JP3262484B2 - 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 a transfer device in an image forming apparatus and the like, and more particularly, to a transfer device having a guide member for guiding a transfer material when an image transfer portion has the transfer material.

[0002]

2. Description of the Related Art Conventionally, in a transfer section of an image forming apparatus, for example, in an apparatus such as a laser printer using electrophotography, an image forming section is a cartridge in which a process unit is integrated, and a toner is provided on a drum in the process cartridge. An image is formed using an image forming member such as. In recent years, in order to transfer an image formed by a known technique to a transfer material (paper), apparatuses using roller transfer in addition to corona transfer have increased.

In an image forming apparatus using such a roller transfer, the transfer roller must be replaced several times during the life of the apparatus main body in order to cope with the high durability of the main body. This is because the life of the transfer roller during roller transfer, such as wear, is shorter than the life of the apparatus main body. FIG. 7 is a cross-sectional view of a transfer section of a conventional image forming apparatus, and replacement of a conventional transfer roller will be described with reference to FIG.

In FIG. 7, reference numeral 101 denotes an image forming process unit, which is a process unit 10 according to a known technique.
A process cartridge 103 for forming a predetermined image on the drum 102 in the printer 1; a process cartridge 103 arranged opposite to the drum 102 for transferring a transfer material (paper) P between the drum 102 and the process cartridge 103;
A transfer roller 104 for transferring an image on the drum 102 formed in the process cartridge 101 onto the sheet P is provided with a rotation center on the axis of the transfer roller 103, and is arranged at a predetermined position. Guide before the transfer from the pre-transfer process to the nip portion between the drum 102 and the transfer roller 103, and 105 is a transfer roller 1
03, a transfer unit for holding and fixing the pre-transfer guide 104, etc., inside the transfer unit 105 for guiding the image transferred onto the paper P at the transfer unit to a fixing device for fixing the image onto the paper. It is configured to include a guide and the like. Reference numeral 106 denotes a hole provided in the transfer unit 105 for catching a hook of the guide 104 before transfer. A is an arrow indicating the direction in which the process cartridge 101 is inserted when the process cartridge 101 is inserted from above the apparatus main body (not shown).

In the above configuration, the pre-transfer guide 104 is replaced with the transfer unit 105 to replace the transfer roller 103.
The nail is removed from the hole 106 of
The pre-transfer guide 104 and the transfer roller 103 are rotated upward about the transfer roller 103 by the transfer unit 105.
At the same time. Next, the transfer roller 103 can be removed by removing the patch portion (locking portion) from the pre-transfer guide 104. Thereafter, the transfer roller 103 for replacement is inserted into the pre-transfer guide 104 for replacement of the transfer roller, and the transfer roller 103 is attached to the apparatus transfer unit in a procedure reverse to that when the transfer roller 103 is removed. At this time, it is necessary that the claw of the transfer guide 104 is securely caught in the hole 106 in the transfer unit 105. This is for accurately guiding the sheet P to a predetermined nip portion.

[0006]

However, the above-mentioned prior art has the following problems.

The transfer roller 103 described in the above conventional example
At the time of replacement, the pre-transfer guide 104 is attached to and detached from the transfer unit 105. At this time, the operator forgets to securely insert the hook of the pre-transfer guide to a predetermined position, and as a result, the solid line shown in FIG. In some cases, the pre-transfer guide may be located at the position. In such a case, the pre-transfer guide is closer to the process cartridge than the predetermined position, so that a predetermined paper path cannot be secured, resulting in a paper jam. or,
Guide 1 before transfer in the wrong state as described above
04, and insert the process cartridge,
The pre-transfer guide 103 abnormally interferes with a part of the process cartridge, and has a drawback that the process cartridge, particularly the photoconductor, may be damaged such as scratches or dents.

[0008]

According to the present invention, a nip portion is formed between an image carrier and an image carrier, and an image is transferred from the image carrier to a transfer material passing through the nip portion. A transfer roller, a transfer member that guides the transfer material when there is a transfer material in the nip, and a guide member that is rotatably provided around a rotation axis of the transfer roller;
When the guide member is not fixed at a predetermined position, the guide member has an elastic member that presses and rotates the guide member. When the guide member is not fixed at the predetermined position, the guide member is configured such that the image carrier is an image forming apparatus. It is characterized in that it is prohibited to be arranged at a predetermined position.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1, 2, 3, 5, and 6 show the transfer unit of the image forming apparatus of the present invention and the structure before and after the transfer unit, and FIG. A process cartridge for forming an image using a known process technology, a photosensitive drum 2 as an image carrier that is disposed in the process cartridge and forms an image by holding a developer such as toner on the outer periphery; A roller that forms a nip between the drum 2 and the drum 2. The roller is held at both ends by bearings and is configured to contact the outer periphery of the drum 2 with an appropriate pressing force. A transfer roller for transferring the upper image onto the transfer material P.
Reference numeral 4 denotes a pre-transfer guide, which is a guide that guides the transfer material P to the nip portion between the drum 2 and the transfer roller 3 while fixing the other with the hook 17 around the axis of the transfer roller 3 as the rotation center.
5 is a transfer roller bearing fitted in the pre-transfer guide 4, 6 is a transfer table supporting and fixing the transfer roller 3 and the like, and 7 is a leaf spring fixed to the transfer table 6 to lift the pre-transfer guide 4 upward. , 8 are provided on the transfer table 6 and are hook holes for hooking hooks of the pre-transfer guide 4, 9 are guide ribs for guiding the transfer material P to the next step of transfer, and 10 is a comb between the guide ribs 9. A transfer guide plate 11 provided in a rib shape is used to transfer an image on the transfer material P to the transfer material P.
A heat fixing device 12 for fixing the transfer material P temporarily stops the leading end of the transfer material P in a pre-transfer process, corrects the skew of the transfer material P, and then nips the drum 2 and the transfer roller 3 at a predetermined timing. This is a registration roller unit for transporting the transfer material P to the unit. 15 is a bearing of the transfer roller 3 for pressing the transfer roller 3 against the drum 2;
Is a pressure spring that urges the bearing 15 toward the drum 2. The bearing 15 and the pressure spring 16 are provided at both ends of the shaft of the transfer roller 3, so that the transfer roller 3 and the drum 2 are uniformly contacted in the longitudinal direction.

