JP4297101B2 - Developer and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a developing device used for forming a visible image by attaching toner to an electrostatic latent image formed on the surface of a photosensitive drum in an image forming apparatus such as a copying machine, a printer, and a facsimile machine.

  In such a developing device, if the toner leaks from the replenishing chamber for replenishing the toner, the leaked toner scatters, causing a problem in the image forming process, and the leaked toner scatters when the developing device is replaced. It is desirable to keep the contained supply chamber as sealed as possible. However, in order to replenish toner from the replenishment chamber to the developing roller, an opening for setting the developing roller must be provided, and toner may leak from a gap formed between the set developing roller and the opening. .

Therefore, a seal member is provided for such a gap to prevent toner leakage. For example, Patent Document 1 describes that a sliding member made of Teflon (registered trademark) felt is used as a side seal of the developing roller. Further, in Patent Document 2, a raised first seal member is provided in a gap between both end surfaces of the developing roller and both side surfaces inside the developing device housing so as to contact or be close to both end surfaces. A felt-like second seal member is provided so as to cover the side of the member facing the image carrier, and the surface is smooth so as to block the gap between both end portions of the developing roller and both side surfaces outside the developing device housing. The point which provided the 3rd sealing member which has is described.
JP 2001-134080 A JP 2004-86074 A

  In the above-described prior art, a seal member is provided at the end in the longitudinal direction of the developing roller so that the toner does not leak from the gap between the developing roller and the opening, but it has entered between the developing roller and the supply roller. It is difficult to prevent the toner from entering and leaking between the seal member and the developing roller at the shaft support portion as the rollers rotate.

  4A and 4B are a schematic view (FIG. 5A) viewed from the axial direction and a schematic view viewed from above (FIG. 5B) regarding the shaft support portions of the developing roller 101 and the supply roller 102 in the conventional developing device. is there. The main body frame 100 of the developing device pivotally supports the developing roller 101 and the supply roller 102, and a side seal member 103 is disposed on the shaft support portion, and the side seal member 103 is disposed on the end surfaces of the developing roller 101 and the supply roller 102. The toner is prevented from leaking from the end portion in the longitudinal direction of the developing roller 101 by pressure contact. Although this sealing method does not apply a seal member to the outer peripheral surface of the developing roller 101, there is an advantage that the entire area in the longitudinal direction of the developing roller 101 can be used for developing an electrostatic latent image, but as shown in FIG. When the developing roller 101 and the supply roller 102 rotate, excess toner of the toner supplied from the supply roller 102 moves toward the shaft support portion as shown by an arrow A as shown in FIG. And the boundary portion B of the developing roller 101 and the supply roller 102. When the amount of the excess toner staying increases, the excess toner gradually enters between the side seal member 103 and the developing roller 101 due to the rotation of the supply roller. Gradually, the toner moves to the arrow C, and the excess toner finally leaks to the outside.

  In order to prevent such leakage of excess toner, it is conceivable that the development roller 101 and the side surface seal member 103 are further pressed to prevent excessive toner from entering. However, if the pressure contact is increased, the rotation of the development roller 101 is increased. Will be disturbed.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device that prevents excessive toner from entering between a developing roller and a side seal member and prevents excessive toner from leaking out, and an image forming apparatus including the developing device. It is.

A developing device according to the present invention includes a developing roller that transfers toner to a photosensitive drum on which an electrostatic latent image is formed, a supply roller that supplies toner while being in contact with the developing roller, the developing roller, A developing device provided with a shaft support portion of the supply roller and having a main body frame having a supply chamber for supplying toner therein , wherein the developing roller has an axial end portion and a side frame of the main body frame. A sponge side seal member that is in close contact with the axial end of the developing roller and prevents toner leakage is sandwiched between them, and the axial length of the supply roller is shorter than the length of the developing roller. The side seal member extends between the axial end of the supply roller and the side frame, and the axial end of the supply roller and the side seal member Is provided with a base made of sponge and a Teflon felt attached to the side surface of the base on the developing roller side, and the Teflon felt is formed of the developing roller. It adheres along an outer peripheral surface, It is characterized by the above-mentioned. Further, the Teflon felt is formed in a band shape, and the upper part extends to a position higher than the outer peripheral surface of the supply roller, and the blade that is provided below the main body frame is in contact with the upper surface. And Further, the developing roller is characterized in that the pressure contact surface at the end in the axial direction is subjected to Teflon processing.

