JPH04189248A - Paper discharge device for image forming device - Google Patents

Abstract

PURPOSE:To improve the stacking property of sheets on a paper discharge tray by giving a tension to a sheet by a major diameter part and a concave part provided on a vertical pair of discharge rollers, respectively. CONSTITUTION:A sheet curled to protrude downward by a discharge presser roller pressed into contact with a lower discharge roller 72 is carried along the outer circumferential surface of the lower discharge roller 72, and during this carriage, the sheet is curled to protrude upward. Thus, the curl of the sheet is corrected. Further, the sheet is nipped between a large diameter part 74 and a concave part 75 on the upper and lower discharge rollers 71, 72. Thus, a tension is given to the sheet.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a photosensitive sheet coated with microcapsules containing a photocurable material and a color-forming dye, and a developer that develops color by reacting with the color-forming dye. This invention relates to a paper discharging device used in an image forming apparatus that forms an image by pressing stacked image receiving sheets coated with a material, and discharging the image receiving sheets after the image has been formed and passed through a glossing device. .

(Prior Art) For example, JP-A-58-88739 discloses a photosensitive sheet coated with microcapsules containing a photocurable material and a coloring dye, and a developing material that develops color by reacting with the coloring dye. An image forming apparatus that forms an image using an image receiving sheet coated with is disclosed.

In such an image forming apparatus, an image is formed in the following manner. First, when an original image is exposed to light on a photosensitive sheet, the microcapsules in the portions irradiated with light are selectively hardened, and a latent image corresponding to the original image is formed. The photosensitive sheet on which the latent image has been formed is placed on the image receiving sheet coated with a developing material in a pressure device, which is a pressure development section, and both are pressed together. As a result, the uncured microcapsules on the photosensitive sheet are destroyed, and the coloring dye contained therein flows out, and the flowing out coloring dye reacts with the developing material on the image-receiving sheet to form a color. As a result, an image corresponding to the original image is formed on the image receiving sheet. The image-receiving sheet on which the image has been formed is conveyed to a glossing device, where it is pressurized and heated to make the image surface glossy, and then it is sandwiched between a pair of upper and lower paper ejection rollers of a paper ejection device. The paper is then conveyed and ejected onto the paper ejection tray.

(Problems to be Solved by the Invention) In such an image forming apparatus, the coated image receiving surface of the image receiving sheet is heated in the glossing device, so that the image receiving sheet curls so as to wrap the image receiving surface inward. There is a risk that this may occur. The curled image receiving sheet is then discharged in a curled state onto a paper discharge tray by a paper discharge device.

The present invention is intended to solve these problems, and an object thereof is to provide a paper ejecting device for an image forming apparatus that can correct an image receiving sheet curled by a glossing device to a state in which the curl is eliminated. It is in.

(Means for Solving the Problems) The discharging device of an image forming apparatus of the present invention is used in an image forming apparatus in which a sheet is heated and pressurized after an image is formed on the sheet by a developer. and a sheet discharge device for discharging the sheet, which is conveyed in a curled state protruding downward under pressure, to the outside, the sheet being pressed against each other so as to sandwich the sheet and convey it in the sheet discharge direction; A pair of upper and lower sheet ejection rollers are provided with a large-diameter portion in which a portion of the sheet has a large diameter in the axial direction, and the other is provided with a concave portion into which the large-diameter portion fits; A paper ejection pressing roller is provided which is pressed against an upper position of the lower paper ejection roller on the upstream side in the transport direction so as to convey the paper along the outer circumferential surface of the lower paper ejection roller to the pressure contact position of the roller. , thereby achieving the above objective.

(Function) In the paper ejection device of the image forming apparatus of the present invention, the sheet curled so as to protrude downward is moved by the paper ejection pressing roller that is in pressure contact with the lower paper ejection roller. The curl of the sheet is corrected by being conveyed along the outer peripheral surface of the sheet and curled so as to protrude upward during the conveyance.

Furthermore, tension is imparted to the sheet by being sandwiched between the large diameter portion and the concave surface portion of the upper and lower paper ejection rollers.

(Example) Examples of the present invention will be described below.

