JP3173347B2 - Image transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transfer apparatus excellent in workability in which a pin bar can be easily replaced. More specifically, the present invention relates to an image transfer device capable of easily replacing a pin bar with high positional accuracy.

[0002]

2. Description of the Related Art Recently, an image-forming material having a photosensitive layer coated on one side of a support is image-exposed, and then the image formed on the photosensitive layer is heated, generally at about 100.degree. Monochromatic or multicolor prepress proofs suitable for proof printing or the like transferred to an image receptor such as paper have been produced. The image forming material includes 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 receiver, a printing material selected as appropriate, such as paper or film, is employed.

As an apparatus for producing the above-mentioned prepress proof or the like, an impression cylinder having an image forming material attached thereto and a transfer cylinder having an image receptor attached thereto are arranged such that a photosensitive layer of the image forming material and the image receptor are opposed to each other. In general, an apparatus has been proposed in which an image formed on a photosensitive layer is transferred to an image receptor in a nip between the two cylinders by contacting and pressing the cylinders. To produce a multicolor print or prepress proof, a color original is color-separated to produce image-exposed image forming materials of each color, for example, yellow, magenta, cyan and black, and then these image forming materials are sequentially formed. The image formed on the photosensitive layer of the material will be transferred to the image receptor.

For this reason, when preparing a multicolor prepress proof or the like, several image forming materials are used for the same image receptor. In order to obtain a transferred image with high register accuracy, the image forming material needs to be attached to the impression cylinder with high positional accuracy. A pin bar determines the positional accuracy of the image forming material. A blanket is wrapped around the surface of the impression cylinder. The blanket introduces the image forming material attached to the impression cylinder surface and the image receptor attached to the transfer cylinder surface into the nip formed between the impression cylinder and the transfer cylinder by rotating the impression cylinder and the transfer cylinder. When the image formed on the photosensitive layer of the image forming material is pressure-transferred to the image receiving member, it is provided to keep the elasticity in the nip within an appropriate range. Conventionally, the pin bar is fixed to the impression cylinder surface by a blanket provided with a hole corresponding to the pin of the pin bar so that the pin protrudes from the hole of the blanket. The mounting position is an inclined portion provided between the partially cutout portion provided on the impression cylinder surface and the impression cylinder surface.

[0005] However, there are many types of pin bars for pin intervals. Providing a large number of holes in the blanket in accordance with the pin bar used is not preferable because it changes the physical properties of the blanket. Even if many holes can be provided, it is necessary to rewind the blanket to fix the pin bar to the impression cylinder surface.
When wrapping the blanket around the impression cylinder surface, it is necessary to squeeze it tightly to prevent the blanket from loosening. In addition, in order to correct the slack of the blanket, it is necessary to perform a running-in operation and re-squeeze the slack so that there is no slack.
At this time, the pin bar may be distorted by the blanket. The distortion of the pin bar also causes distortion of the image forming material attached to the pin bar, which makes it difficult to transfer a good image to the image receptor. The type of pin bar may differ depending on the type of printed matter to be manufactured by the image transfer device. On this occasion,
The holes provided in the blanket differ depending on the type of printed matter and, consequently, the type of pin bar. In this case, there is a possibility that a hole cannot be formed in the blanket unless the type of printed matter is determined.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above disadvantages associated with the conventional pin bar mounting, and provides an image transfer apparatus having a pin bar that can be easily mounted with high positional accuracy.

[0007]

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 image receptor are rotated by rotating the impression cylinder and the transfer cylinder. In the nip between the impression cylinder and the transfer cylinder to transfer the image formed on the photosensitive layer of the forming material to an image receptor, wherein the impression cylinder has a partially cut surface provided on the surface of the impression cylinder. A notch portion, an inclined portion provided between the notch portion and the impression cylinder surface, a blanket wound around the impression cylinder surface, and a pin bar for determining an attachment position of the image forming material attached to the inclined portion. The pin bar is mounted on a blanket via an adhesive or a pressure-sensitive adhesive, and is covered with a sheet coated with a pressure-sensitive adhesive on one side provided with holes corresponding to the pins of the pin bar. An image transfer device is provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic sectional view of an image transfer apparatus suitable for carrying out the present invention. FIG. 2 is a schematic cross-sectional view showing an installation mode of the pin bar. Hereinafter, an outline of the image transfer apparatus will be described with reference to FIG. A partially cut-out portion 2 provided on the surface of the transfer cylinder 1 includes a claw 3 and a claw seat 4, a holding clamp serving as an upper side attachment means of an image receptor opened and closed by a shaft 7, a claw 5, and a claw A lower end side clamp, which is a lower side attaching means of an image receptor, which is constituted by a seat 6 and is opened and closed by a shaft 8, is provided. A notch 12 is partially provided on the surface of the impression cylinder 11, and a blanket 13 wound around the surface of the impression cylinder 11 is fixed by a fixing member 14 in the notch. An inclined portion 15 is provided between the partially notched portion 12 and the impression cylinder surface (circumferential surface), and a pin bar 16 is provided. Adhesive tape 17 is applied to the surface of the impression cylinder near the inclined portion 15 where the pin bar 16 is installed on the surface of the impression cylinder and near the other inclined portion of the partially cutout portion.
Is provided.

