JPH07120994A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of upper curl and to eliminate jamming caused by separation failure by providing a heat source device in the vicinity of a lower resist roller and warming the lower surface of a transfer material when the transfer material passes a resist roller. CONSTITUTION:When the copy start key of the operation part of a copying device main body 1 is depressed, transfer paper 4 as the transfer material is fed from an upper cassette 2 (or lower cassette 3). The transfer paper 4 fed is sent by a upper vertical carrying roller 7 (or lower vertical carrying roller 8) and is stopped at a position where its leading edge is caught between upper and lower resist rollers 9 and 10. Then, the upper and the lower resist rollers 9 and 10 start to move in timing with scanning of an optical system 21, and the image is transferred at the appropriate image position of the transfer paper 4. A copying device 1 is provided with a heater 15 inside the lower resist roller 10 and the transfer paper 4 is warmed up by it when the transfer paper 4 passes the resist rollers 9 and 10, so that the moisture of the lower surface of the transfer paper 4 is evaporated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a facsimile, and more particularly to prevention of curling of a transfer material by a nip portion of a registration roller.

[0002]

2. Description of the Related Art A main sectional view of a conventional copying machine is shown in FIG. 5, and an enlarged view of a portion B in FIG. 5 is shown in FIG. In FIG. 5, 3
1 is a copying apparatus main body, 32 is an upper cassette, 33 is a lower cassette, 34 is a transfer sheet as a transfer material, 35 is an upper paper feeding roller, 36 is a lower paper feeding roller, 37 is a vertical conveying roller,
38 is a vertical conveyance roller lower, 39 is an upper registration roller,
40 is a lower registration roller, 41 is a transfer guide, 42 is a photosensitive drum, 43 is a transfer charger, 44 is a discharging needle, 47 is a separation sensor, 48 is a transport unit, 49 is a fixing device, and 51 is an optical system.

The operation when a copy operation is performed in the copying apparatus having the above-mentioned structure will be described below. First, when a copy start key (not shown) of the operation unit of the copying apparatus main body 31 is pressed, the upper paper feeding roller 35 (or the lower paper feeding roller 36) is activated, and the upper cassette 32
The transfer paper 34 is fed from (or the lower cassette 33). The transferred transfer paper 34 is placed on the vertical transport roller 37.
(Or under the vertical transport roller 38) and stops when the tip is sandwiched by the upper and lower registration rollers 39, 40. Then, the upper and lower registration rollers 39, 40 start moving at the same timing as the optical system 51 scans, and the image is transferred to the proper image position on the transfer paper 34. After that, the transfer paper 34 is discharged through the transport unit 48 and the fixing device 49.

The upper resist roller 39 is a metal roller, and the lower resist roller 40 is a rubber roller. As shown in FIG. 7, after applying the transfer paper 34 in the vicinity of the nip portion of the upper registration roller 39, the upper registration roller 39 is slid and sandwiched between the upper and lower registration rollers 39 and 40 to transfer the paper 34. It is intended to stabilize the transportability of.

[0005]

However, in the above-described conventional copying apparatus, when the transfer paper 34 passes through the upper and lower registration rollers 39 and 40, the transfer paper 34 is at the nip portion as shown in FIG. Since curling causes an upward curl, electrostatic separation by the charge eliminating needle 44 is not sufficient, and there is a drawback that particularly in thin paper, the separation sensor 47 is easily skipped to cause a separation failure jam.

The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to prevent curling of the transfer material by the nip portion of the registration roller,
It is an object of the present invention to provide a copying apparatus that can sufficiently perform electrostatic separation and that does not have a separation failure jam.

[0007]

In order to achieve the above object, the present invention has an image carrier and a registration roller provided on the upstream side of the image carrier in the transport direction, A heat source device is provided in the vicinity of the registration roller.

Further, it is preferable that the heat source device is a heater and is provided inside the resist roller.