FIG. 2 is a front longitudinal cross-sectional view of a copying machine having a paper discharge device of the present invention. This copying machine has a glass document mounting table 2 provided on the top surface of a copying machine main body 1. A document 3 for forming a copy image is placed on the document table 2 . A manual paper feed section 5 and a paper feed cassette 6 are provided on one side of the copying machine main body 1. The paper feed cassette 6 accommodates, for example, an image receiving sheet 7 coated with an acidic developing material. This image-receiving sheet 7 is overlapped with a photosensitive sheet and developed under pressure.
An image is formed on the image receiving sheet 7. Further, on the other side of the copying machine main body 1, there is provided a paper discharge tray 8 on which the image receiving sheet 7 on which an image has been formed is placed.

An optical system 10 is provided at the top of the copying machine main body 1. The optical system 10 has a pair of light sources 11 and 12 that irradiate light onto a document 3 placed on a document table 2 on the top surface of the copying machine main body 1.
It is capable of reciprocating movement in the direction shown by arrow C and in the opposite direction. The original 3 is illuminated by both light sources 11 and 12.
The light reflected from the mirror 13 is reflected in the direction opposite to the direction indicated by the arrow C by the mirror 13, which moves together with the light sources 11 and 12. The traveling direction of the light reflected by the mirror 13 is reversed by a pair of reflecting mirrors 15 and 16 inside the mirror case 14. The light whose traveling direction is reversed by a pair of mirrors 15 and 16 passes through a lens unit 17, is reflected by a mirror 18, and is irradiated toward an exposure plate 30 provided approximately in the center of the copying machine main body l. be done.

A photosensitive sheet packet 20 is arranged below the mirror case 14. Packet 20 for the photosensitive sheet
A cartridge 21 covered with a case made of a light-shielding material is attached to the holder. This cartridge 21 has a roll-shaped photosensitive sheet 23 that is wound around an internal supply shaft 22 and housed therein. The photosensitive sheet 23 is a base sheet made of metal, synthetic resin, or the like, coated with microcapsules that are a photosensitive pressure-sensitive material having a particle size of about 10 to 20 μm and containing a coloring dye such as a leuco dye and a photocurable substance. has been done.

Positioning holes (not shown) used for sequentially feeding out the photosensitive sheets 23 from the photosensitive sheet packet 20 are provided along the longitudinal direction on both sides of the photosensitive sheet 23 in the width direction. The tractor roller 24 is sequentially fitted into the positioning hole. Power is transmitted to the tractor roller 24 via a clutch (not shown), and the photosensitive sheet 23 is fed out from the photosensitive sheet packet 20 and conveyed to the exposure plate 30 by the tractor roller 24. .

The exposure plate 30 is arranged to be orthogonal to the light reflected by the mirror 18 in the optical system 10, and the photosensitive sheet 23 is conveyed along the surface facing the mirror 18. A heater 31 is attached to the surface of the exposure plate 30 opposite to the surface on which the photosensitive sheet 23 is conveyed, and the exposure plate 30 is kept at a predetermined temperature by the heater 31. The photosensitive sheet 23 being conveyed along the line is brought to a predetermined temperature. Thereby, the sensitivity of the photosensitive sheet 23 is maintained at a predetermined state.

The photosensitive sheet 23 conveyed along the exposure plate 30 is irradiated with reflected light from the original 3 by the optical system 10 .

As a result, the microcapsules on the photosensitive sheet 23 are selectively photocured, and a latent image corresponding to the original image is formed on the photosensitive sheet 23.

Further, the light-transmitting sheet projection section 4 provided on the side surface of the copying machine main body 1 is in a state facing the exposure plate 30.
When copying an image on a light-transmitting sheet, the optical system lO
The mirror 18 is moved so that the light projected from the light-transmissive sheet projection section 4 is directly irradiated onto the photosensitive sheet 23 conveyed along the exposure plate 30.

