JP5538284B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Japanese Patent Application Laid-Open No. 2005-228561 discloses a transport mechanism that transports residual toner removed from a photosensitive drum to a waste toner box in an electrophotographic image forming apparatus. The transport mechanism includes a transfer spiral for transporting residual toner removed from the photoconductive drum in the axial direction of the photoconductive drum, a transport path for dropping the toner transported by the transport spiral downward, and receiving from the transport path. And a transporting coil for transporting the waste toner in a direction perpendicular to the axis of the photosensitive drum and supplying the waste toner box. In this transport mechanism, a transfer spiral that is relatively close to the photosensitive drum is driven by a driving device provided in the photosensitive unit, while a transport coil that is relatively far from the photosensitive drum is provided on the main body side of the image forming apparatus. It is driven by the driven device.

JP 2004-361564 A

  By the way, in the said prior art, since a transfer spiral and a coil for conveyance are driven by a separate drive device, the number of parts increases and the price increases. In the above prior art, since the transfer spiral and the transfer coil are relatively separated from each other, it is difficult to reduce the size of the image forming apparatus.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to realize price reduction and size reduction.

  In order to achieve the above object, according to the present invention, as a first solution, an image forming apparatus that removes residual toner from an image carrier, which is a cylindrical rotating body, with a predetermined removing means and collects it in a waste toner box. A first screw transport unit that is provided along the axial direction of the image carrier and that transports residual toner received from the removing means in the axial direction of the image carrier; and the axial direction of the image carrier. Are provided along different directions, and a second screw transport unit that transports residual toner received from the first screw transport unit in a direction different from the axial direction of the image carrier and supplies it to the waste toner box A first transmission means for transmitting the rotational force of the image carrier to the first screw transport section; and a second transmission means for transmitting the rotational force of the image carrier to the second screw transport section. And To Bei, to adopt the means of.

  In the present invention, as the second solution means, in the first solution means, the first transmission means is provided on one end side of the image carrier, and the second transmission means is the other of the image carrier. The means of being provided on the end side is adopted.

  In the present invention, as a third solving means, in the first or the second solving means, there is further provided an exciting means for applying vibration to a connection portion between the first screw conveying portion and the second screw conveying portion. The means of having is adopted.

  In the present invention, as the fourth solving means, in the third solving means, the vibration means constitutes an urging means for urging the image carrier to one end side and the second transmitting means. A pair of gears provided opposite to each other at the other end of the image carrier, each having a different number of teeth and having a cam surface having a step on one side and a protrusion abutting on the other cam surface. The method of consisting of is adopted.

According to the present invention, since the first screw conveyance unit and the second screw conveyance unit are driven using the rotational force of the image carrier, no separate driving device is required as in the prior art. The number of points is reduced, and a low price can be realized.
Further, according to the present invention, the first screw conveyance unit and the second screw conveyance unit are close to each other in order to use the rotational force of the image carrier, and are not separated from each other as in the prior art. It is possible to realize downsizing.
Further, according to the present invention, since the image carrier having high strength is used as a transmission shaft for transmitting the rotational force to the first screw conveyance unit and the second screw conveyance unit, the transmission shaft is not twisted or damaged. It is unlikely to occur.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus A according to an embodiment of the present invention. FIG. 2 is a perspective view showing a photoreceptor unit 21 and a waste toner box 22 in one embodiment of the present invention. 2 is a plan view showing an internal configuration of a photoreceptor unit 21 in an embodiment of the present invention. FIG. FIG. 4 is a perspective view (a) near one end of the photosensitive drum 211 and a perspective view (b) near the other end of the embodiment of the present invention. It is a perspective view which shows the structure of the cam 224 in one Embodiment of this invention. It is sectional drawing of the 2nd conveyance path 219b in one Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
An image forming apparatus A according to the present embodiment is a copying machine that forms an image on recording paper based on an electrophotographic method. As shown in FIG. 1, an image reading unit 1 that reads an image of a document, and an image data And an image forming unit 2 that forms an image on a recording sheet.

