JPH0682429U - Image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object to provide an image forming apparatus that forms a high quality image by using a driving roller having a simple shape, a high yield in mass production, and high precision. . In an image forming apparatus equipped with a mechanism for conveying an image sheet or the like 6 by driving a drive roller,
The drive roller 1 has a circular portion 2 at the center in the axial direction, a non-circular portion 3 at least at one end in the axial direction, and a cutout portion 4 between the circular portion and the non-circular portion. The non-circular portion of the roller and the rotational driving force transmitting means 5 are engaged with each other to transmit the rotational driving force to the driving roller, whereby the image sheet or the like is conveyed and driven.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to an image forming apparatus using a driving roller used to convey and drive an image sheet or the like to form an image.

[0002]

[Prior art]

 The drive roller in the conventional image forming apparatus is a conveyance drive roller used for conveying an image sheet or the like, or a nip formed by a fixing roller and a pressure roller for an image sheet holding an unfixed toner image in the image forming unit. Some of them are used for a pair of fixing rollers of a fixing device that conveys the toner to an image sheet and fuses the toner onto the image sheet by heat fusion. FIG. 3 is a perspective view showing a partial configuration of a conventional image forming apparatus, and FIG. 4 is a plan view thereof. The fixing roller pair of the fixing device in the image forming apparatus will be described with reference to FIGS. 3 and 4. The fixing roller pair of the driving roller 101 is composed of a fixing roller 101a for heating which is rotationally driven and a pressure roller 101b, and the image sheet 106 to be fixed is sandwiched by the nip portion 107 between both rollers, and the image sheet 106 is held. The unfixed toner transferred to the image sheet 106 is fixed by applying heat and pressure to the.

In the fixing roller pair as the driving roller 101 in such a fixing device, the driving force is transmitted to the heating fixing roller 101a through a motor (not shown) and an intermediate transmission means (rotational driving force). This is realized by fitting the non-circular hole 105a of the transmission means 105 and the non-circular portion 103 at the end of the fixing roller 101a. The non-circular portion 103 at the end of the fixing roller 101a is formed into a D shape as shown by a cutting process such as a milling process. However, as the fixing roller 101a has been made thinner due to the demands for downsizing, weight saving, and cost reduction of the fixing device, the end of the fixing roller 101a may be cut by the cutting process such as the milling process as described above. Since it is difficult to obtain the non-circular portion 103 of the portion, the D-shape as shown in the above figure is manufactured by drawing such as pressing. At the time of the drawing process, distortion or bulge due to stress occurs between the circular portion 102 and the non-circular portion 103, and in particular, the circular portion 102 is affected by the stress on the circular portion 102 and the roundness deteriorates. Was aggravating the non-retention of. Further, when such a driving roller is used for a conveyance driving roller used for conveying an image sheet or the like, the fixing roller pair, etc., there is a problem that the image quality is deteriorated.

[0004]

[Problems to be solved by the device]

 The thin-walled drive roller used in the conventional image forming apparatus has poor circularity and poor retention during mass production, and has a problem that the quality of the formed image is deteriorated.

[0005]

[The purpose of the device]

 Therefore, the present invention solves such a problem. That is, it is an object of the present invention to provide an image forming apparatus which forms a high quality image by using a driving roller having a simple shape, a high yield in mass production and a high precision.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides an image forming apparatus that drives a drive roller to convey and drive an image sheet or the like to form an image. It has a non-circular portion at one end and a cutout portion provided between the circular portion and the non-circular portion, and the non-circular portion of the drive roller engages with the rotary drive force transmitting element so that The main features are an image forming apparatus that conveys and drives an image sheet or the like to form an image by transmitting a rotational driving force to a driving roller, and that the cutout portion is a cutout hole.

[0007]

With the image forming apparatus configured as described above, distortion or bulge due to stress does not occur between the circular portion and the non-circular portion of the drive roller, or the circular portion has a simple shape and is suitable for mass production. An image forming apparatus that forms a high-quality image can be provided by using a high-precision drive roller that has a high yield.