[0009]

In the copying apparatus constructed as described above, since the heat source device is provided in the vicinity of the resist roller, the transfer material is warmed when the transfer material passes through the resist roller.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

(First Embodiment) FIG. 1 is a sectional view of a copying machine as an image forming apparatus according to the present invention, and FIG. 2 is an enlarged view of portion A of FIG. In FIG. 1, 1 is a copying apparatus main body,
2 is an upper cassette, 3 is a lower cassette, 4 is a transfer paper as a transfer material, 5 is an upper paper feeding roller, 6 is a lower paper feeding roller, 7
Is a vertical transport roller, 8 is a vertical transport roller, 9 is an upper registration roller, 10 is a lower registration roller, 11 is a transfer guide, 12 is a photosensitive drum as an image carrier, 13 is a transfer charger, and 14 is a static elimination needle. Reference numeral 15 is a heater as a heat source device, 17 is a separation sensor, 18 is a transport unit, 19 is a fixing device, and 21 is an optical system.

The operation when a copy operation is performed in the copying apparatus having the above-mentioned structure will be described below. First, when a copy start key (not shown) of the operation unit of the copying apparatus main body 1 is pressed, the upper paper feed roller 5 (or the lower paper feed roller 6) is activated, and the upper cassette 2 (or the lower cassette 3) transfers a transfer sheet as a transfer material. 4 is fed. The fed transfer paper 4 is sent on the vertical transport roller 7 (or the vertical transport roller lower 8), and stops when the leading end is sandwiched by the upper and lower registration rollers 9 and 10. The upper and lower registration rollers 9 and 10 start moving at the same timing as the optical system 21 scans, and the image is transferred to the proper image position on the transfer paper 4. Here, in the copying apparatus 1 according to the present invention, the heater 15 is provided inside the lower registration roller 10, and the water on the lower surface of the transfer paper 4 evaporates by this, so that the heater 15 on the transfer paper shown in the conventional example can be used. Curling can be prevented. Therefore, as shown in FIG. 2, it is possible to stably carry the paper without a separation failure jam. After that, the transfer paper 4 is discharged through the transport unit 18 and the fixing device 19.

(Second Embodiment) FIG. 3 is a main sectional view around a photosensitive drum 12 of a copying machine according to a second embodiment of the present invention.

In FIG. 3, a heater 15 is provided outside the lower resist roller 10 and the surface of the lower resist roller 10 is heated to obtain the same effect as that of the first embodiment.

(Third Embodiment) FIG. 4 is a sectional view around the photosensitive drum 12 of a copying machine according to the third embodiment of the present invention.

In FIG. 4, 24 is a ceramic heater as a heat source device, and 25 is a metal plate.
Reference numeral 5 has a shape surrounding the lower registration roller 10. Therefore, the heat of the ceramic heater 24 causes the metal plate 25 to
Is heated, and the surface of the lower resist roller 10 is further heated, so that the same effect as that of the first embodiment can be obtained.

[0017]

According to the present invention having the above-described structure and operation, since the heat source device is provided in the vicinity of the lower resist roller, when the transfer material passes through the resist roller, the lower surface of the transfer material is warmed and the upper curl is curled. Is prevented from occurring. As a result, it is possible to provide an image forming apparatus in which electrostatic separation is sufficiently performed and a separation failure jam does not occur.

[Brief description of drawings]

FIG. 1 is a sectional view showing an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing an image forming apparatus that is a first embodiment of the present invention.

FIG. 3 is a cross-sectional view of essential parts showing an image forming apparatus that is a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing an image forming apparatus that is a third embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional image forming apparatus.

FIG. 6 is a cross-sectional view of essential parts showing a conventional image forming apparatus.

FIG. 7 is a schematic view of a nip portion of a registration roller applied to a conventional image forming apparatus.

[Explanation of symbols]

 1,31 Copying device main body 4,34 Transfer paper (transfer material) 9,39 Upper registration roller 10,40 Lower registration roller 12,42 Photosensitive drum (image carrier) 15 Heater (heat source device) 24 Ceramic heater (heat source device)

Claims (2)

[Claims] 1. An image forming apparatus comprising: an image bearing member; and a resist roller provided on the upstream side of the image bearing member in the conveying direction, and a heat source device provided near the resist roller. 2. The heat source device is a heater and is provided inside the resist roller.
The image forming apparatus according to item 1.