  The image reading unit 1 is a functional component that reads an image (original image) of a document placed on the platen glass with an image sensor and converts it into document image data, and outputs the document image data to the image forming unit 2. To do.

  As shown in FIG. 1, the image forming unit 2 includes a photoconductor unit 21, a waste toner box 22, an exposure unit 23, a development unit 24, a fixing roller 25, a paper feed cassette 26, a paper feed tray 27, a paper discharge tray 28, and the like. And is a functional component that forms (copies) a document image on recording paper based on the image data supplied from the image reading unit 1.

  1 to 3, the photosensitive unit 21 includes a photosensitive drum 211, a charging roller 212, a charging roller cleaning brush 213, a transfer roller 214, a cleaning blade 215, a first screw conveying unit 216, and a first drum gear. 217a, a second drum gear 217b, a third drum gear 217c, a first screw gear 218, a second screw transport unit 219, a connection gear 220, a rotation conversion gear 221, a second screw gear 222, and a biasing spring 223. Note that description of parts not directly related to the characteristics of the image forming apparatus A is omitted.

  The photosensitive drum 211 is a cylindrical rotating body having a peripheral surface formed of a predetermined photosensitive material and extending in the depth direction from the front of the image forming apparatus A. As shown in the drawing, a first drum gear 217a is coaxially arranged at one end. The second drum gear 217b and the third drum gear 217c are coaxially provided at the other end. The photosensitive drum 211 is rotationally driven when the first drum gear 217a meshes with a drive gear (not shown). Further, such a photosensitive drum 211 is an image carrier that carries a toner image based on an electrostatic latent image on its peripheral surface.

  The charging roller 212 is a cylindrical body disposed opposite to the photosensitive drum 211 and uniformly charges the peripheral surface of the photosensitive drum 211. The charging roller cleaning brush 213 is disposed so as to contact the peripheral surface of the charging roller 212 and cleans the peripheral surface of the charging roller 212.

The transfer roller 214 is disposed to face the photoconductive drum 211 and applies a transfer bias (high voltage) to the recording paper supplied from the paper feed cassette or the paper feed tray, thereby applying a transfer bias (high voltage) to the peripheral surface of the photoconductive drum 211. The toner image formed on the recording medium is transferred onto a recording sheet. The charging roller cleaning brush 213 and the transfer roller 214 rotate by obtaining a rotational force from the first drum gear 217a. The charging roller 212 rotates following the photosensitive drum 211 with which the peripheral surface abuts.
The cleaning blade 215 is a plate-like member whose tip is in contact with the peripheral surface of the photosensitive drum 211, and is a removing unit that scrapes off and removes toner (residual toner) remaining on the photosensitive drum 211 after transfer.

  The first screw conveyance unit 216 is provided along the axial direction of the photosensitive drum 211, and conveys residual toner received from the cleaning blade 215 in the axial direction of the photosensitive drum 211, and the first screw 216a. And a first transport path 216b. The first screw 216a is disposed along the axial direction of the photosensitive drum 211 in the first conveyance path 216b, and the first screw gear 218 is coaxially connected to one end.

  That is, the first screw 216a is rotated by the rotational force transmitted through the first screw gear 218, and the residual toner received by the first conveying path 216b from the cleaning blade 215 is aligned along the axial direction. The photosensitive drum 211 is conveyed in the other end direction (direction of the second screw conveying unit 219). The first transport path 216b is a transport path for residual toner transported by the first screw 216a, and is provided to cover the first screw 216a along the axial direction. At the other end of the first conveyance path 216b, an opening (not shown) for transferring residual toner to the second screw conveyance unit 219 is formed.

  The first drum gear 217 a is coaxially connected to one end of the photosensitive drum 211, and transmits the rotational force obtained from the drive gear (not shown) to the photosensitive drum 211. Further, the first drum gear 217a is engaged with a gear connected to the first screw gear 218, the charging roller cleaning brush 213, and the transfer roller 214, and transmits the rotational force. Note that the charging roller 212 abuts on the circumferential surface of the photosensitive drum 211 and obtains rotational force from the photosensitive drum 211.