  By having the above-described configuration, an auxiliary seal member provided between the axial end portion of the supply roller and the side surface seal member and including a sliding contact sheet that is in sliding contact with the outer peripheral surface of the developing roller is provided. Therefore, the excess toner staying between the developing roller and the supply roller may be blocked by the auxiliary seal member and leak from between the developing roller and the side seal member before reaching the end portion in the axial direction of the developing roller. Is prevented.

  Further, the auxiliary seal member is composed of a sponge body having a belt-like Teflon felt attached as a sliding contact sheet body, so that the belt-like Teflon felt is brought into close contact with the outer peripheral surface of the developing roller, and the excess toner is developed. It can be reliably prevented from moving to the axial end of the roller. In addition, since the auxiliary seal member is made of a sponge body, the Teflon felt comes into pressure contact with the developing roller with flexibility, and can exert a sealing effect without affecting the rotating operation of the developing roller. It becomes possible.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a schematic sectional view of an entire image forming apparatus including an embodiment according to the present invention. The image forming apparatus 1 includes a recording unit 2 and a paper feeding unit 3.

  In the paper feed unit 3, paper feed cassettes 10a and 10b are arranged in two upper and lower stages, and a plurality of sheets of a predetermined size are stacked on a flapper 11a in the paper feed cassette 10a. A pickup roller 12a is disposed at the right end portion of the paper feed cassette 10a, and is urged upward by a spring member (not shown) so that the upper surface of the paper on which the flapper 11a is stacked is pressed against the pickup roller 12a. . When the pickup roller 12a is rotationally driven in this state, the sheets are fed one by one to the sheet conveyance path by the frictional force. In the paper feed cassette 10b as well, the paper loaded on the flapper 11b is fed by the pickup roller 12b in the same manner as the paper feed cassette 10a.

  The fed paper is first conveyed to the recording unit 2 by the feed roller 13 and the press roller 14. The conveyed sheet is nipped between the registration roller 15 and the press roller 16 and conveyed at a constant conveyance speed. The recording unit 2 includes a developing device 15, a memory removal brush 16, a charging roller 17, a photosensitive drum 18, a transfer roller 19, an exposure head 20, and a fixing roller 21 for recording on paper.

  When recording on paper, the surface of the photosensitive drum 18 is uniformly charged by the charging roller 17, and the charged surface of the photosensitive drum 18 is exposed by the exposure head 20 in accordance with the image recording signal. An electrostatic latent image is formed. Next, toner is supplied to the surface of the photosensitive drum 18 by the developing unit 15 to be transferred to an electrostatic latent image to be visualized, and the toner image visualized by the transfer roller 19 is transferred to a sheet. The transferred toner image is heated and pressed by the fixing roller 21 and the press roller 22 and fixed on the paper.

  In this way, a series of processes such as charging, exposure, development, transfer, and fixing to the photosensitive drum 18 are performed to perform image forming processing. The toner remaining on the surface of the photosensitive drum 18 after the transfer is weakened by the memory removing brush 16 and dispersed on the surface of the photosensitive drum 18 to be collected by the developing unit 15.

  In the developing device 15, an opening is formed on the photosensitive drum 18 side of the main body frame 30, and a developing roller 31 is pivotally supported. A supply roller 32 is pivotally supported adjacent to the developing roller 31, and a supply chamber 33 communicates with the supply roller 32. Toner is stored in the replenishing chamber 33, and the toner is agitated by the agitating member 34 provided in the replenishing chamber 33. At the upper part of the replenishing chamber 33, a lid body 35 is tightly fixed to the main body frame 30.

  The toner stirred in the replenishing chamber 33 is transferred toward the supply roller 32 and conveyed toward the developing roller 31 by the rotation of the supply roller 32. The toner transferred from the supply roller 32 to the developing roller 31 is leveled to a predetermined layer thickness on the surface of the developing roller 31 by a blade (not shown) and is supplied to the photosensitive drum 18.

  The paper fixed by the fixing roller is nipped between the paper discharge roller 23 and the press roller 24 and carried out. Also, a manual paper feed mechanism is provided on the side surface of the apparatus main body, and the paper inserted into the paper feed port is sandwiched between the feed roller 25 and the press roller 26 and carried into the apparatus. 15 and the press roller 16 to perform the same image forming process as described above.

