rotating, the image forming material is brought into close contact with the impression cylinder surface by the ironing roll 18. After applying the image receptor and the image-forming material to the transfer cylinder and the impression cylinder, the protective film is peeled off from the image-forming material so that the photosensitive layer of the image-forming material and the image-receiving element face each other, and It is introduced into the nip and the image formed on the photosensitive layer is transferred to the image receptor.

According to the present invention, in the image transfer apparatus having the above-mentioned structure, the nail 3 is provided with an elastic body curved downward, and the nail seat 4 is provided.
Is provided with an area corresponding to at least the area of the elastic body. The elastic body is curved downward with the circumferential direction of the transfer cylinder as the axial direction. As the elastic body, a metal plate having a thickness of about 0.1 to 0.5 mm, for example, an aluminum plate is preferably used. According to the present invention, a downwardly curved elastic body is installed on the nail 3, and the image receptor is held between the elastic body and the nail seat. The size of the elastic body is set so that the gap between the elastic bodies is about 5 to 20 mm, preferably about 5 to 15 mm in the longitudinal direction of the transfer drum axis. The length of the elastic body in the longitudinal direction of the transfer cylinder axis is 50 to 9
0 mm, preferably about 60-80 mm,
It is preferable because a thin image receptor can be gripped without curling. The length of the elastic body in the circumferential direction of the transfer cylinder is
It is about 10 to 30 mm, preferably about 10 to 20 mm. The clearance of the nail seat 4 in the axial direction of the transfer cylinder is set to be slightly narrower than the clearance between the elastic bodies. If the surface of the nail seat on the side sandwiching the image receptor is made smooth, the image receptor slides well, and insertion errors when inserting the clamp can be prevented.

FIG. 2 is a drawing explaining a state in which the image receptor is clamped by the image receptor gripping side of the present invention. FIG. 2 shows a state in which the nail 3 is opened and the image receptor is inserted between the nail 3 and the nail seat 4. When the image receiver, for example, the paper 22 is thin, the paper is curled due to the heat generated by the transfer cylinder. 2 shows a state after the paper is gripped by the claw 3 and the claw seat 4. The paper 22 is gripped by the elastic body 23 and the claw seat 4, the distance between the elastic bodies 23 is relatively short, and the paper 22 is flat. FIG. 3 shows a state in which the paper 22 is gripped by the claw 3 and the claw seat 4. The distance between the claws 3 is wide, and unevenness is recognized on the paper between the claws 3. It was confirmed that this unevenness increases even after gripping because it is affected by heat. When the paper in such a state is attached to the transfer cylinder while being brought into close contact with the transfer cylinder surface by the ironing roll 9, vertical wrinkles are generated, and a good transferred image cannot be expected to be obtained.

[0012]

According to the present invention, there is provided an image transfer device provided with a transfer drum which can be attached to the transfer drum without wrinkles even when the image receptor is thin. According to the present invention, there is provided an image transfer device which does not cause defective image transfer due to wrinkles of an image receptor.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a gripper side clamp of the present invention and a usage state thereof.

FIG. 3 is an explanatory view showing a usage situation by a conventional gripping side clamp.

[Explanation of symbols]

 1 transfer cylinder 3 gripper side claw 4 gripper side claw seat 11 impression cylinder 23 elastic body

Claims (1)

[Claims] 1. An impression cylinder having an image forming material attached thereto and a transfer cylinder having an image receptor attached thereto, wherein the image forming material and the image receiving body are rotated by the rotation of the impression cylinder and the image receiving body. In an apparatus for transferring an image formed on a photosensitive layer of the forming material to an image receptor by being introduced into a nip between them, a transfer cylinder is provided for gripping a plurality of image receptor upper sides of a nail and a nail seat. A clamp and a plurality of image receptor lower side gripping clamps are provided, and the image receptor upper side gripping clamp is provided with a pressing plate made of an elastic body curved downward on the claw, and the claw seat is at least the pressing plate area. An image transfer device having an area equivalent to.