  The second drum gear 217 b is coaxially provided at the other end of the photosensitive drum 211, meshed with the connection gear 220, and transmits the rotational force of the photosensitive drum 211 to the connection gear 220. The third drum gear 217c is coaxially provided at the other end of the photosensitive drum 211 in a state adjacent to the second drum gear 217b, and meshes with the connecting gear 220 in the same manner as the second drum gear 217b.

  Here, the second drum gear 217 b is a gear fixed to the photosensitive drum 211, but the third drum gear 217 c is provided to be rotatable with respect to the photosensitive drum 211. The second drum gear 217b and the third drum gear 217c are both meshed with the connecting gear 220 but have different fractional numbers. Therefore, the rotation speed of the second drum gear 217b and the rotation speed of the third drum gear 217c are mutually different. Different.

  As shown in FIG. 3, the connecting gear 220 is a gear that is provided so as to mesh with the second drum gear 217 b and the third drum gear 217 c and is provided coaxially with the rotation conversion gear 221. That is, the connecting gear 220 rotates by the rotational force transmitted from the photosensitive drum 211 via the second drum gear 217b, and transmits the rotational force to the third drum gear 217c to rotate the third drum gear 217c. .

  The first screw gear 218 is coaxially connected to the first screw 216a, and rotates the first screw 216a by meshing with the first drum gear 217a. As shown in FIG. 3, the second screw conveying unit 219 is provided in the vicinity of the other end of the photosensitive drum 211 along a direction orthogonal to the axis of the photosensitive drum 211. The second screw transport unit 219 supplies residual toner received from the first screw transport unit 216 to the waste toner box 22 by transporting the residual toner in a direction perpendicular to the axis of the photosensitive drum 211. 2 screws 219a and a second transport path 219b.

  The second screw 219a is disposed along the direction orthogonal to the axis of the photosensitive drum 211 in the second conveyance path 219b, and the second screw gear 222 is coaxially connected to one end. That is, the second screw 219a is rotated by the rotational force transmitted from the rotation conversion gear 221 via the second screw gear 222, and the second conveyance path 219b is received from the opening of the first conveyance path 216b. Residual toner is conveyed in a direction perpendicular to the axis of the photosensitive drum 211 and supplied to the waste toner box 22.

  The second conveyance path 219b is a conveyance path for residual toner conveyed by the second screw 219a, and is provided to cover the second screw 219a. One end of the second screw 219a is provided with a receiving port that communicates with an opening provided at the other end of the first conveying path 216b, while the other end is provided with a supply port (not shown) that communicates with the waste toner box 22. Abbreviation) is formed.

  The rotation conversion gear 221 is a worm having a rotation shaft common to the connection gear 220 and meshing with the second screw gear 222, and rotates by the rotational force transmitted to the connection gear 220 via the second drum gear 217b. The rotational force is converted in a direction perpendicular to the axis of the photosensitive drum 211 and transmitted to the second screw gear 222. That is, this rotation conversion gear 221 (worm) constitutes a worm gear together with the second screw gear 222 (worm wheel). Instead of such a worm gear, the rotation conversion gear 221 and the second screw gear 222 may be “helical gears” to convert the rotational force in the orthogonal direction.

  The biasing spring 223 is for biasing the photosensitive drum 211 in the other end direction, and is interposed between the photosensitive drum 211 and the first drum gear 217a.

  Here, as shown in FIG. 5, a cam 224 is formed on the opposing surface of the second drum gear 217b and the third drum gear 217c. The cam 224 is formed on one surface of the second drum gear 217b (the surface facing the third drum gear 217c), and the height in the direction facing the third drum gear 217c changes smoothly and at one position (step D). A cam surface 224a that changes abruptly and a projection 224b that is provided on one side of the third drum gear 217c (the surface facing the second drum gear 217b) and that has a tip abutting on the cam surface 224a.