  2 is a partially enlarged cross-sectional view of a shaft support portion of the developing roller 31 and the supply roller 32 cut along a plane along the rotation axis, and FIG. 3 is a cross-sectional view taken along the line AA in FIG. These are BB sectional drawing in FIG.

  As shown in FIG. 2, shaft holes 30 a and 30 b in which the rotating shaft 31 a of the developing roller 31 and the rotating shaft 32 a of the supply roller 32 are supported are formed in the side frame that is a shaft supporting portion of the main body frame 30. ing. A side seal member 36 made of sponge is sandwiched between the axial end portion 31 b of the developing roller 31 and the side frame of the main body frame 30. The rotating shaft 31a passes through the side seal member 36 and is pivotally supported by the side frame. Note that the pressure contact surface of the axial end portion 31b of the developing roller 31 may be subjected to Teflon processing in order to improve slidability.

  The length of the supply roller 32 in the axial direction is set to be shorter than the length of the developing roller 31. A side seal member 36 extends between the axial end 32b of the supply roller 32 and the side frame of the main body frame 30, and between the side seal member 36 and the axial end 32b. An auxiliary seal member 37 is provided. The auxiliary seal member 37 includes a base portion 37a having a predetermined thickness and made of sponge, and a belt-like Teflon felt 37b attached to the side surface of the base portion 37a on the developing roller 31 side.

  As shown in FIGS. 3 and 4, the base 37 a of the auxiliary seal member 37 has the rotation shaft 32 a of the supply roller 32 passing therethrough and the outer periphery thereof is fitted into the side frame of the main body frame 30. A belt-shaped Teflon felt 37b is attached to the outer periphery of the developing roller 31 side and the inner bottom surface side of the main body frame 30. The Teflon felt 37 b is in close contact with the outer peripheral surface of the developing roller 31, and its upper portion extends to a position higher than the outer peripheral surface of the supply roller 32. A blade 38 provided below the main body frame 30 is in contact with the upper surface. In this way, since the upper surface of the Teflon felt 37b is pressed by the blade 38 and the lower part is pressed against the main body frame 30, it is not peeled off and rolled up with the rotation of the developing roller 31.

  When the developing roller 31 and the supply roller 32 rotate, the excess toner moves in the direction of the arrow A as in the conventional technique shown in FIG. 5 (see FIG. 2). The surplus toner that moves in the direction of arrow A is blocked by the Teflon felt 37b and moves in the direction of arrow B before reaching the axial end 31b of the developing roller 31. Therefore, excess toner can be prevented from leaking from between the developing roller 31 and the side seal member 36.

  Further, since the Teflon felt 37b is adhered to the sponge base 37a, the Teflon felt 37b comes into pressure contact with the surface of the developing roller 31 in a flexible state and does not affect the rotation of the developing roller 31.

1 is a schematic sectional view of an entire image forming apparatus according to an embodiment of the present invention. It is the partially expanded sectional view which cut | disconnected the axial support part of the developing roller and the supply roller by the surface along a rotating shaft. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a partially expanded sectional view regarding the axial support part of the conventional developing roller and supply roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Recording part 3 Paper feeding part
15 Developer
30 Body frame
31 Developing roller
32 Supply roller
36 Side seal member
37 Auxiliary seal member
37a base
37b Teflon felt
38 blades

Claims (3)

A developing roller that transfers toner to the photosensitive drum on which the electrostatic latent image is formed, a supply roller that supplies toner while being in contact with the developing roller, and a shaft support portion of the developing roller and the supply roller are provided. And a main body frame having a replenishing chamber for replenishing toner therein , wherein a shaft of the developing roller is provided between an axial end of the developing roller and a side frame of the main body frame. A side seal member made of sponge that is in close contact with the direction end portion to prevent toner leakage is sandwiched, and the axial length of the supply roller is set to be shorter than the length of the developing roller. The side seal member extends between a direction end and the side frame, and an auxiliary seal member is provided between the axial end of the supply roller and the side seal member. Vignetting and,
The auxiliary seal member includes a base made of sponge and a Teflon felt adhered to a side surface of the base on the developing roller side, and the Teflon felt is in close contact with the outer peripheral surface of the developing roller. Characteristic developing device. The Teflon felt is formed in a band shape, and an upper part extends to a position higher than the outer peripheral surface of the supply roller, and a blade provided below the main body frame is in contact with the upper surface. The developing device according to claim 1. 3. The developing device according to claim 1, wherein the developing roller has Teflon processing applied to a pressure contact surface at an end portion in an axial direction.

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