Near the lower end of the exposure plate 30, a guide roller 32 and a buffer roller 33 are provided in order along the conveyance direction of the photosensitive sheet 23. The guide roller 32 is disposed so as to face the microcapsule-coated surface of the photosensitive sheet 23 being conveyed. The buffer roller 33 is movable from a home position facing the back surface of the photosensitive sheet 23 in the directions of arrows A and B perpendicular to the exposure plate 30. Exposure plate 30
The photosensitive sheet 23 conveyed along the buffer roller 33 is wound around the buffer roller 33, and its direction is directed toward the photosensitive sheet packet 20 side. buffalo 33
The photosensitive sheet 23 wound around the photosensitive sheet 23 passes through a pressurizing device 50 and is attached to the winding shaft 25 of the photosensitive sheet packet 20.
It is wound up.

The buffer roller 33 is rotatable in both forward and reverse directions, and is moved from the home position 1 in the direction of arrow A to a pull-out position 33a shown by a broken line. By moving the buffer roller 33 to this pull-out position 33a, the photosensitive sheet 23 is pulled out by a predetermined length.

An image receiving sheet 7 conveyed by a conveyance mechanism 40 is fed to a pressure device 50, which is a pressure development section, from a manual paper feed section 5 or a paper feed cassette 6 provided on the side of the copying machine main body 1. . The image-receiving sheet 23 is supplied to the pressure device 50 by the transport mechanism 40 in synchronization with the photosensitive sheet 23 on which a latent image is formed by exposure while being transported along the exposure plate 30. .

In the pressurizing device 50, the image receiving sheet 7 and the photosensitive sheet 23 on which the image has been exposed are pressed in a superposed state,
As described above, only the uncured microcapsules that have not been cured by light are destroyed, and the photosensitive sheet 23
Color-forming dyes such as heloco dyes flow out from the image-receiving sheet 7,
The coloring dye and the developing material of the image-receiving sheet 7 react to form an image on the image-receiving sheet 7. The image-receiving sheet 7 developed by the pressure device 50 in this way is conveyed to the glossing device 60 via the drawing roller 55, and is pressurized and heated by the glossing device 60 to give the image a glossy appearance. will be granted. The glossy image receiving sheet 7 is discharged onto the paper discharge tray 8 of the copying machine main body l by a paper discharge device 70 disposed on the paper discharge tray 8 side of the glossing device 60.

The glossing device 1160 and paper ejecting device 70 will be explained with reference to FIG.

The glossing device 60 includes a heat roller 61, a tension roller 62, a glosser belt 63, and a pressure roller 6.
It has 4. The heat roller 61 and tension roller 62 are arranged at a predetermined distance apart along the conveyance path of the image receiving sheet 7, and a glosser belt 63 is wound around the heat roller 61 and tension roller 62. ing. heat roller 6
1 is heated by a heater such as a halogen lamp disposed inside, and the heat of this heat roller 61 is almost uniformly transmitted to a heat-resistant glosser belt 63.

Below the heat roller 61, the heat roller 61
A pressure roller 64 is provided which presses the glosser belt 63 wound around the heat roller 61 against the heat roller 61. When the sheet 7 is conveyed, the developing sheet 7 is pressurized and heated.

An image is formed on the image-receiving sheet 7 using a color-forming dye, and heating accelerates the color-forming reaction of the dye, resulting in a clear image. Further, the image receiving sheet 7 is coated with a thermoplastic resin in advance, and when heated, the resin becomes softened and melted, and the sheet surface is covered with the resin, and when further pressurized, the resin becomes smooth. to add gloss to the image. The heat roller 61
The image receiving sheet 7, which has passed between the glosser belt 63 and the pressure roller 64, is further wrapped around the glosser belt 63 and the pressure roller 64.
The paper is conveyed along the belt 63 to the paper discharge device 70.

The image receiving sheet 7 is cooled while being conveyed by the glosser belt 63 and separated from the glosser belt 63 wound around the tension roller 62. The separated image receiving sheet 7 is sent to a paper discharge device 70.

The paper ejection device 70 includes a pair of upper and lower ejection rollers 71 and a lower ejection roller 72 that are in pressure contact with each other, and a paper ejection pressing roller 73 that is disposed on the glossing device 60 side of the lower ejection roller 72. ing. The upper paper ejection roller 71 is
As shown in FIG. 1, large diameter portions 74 and 74 whose outer circumferential surfaces are curved in an arc shape are formed at two locations sandwiching the central portion in the elongated direction, and the lower paper ejection roller 72 has large diameter portions 74 and 74 formed on both sides of the central portion in the elongated direction. Diameter 7
Concave portions 75 and 75 are formed with which 4 is in pressure contact.