  Such a cam 224 is formed on the opposing surface of the second drum gear 217b and the third drum gear 217c, and the photosensitive drum 211 is biased in the other end direction by the biasing spring 223, so that the projection 224b Is always in contact with the cam surface 224a. Further, since the rotation speeds of the second drum gear 217b and the third drum gear 217c are different, the contact portion of the protrusion 224b on the cam surface 224a is sequentially moved by the rotation of the photosensitive drum 211. As a result, the photosensitive drum 211 gradually moves in the one end direction as it rotates, and repeats the movement of suddenly returning in the other end direction at the moment when the protrusion 224b reaches the stepped portion D.

  Note that the biasing spring 223, the second drum gear 217b, the third drum gear 217c, and the second drum gear 217b and the third drum gear 217c, which generate such reciprocating motion in the axial direction of the photosensitive drum 211, are formed on opposing surfaces. The cam 224 constitutes a vibrating means.

  On the other hand, the waste toner box 22 is a container for accumulating residual toner supplied from the second screw conveyance unit 219. Based on the image data, the exposure unit 23 irradiates the charged surface of the photosensitive drum 211 with laser light in a scanning manner. By irradiating the peripheral surface of the photosensitive drum 211 with the laser beam, an electrostatic latent image corresponding to the image data (original image) is formed on the peripheral surface. The developing unit 24 develops the electrostatic latent image formed on the peripheral surface of the photosensitive drum 211 as a toner image by supplying toner to the peripheral surface of the photosensitive drum 211.

  The fixing roller 25 includes a pair of rollers, and fixes the toner image on the recording paper by applying heat and pressure to the toner image on the recording paper transferred from the photosensitive drum 211. The fixing roller 25 discharges the recording paper after the fixing process to the paper discharge tray 28. The paper feed cassette 26 is a container for storing a bundle of recording paper. The paper feed tray 27 is a storage unit that receives manually fed recording paper. The paper discharge tray 28 is a storage unit that receives the recording paper on which the image is formed supplied from the fixing roller 25.

  In the image forming apparatus A, document image data of a document image read by the image reading unit 1 is supplied to the image forming unit 2, and the image forming unit 2 copies the document image on a recording sheet based on the document image data. That is, the image forming unit 2 forms a toner image on the surface of the recording paper taken out from the paper feeding cassette 26 or the paper feeding tray 27 and supplied to the photosensitive unit 21, and the toner image on the recording paper is transferred to the fixing roller. After fixing at 25, the paper is discharged to the paper discharge tray 28.

  Here, in the photoconductor unit 21, a toner image is transferred from the photoconductor drum 211 onto the recording paper, and residual toner on the photoconductor drum 211 is scraped off by the cleaning blade 215 and removed from the photoconductor drum 211. It is accommodated in the first transport path 216b. The first screw 216a rotates to convey the residual toner in the first conveyance path 216b in the other end direction along the axis of the photosensitive drum 211, and is provided at the other end of the first conveyance path 216b. From the opened opening to the receiving port of the second transport path 219b. Then, the second screw 219a rotates to convey the residual toner received by the second conveyance path 219b from the first conveyance path 216b in a direction perpendicular to the axis of the photosensitive drum 211, and further the residual toner. The toner is supplied to the waste toner box 22 from a supply port provided at the other end of the second transport path 219b.

  In such a residual toner conveyance operation in the first screw conveyance unit 216 and the second screw conveyance unit 219, the first screw gear 218 transmits the rotational force from the first drum gear 217a to the first screw 216a. The second screw 219a rotates when the second screw gear 222 receives a rotational force via the second drum gear 217b, the connecting gear 220, and the rotation conversion gear 221. That is, the first screw transport unit 216 that transports residual toner in the axial direction of the photosensitive drum 211 and the second screw transport unit 219 that transports residual toner in a direction perpendicular to the axial line of the photoconductive drum 211 are both provided. The photosensitive drum 211 (cylindrical rotating body) is driven to rotate by obtaining power.