[0008]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are a perspective view and a plan view showing a main configuration (fixing device) of an image forming apparatus according to an embodiment of the present invention. An electrophotographic image (not shown in FIGS. 1 and 2). The image sheet 6 having the unfixed toner image conveyed from the transfer portion of the forming device is guided by an entrance guide plate (not shown) and heated and pressed in the fixing device. This fixing device is composed of a fixing roller 1a which is a driving roller 1 and a pressure roller 1b. The fixing roller 1a has a heater 8 built therein and is formed between the pressure roller 1b which is rotatably pressed. The toner image is fixed by heating by sandwiching the image sheet 6 in the nip portion 7 formed. The image sheet 6 after fixing is peeled off from the fixing roller pair by a separation claw (not shown), and is discharged from the fixing device by a sheet discharge guide plate (not shown). The image sheet 6 to be fixed is sandwiched by the nip portion 7 between the fixing roller 1a as the driving roller 1 and the pressure roller 1b, and heat and pressure are applied to the image sheet 6 to transfer it to the image sheet 6. Unfixed toner is fixed.

In such a fixing device, the driving force is transmitted to the fixing roller 1a by a drive gear (rotational driving force transmitting means) 5 and a non-circular end portion of the fixing roller 1a through an unillustrated motor and an intermediate transmitting means. Part 3 is sequentially performed. The fixing roller 1a of the drive roller 1 has a circular portion 2 at the central portion in the axial direction, a non-circular portion 3 having a D-shape as shown in the axial end portion, and further, the circular portion 2 and the non-circular portion 3 And a cutout portion 4 is formed between and. The cutout portion 4 may be a cutout hole 4a as illustrated. When the flat portion 3a of the non-circular portion 3 of the fixing roller 1a and the non-circular hole 5a of the drive gear 5 as the rotational driving force transmitting means are fitted to each other, the rotational driving force is transmitted to the fixing roller 1a of the driving roller 1. You can do it.

The non-circular portion 3 at the end of the fixing roller 1a is manufactured by cutting a thin material by D-shaped milling as shown in the drawing, or by press working. Even when it is manufactured by drawing, since the cutout portion 4 or the cutout hole 4a is provided between the non-circular portion 3 and the central portion of the fixing roller, the circular portion 2 and No strain or bulge due to stress occurs between the non-circular portions 3. Therefore, the circular portion 2 is not affected by the stress, and the circularity is not deteriorated, the inconvenience during mass production is aggravated, and the defects such as the deterioration of the image quality do not occur. In the above description, an example of the driving roller 1 is described as the fixing roller 1a of the fixing roller pair of the fixing device. However, when the pressure roller 1b of the fixing device is used as a driving roller, an image sheet or the like is used. The same applies to the case where it is used as a conveyance driving roller used for conveyance. Therefore, description of these other examples will be omitted.

[0011]

[Effect of device]

 Since the present invention is configured as described above, no distortion or bulge due to stress is generated between the circular portion and the non-circular portion of the drive roller or in the circular portion. Therefore, the shape is simple and the yield in mass production is high. It is now possible to provide an image forming apparatus that forms a high quality image by using a driving roller of good quality and high precision.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a plan view of a main part of an image forming apparatus showing an embodiment of the present invention.

FIG. 3 is a perspective view illustrating a main part of a conventional image forming apparatus.

FIG. 4 is a plan view for explaining a main part of a conventional image forming apparatus.

[Explanation of symbols]

1 ... drive roller, 1a ... fixing roller, 1b ...
・ Pressure roller, 2 ... Circular part, 3 ... Non-circular part, 4
... Notch portion, 4a ... Notch hole, 5 ... Rotational driving force transmitting means, 6 ... Image sheet, 7 ... Nip portion, 8 ... Heater, 101 ... Driving Roller, 10
1a: fixing roller, 101b: pressure roller, 1
02 ... circular part, 103 ... non-circular part, 105 ...
.Rotational driving force transmitting element, 106 ... image sheet, 10
7 ... Nip part, 108 ... Heater.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Sotohiro Tsujihara 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Innovator Yasuhiro Kodaira 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh

Claims (2)

[Scope of utility model registration request] 1. An image forming apparatus having a mechanism for conveying an image sheet or the like by driving a driving roller, wherein the driving roller has a circular portion at a central portion in the axial direction and has a non-circular shape at least at one end in the axial direction. A portion, further having a notch portion between the circular portion and the non-circular portion,
An image forming apparatus, which conveys and drives an image sheet or the like by engaging a non-circular portion of the drive roller with a rotational drive force transmission means to transmit the rotational drive force to the drive roller. 2. The image forming apparatus according to claim 1, wherein the cutout portion is a cutout hole.