The upper paper ejection roller 71 has a diameter of approximately 12 mm excluding each large diameter portion 74, and the lower paper ejection roller 7
2 has a diameter of approximately 2011II11 excluding each concave surface portion 75.
is set to . The lower paper discharge roller 72 is made of neoprene rubber having a hardness of 65 to 70 degrees.

The paper ejection pressing roller 73 is located on the glossing device 60 side of the lower paper ejection roller 72.
The center angle θ with respect to the horizontal line is pressed against the outer circumferential surface position of about 40°. The paper ejection pressing roller 73 is
It is supported by a paper discharge pressing plate 77 disposed between the tension roller 62 in the glossing device 60 and above the image-receiving sheet being conveyed. The paper ejection pressing roller 73 is
For example, it is made of steel, is sufficiently smaller than the lower paper ejection roller 72, and has a diameter of about 611II11.

In a copying machine having such a configuration, the glossing device 60 heats the coloring dye, thermoplastic resin, etc. applied to the upper surface of the image-receiving surface of the image-receiving sheet 7, so that the image-receiving sheet 7 is lowered. It is curled so that it sticks out.

The image receiving sheet 7 curled in this manner is fed to the paper discharge device 70 and is sandwiched between the lower paper discharge roller 72 and the paper discharge presser roller 73. Then, the lower paper ejection roller 72
The image receiving sheet 7 that has passed between the
is moved along the upper circumferential surface of the lower paper ejection roller 72 and is conveyed to a position where it comes into pressure contact with the upper paper ejection roller 71. After being brought into pressure contact with both paper discharge rollers 71 and 72, the paper is discharged onto the paper discharge tray 8.

The image receiving sheet 7 that has passed through the pressure contact position between the paper ejection pressing roller 73 and the lower paper ejection roller 72 is moved to the lower paper ejection roller 72.
In order to be conveyed along the upper circumferential surface of the paper sheet, the paper sheet is curled so as to protrude upward by the circumferential surface of the lower paper discharge roller 72 . Therefore, the image-receiving sheet that has passed through the glossing device 60 and is curled so as to protrude downward can be
While passing through, it is made to curl in the opposite direction,
The curl caused by the brightening device 60 is corrected.

Further, when the image receiving sheet 7 passes between the upper paper ejection roller 71 and the lower paper ejection roller 72, each large diameter portion 74 of the upper paper ejection roller 71 and each concave surface portion of the lower paper ejection roller 72 are Since tension is applied to the image receiving sheet 7 by the image receiving sheet 75, stiffness is imparted to the image receiving sheet 7, and stackability on the paper discharge tray 8 is improved.

(Effects of the Invention) In the sheet discharge device of the image forming apparatus of the present invention, the sheet on which the image is formed and is curled is discharged to the outside with the curl corrected.

Moreover, the large diameter portion and concave surface portion provided on each of the upper and lower pair of paper ejection rollers provide tension to the sheet, thereby improving the stackability of the sheet on the paper ejection tray.

4,'. Fig. 1 is a side view of a paper ejection roller which is an example of the paper ejection device of the present invention, Fig. 2 is an internal configuration diagram of a copying machine using the paper ejection device of the present invention, and Fig. 3 is a side view of a paper ejection roller that is an example of the paper ejection device of the present invention. FIG. 2 is an enlarged view showing a glossing device and a paper ejecting device.

Claims (1)

[Claims] 1. After an image is formed on a sheet using a developer, the sheet is used in an image forming apparatus that heats and presses the sheet, and is conveyed in a curled state that protrudes downward due to the heating and pressurization. A paper ejecting device that ejects the sheets to the outside, which are pressed against each other so that the sheets are sandwiched and conveyed in the ejecting direction, and one part has a large diameter in the axial direction. A pair of upper and lower paper ejection rollers each having a large-diameter portion and a concave portion into which the large-diameter portion fits; A paper ejecting device for an image forming apparatus, comprising: a paper ejecting presser roller that is pressed against an upper position of a lower paper ejecting roller on the upstream side in a conveyance direction so as to convey the paper along an outer circumferential surface.