  Therefore, according to the present embodiment, since the first screw transport unit 216 and the second screw transport unit 219 do not require separate drive devices, it is possible to reduce the number of parts as compared with the prior art. Thus, a low price can be realized. In addition, the first screw conveyance unit 216 and the second screw conveyance unit 219 are close to each other in order to use the rotational force of the photosensitive drum 211, and are not separated from each other as in the conventional case. Therefore, downsizing can be realized. Further, since the photosensitive drum 211 having high strength is used as a transmission shaft that transmits the rotational force to the first screw conveyance unit 216 and the second screw conveyance unit 219, the transmission shaft is twisted or damaged. Very unlikely.

  Further, in the present image forming apparatus A, an oscillating means including a biasing spring 223, a second drum gear 217b, a third drum gear 217c, and a cam 224 formed on the opposing surface of the second drum gear 217b and the third drum gear 217c is provided. Therefore, the photosensitive drum 211 gently moves in one end direction and suddenly moves back in the other end direction, so that the connecting portion between the first screw conveying portion 216 and the second screw conveying portion 219 is repeated. That is, vibrations can be applied to the opening provided at the other end of the first transport path 216b and the vicinity of the receiving port of the second transport path 219b. This vibration removes the residual toner adhering to the connected portion, so that the residual toner can be reliably conveyed to the waste toner box 22.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the above embodiment, the second screw conveying unit 219 is arranged along the direction orthogonal to the axis of the photosensitive drum 211 and the residual toner is conveyed in the direction orthogonal to the axis, but the present invention is not limited to this. For example, the second screw conveyance unit 219 is not limited to the direction orthogonal to the axis, and may be provided in a direction different from the axial direction of the photosensitive drum 211 according to the position of the waste toner box 22.
(2) In the above embodiment, one step portion D is provided on the cam surface 224a, but the step portion D is not limited to one. A plurality of step portions D may be provided on the cam surface 224a at predetermined intervals.

  A ... Image forming apparatus, 21 ... Photosensitive unit, 22 ... Waste toner box, 23 ... Exposure unit, 24 ... Development unit, 25 ... Fixing roller, 26 ... Paper feed cassette, 27 ... Paper feed tray, 28 ... Paper discharge tray 211 ... photosensitive drum (image carrier), 212 ... charge roller, 213 ... charge roller cleaning brush, 214 ... transfer roller, 215 ... cleaning blade (removing means), 216 ... first screw conveying section, 216a ... first 1 screw, 216b... First conveying path, 217a... First drum gear, 217b... Second drum gear, 217c... Third drum gear, 218. Screw, 219b ... second conveying path, 220 ... connection gear, 221 ... rotation conversion gear, 222 ... second Clew gear, 223 ... urging spring, 224 ... cam, 224a ... cam surface, 224b ... projections

Claims (2)

An image forming apparatus that removes residual toner from an image carrier, which is a cylindrical rotating body, with a predetermined removing unit and collects it in a waste toner box,
A first screw conveyance unit that is provided along the axial direction of the image carrier and conveys residual toner received from the removing unit in the axial direction of the image carrier;
The residual toner is provided along a direction different from the axial direction of the image carrier, and the residual toner received from the first screw transport unit is transported in a direction different from the axial direction of the image carrier to the waste toner box. A second screw conveying section to supply;
First transmission means for transmitting the rotational force of the image carrier to the first screw conveyance unit;
Second transmission means for transmitting the rotational force of the image carrier to the second screw transport unit;
Further comprising a vibration means for applying vibration to a connection portion between the first screw conveyance unit and the second screw conveyance unit;
The excitation means constitutes an urging means for urging the image carrier to one end side and a second transmission means, and is provided opposite to the other end of the image carrier, and has the number of teeth. An image forming apparatus comprising: a pair of gears each having a cam surface which is different from each other and has a step on one side, and a projection which is in contact with the cam surface on the other side .   The image forming apparatus according to claim 1, wherein the first transmission unit is provided on one end side of the image carrier, and the second transmission unit is provided on the other end side of the image carrier.

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