In the above configuration, the transfer roller 3
The following describes the replacement of the. First, the transfer roller 3 is lifted and removed from the holding portion of the transfer table 6. At the same time as this operation, the pre-transfer guide 4 has its rotation center on the axis of the transfer roller 3, so that the claw 17 at the rear end comes out of the hole 8 of the transfer table 6 while moving upward on the transfer roller side. As a result, both the transfer roller 3 and the pre-transfer guide 4 are removed outside the image forming apparatus. Next, since the transfer roller 3 is patched to the transfer bearing 5 of the pre-transfer guide 4, it is removed. As a result, the transfer roller 3 can be replaced by itself. Thereafter, the new transfer roller 3 is patched to the pre-transfer guide 4 and attached to the image forming apparatus main body by the reverse operation of removing the transfer roller 3 from the image forming apparatus main body.

At this time, if the operator forgets to insert the patch pawl 17 of the pre-transfer guide 4 into the hole 8 of the transfer table 6, the leaf spring 7 as an elastic member disposed below the guide is moved to the position indicated by the solid line in FIG. The pre-transfer guide 4 is lifted up to the position. As described above, the operator can easily notice that the transfer guide is not attached to a normal position by rotating the pre-transfer guide upward. However, if the operator does not notice the abnormal position and inserts the process cartridge 1 into the main body, the drum 2 in the process cartridge 1 is moved by the pre-transfer guide as shown in FIG. It is configured so as to interfere with and hit an end (butting portion). Therefore, since the process cartridge 1 is not inserted to the predetermined position, the lid as a cover of the opening of the process cartridge 1 in the image forming apparatus main body is not closed, and the apparatus does not enter the ready state in which the image forming operation can be performed. That is, a sensor for detecting the opening and closing of the lid is provided, and the image forming operation is prohibited unless the lid is closed. By doing so, even if an operator causes an error when attaching the pre-transfer guide 4, the main body does not operate, so that the operator can notice abnormalities. Therefore, the operator notices that the guide 4 has been erroneously arranged, and after assembling the guide 4 at a correct predetermined position, the image forming apparatus can be restarted.

(Second Embodiment) FIG. 4 shows another embodiment of the present invention. In FIG. 4, reference numeral 13 denotes an elastic member disposed at an end of an outer peripheral portion remote from the rotation center of the pre-transfer guide 4. The elastic member 13 is colored yellow. The provision of the elastic member 13 allows the pre-transfer guide 4
4 is lifted by the leaf spring 7 to the position shown in FIG. 4 when it is not fixed at a predetermined position, so that the drum 2
Hit. The drum 2 in the process cartridge 1 can be prevented from being damaged, and at the same time, since the elastic member 13 is colored yellow, the pre-transfer guide 4 is arranged at a normal position for the operator. You can give a warning that something has not been done.

The process cartridge according to the first and second embodiments may include a photosensitive drum and at least one of a charger, a developing device, and a cleaner acting on the photosensitive drum.

[0014]

As described above, according to the present invention,
The operator can easily find and know the assembly error of the guide member that has occurred when the transfer roller is replaced. Also, especially when the operator inserts the process cartridge into the main body of the image forming apparatus without arranging the guide member in the correct position, the main body of the image forming apparatus does not enter the ready state. Can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a perspective view of the vicinity of an image transfer unit of an image forming apparatus according to the present invention.

FIG. 2 is a perspective view of the vicinity of an image transfer unit of the image forming apparatus of the present invention.

FIG. 3 is a cross-sectional view near an image transfer unit of the image forming apparatus of the present invention.

FIG. 4 is a cross-sectional view of an image forming apparatus according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view near an image transfer unit of the image forming apparatus of the present invention.

FIG. 6 is a cross-sectional view near an image transfer unit of the image forming apparatus of the present invention.

FIG. 7 is a cross-sectional view of an image forming apparatus illustrating a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 process cartridge 2 drum 3 transfer roller 4 pre-transfer guide 5 transfer roller bearing 6 transfer table 7 leaf spring 8 claw hook hole 9 guide rib 10 transport guide 11 heat fixing device 12 registration roller unit 13 elastic member 15 bearing 16 pressure spring 17 claw

Claims (2)

(57) [Claims] A transfer roller that forms a nip between the image carrier and a transfer material that transfers an image from the image carrier to a transfer material that passes through the nip; and a transfer material when the nip has a transfer material. And a guide member rotatably provided around a rotation axis of the transfer roller. In the transfer device, when the guide member is not fixed at a predetermined position, the guide member is pressed and rotated. A transfer device having an elastic member, wherein the guide member prohibits the image carrier from being disposed at a predetermined position of the image forming apparatus when the guide member is not fixed at a predetermined position. 2. The transfer apparatus according to claim 1, wherein when the guide member is not fixed at a predetermined position, the guide includes a part of another elastic member that contacts the image carrier.