The image receptor is gripped by the clamp on the side of the transfer cylinder 1. Rotate the transfer cylinder 1 in the direction of the arrow in the figure,
An image receptor (not shown) is gripped by the clamp on the rear side. Preferably, the image receptor is pressed against the surface of the transfer cylinder by an ironing roll (not shown) during rotation so that the image receptor is brought into close contact with the surface of the transfer cylinder. A hole provided on the upper side of the image forming material is inserted into a pin bar 16 provided on the inclined portion 15 of the impression cylinder 11. The holes provided in the image forming material are provided so as to correspond to the pin bars. Next, 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 to the surface of the impression cylinder with the adhesive tape 17. It is preferable that the image forming material is brought into close contact with the surface of the impression cylinder by an ironing roll (not shown) during rotation. It is preferable that the protective film provided on the image forming material be peeled off after the attachment to the impression cylinder. After the attachment of the image receiving material and the image forming material is completed, the transfer cylinder and the impression cylinder are rotated in the direction of the arrow, and the image formed on the photosensitive layer of the image forming material is pressure-transferred to the image receiving material. In a multicolor image, the operation of attaching the image forming material to the impression cylinder is repeated.

FIG. 2 is a schematic sectional view showing a mounting state of the pin bar 16 installed on the inclined portion 15 of the impression cylinder 11. A blanket 13 is wound around the surface of the impression cylinder. The pin bar 16 is mounted on the blanket via an adhesive or an adhesive. A double-sided adhesive tape may be used as the adhesive. A sheet having an adhesive applied to one side provided with a hole corresponding to the pin bar is attached so that the pin of the pin bar projects from the hole. The sticking range is the pin bar and its peripheral portion. The purpose of this sheet is to prevent the pin bar from peeling off from the blanket and to reduce a step formed between the pin bar and the blanket surface. If the step is large, wrinkles are formed on the attached image forming material, and a good transfer image cannot be obtained. The thickness of the pedestal portion of the pin bar is usually about 0.4 mm, and the height of the pin is usually about 1.0 to 5 mm from the pedestal. A sheet having a thickness of about 0.05 to 0.3 mm is used as a sheet for mitigating the occurrence of a step caused by this. As a material for forming the sheet, any material can be used without particular limitation as long as it is a heat-resistant material that can withstand the temperature of the transfer cylinder heated to about 100 ° C. and has a certain degree of dimensional stability. For example, paper, synthetic paper, film and the like.

[0011]

According to the present invention, there is provided an image transfer apparatus provided with a pin bar which can be easily attached and detached and has high positional accuracy. According to the present invention, there is provided an image transfer apparatus that does not require a hole in the blanket and does not require rewinding the blanket when attaching the pin bar. Further, according to the present invention, there is provided an image transfer apparatus in which there is no possibility that the pin bar is distorted when the pin bar is attached.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an image transfer device used in the present invention.

FIG. 2 is a schematic sectional view showing an attached state of a pin bar according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transfer cylinder 11 Impression cylinder 12 Partially notched part 13 Blanket 14 Fixing member 16 Pin bar 18 Adhesive layer 19 Fall-off prevention sheet

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41F 27/00-27/12 B41F 13/10 B41F 16/00

Claims (1)

(57) [Claims] 1. An image forming apparatus comprising: an impression cylinder having an image forming material attached thereto; and a transfer cylinder having an image receptor attached thereto. The image forming material and the image receptor are rotated by rotating the impression cylinder and the transfer cylinder. An image receiving device for transferring an image formed on a photosensitive layer of the forming material to an image receiving member by introducing the image forming member into a nip between the image forming device and the image forming apparatus; An inclined portion provided between the pressure drum surface and the impression cylinder; a blanket wound around the impression cylinder surface; and a pin bar for determining an attachment position of the image forming material attached to the inclined portion. An image transfer device, wherein the image transfer device is attached with an adhesive or a pressure-sensitive adhesive, and is covered with a sheet coated with a pressure-sensitive adhesive on one side provided with holes corresponding to the pins of the pin bar.