JP3095204U - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus having a duplex printing function for simplifying the shape of a paper path, shortening the time required for duplex printing, and processing a jam generated in the paper path. The structure of the jam handling mechanism is simplified. SOLUTION: A sheet is sequentially fed in a paper passing path R1 from a sheet feeding section 61 of a sheet tray 60 through an image forming area 10 to a switchback area 20, an image is formed on the surface of the sheet, and the sheet is switched back. By reverse feeding from the area 20, the image forming area 10 is turned upside down and passed therethrough to form an image on the back surface of the sheet. The paper return path R <b> 2 of the paper reversely fed from the switchback area 20 reaches the paper feeding unit 61 via the inside of the paper tray 20. In the switchback area 20, the paper discharge path R3
Is continuous.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

  The present invention is directed to an image forming apparatus, in particular, without ejecting paper fed from a paper tray. , Equipped with a so-called double-sided printing function that can form images on both the front and back sides Image forming apparatus.

[0002]

[Prior art]

  In this type of image forming apparatus, as illustrated in FIG. 4, a device having an image forming area is used. A paper tray 2 is provided below the storage body 1 and is fed from the paper tray 2. The fed paper P is sequentially fed to the image forming area 3 and introduced, so that the paper P An image is formed on the surface. Further, the paper P on the surface of which the image is formed is After being sent from the area 3 to the switchback area 4, the switchback area 4 Is reversely fed from the back side and introduced into the image forming area 3 in an inverted state. An image is formed on the surface.

[0003]   In the image forming apparatus having such a double-sided printing function, the switchback area is conventionally used. The paper return path 5 for the paper sheet fed back from the area 4 is provided between the apparatus body 1 and the paper tray 2. It is known that a space S formed is used to form the space. It was also known to attach / detach another paper tray to / from the sheet S (for example, patent Reference 1). It is also known to form the above-mentioned paper return path inside the apparatus main body. (See, for example, Patent Document 2). In FIG. 4, 3a is a photoconductor and 3b is a photoconductor. Is a fixing unit, 6a is an optical unit, and 7a is a paper discharge unit.

[0004]

[Patent Document 1]   JP-A-5-61288

[Patent Document 2]   JP-A-5-72848

[0005]

[Problems to be solved by the device]

  However, as is the case with the conventional method, the paper fed backward from the switchback area will pass through. The paper return path is formed using the space formed between the main unit and the paper tray. Paper or if it is formed inside the machine, it will not come out of the paper tray. The starting portion 7a of the sheet passing path 7 for the fed sheet and the sheet passing path 5 described above are formed as separate paths. Since it is unavoidable, not only does the paper path required for double-sided printing become complicated, , The paper path becomes longer by the length of the beginning 7a of the paper path 7 and double-sided printing is required. There was a problem that it took a long time to do.

[0006]   Also, since the paper path has a complicated shape, the paper jam caused in the paper path is also accompanied. The problem that the structure of the jam handling mechanism for handling mari (jam) becomes complicated was there.

[0007]   The present invention has been made in view of the above problems, and the paper feed inside the paper tray is recovered. Paper fed from the paper tray and fed in sequence by using it as a path And the same paper that has been introduced into the paper tray via the paper return path. To be fed to the image forming area via a path, thereby simplifying the shape of the paper path. And the time required for double-sided printing is shortened, and at the same time, jams that occur in the paper path An image forming apparatus that facilitates simplification of the structure of the jam processing mechanism for processing The purpose is to serve.

[0008]

[Means for Solving the Problems]

  The image forming apparatus according to the present invention forms an image on a sheet from the sheet feeding unit of the sheet tray. Paper is forwarded in the paper passing path from the image forming area to the switchback area. Feed and form an image on the paper, then feed the paper back from the switchback area To turn the image forming area over so that the image is formed on the sheet. In the image forming apparatus, the reverse feed is performed from the switchback area. The paper return path of the ejected paper reaches the paper feeding section through the inside of the paper tray. , Is.

[0009]   As in this invention, the return path for the paper fed backward from the switchback area is used. If the paper reaches the paper feeding section through the inside of the paper tray, the paper is fed from the paper tray. The beginning of the paper feed path that reaches the switchback area of the fed paper is fed forward from the paper feeding unit. Of the paper that is fed in the reverse direction from the paper feeding path and the paper feeding section. Since it is also used as the pass path, the shape of the paper path required for double-sided printing is simplified. In addition, the paper path is shortened, and the time required for double-sided printing can be shortened. At the same time, the structure of the jam handling mechanism for handling jams generated in the paper path is also simplified. It becomes easy to base.

[0010]   According to the present invention, the paper sheet provided below the main body of the apparatus having the image forming area. Contact the topmost paper stored in the paper tray in the paper feeding section of the tray. The paper feeding roller is attached to the main body of the device, and the topmost paper is By the rotation of the paper feeding roller, the paper is fed from the paper feeding unit and The paper is fed to the image forming area through the paper forward path, and If the paper passing through the paper return path is moved to the paper feeding section by the rotation of the paper feeding roller. In this case, the configuration is adopted in which the paper is introduced by being reversely fed to the above paper feeding forward path. It is possible to According to this, the paper feeding roller moves the paper from the paper tray. Used not only to feed and feed paper in reverse, but also to feed paper in reverse. Therefore, the paper feeding roller for forward feeding and the paper feeding roller for backward feeding are separated. There is no need to install them individually. Also, form a paper return path between the main unit and the paper tray. Since it is not necessary to secure a space for the image formation, It becomes easy to plan.

[0011]   In the present invention, the paper feeding section of the paper tray is accommodated in the paper tray. There is a paper separation claw that covers the leading edge of the topmost paper that is The leading edge of the paper, which has been introduced into the paper tray through the paper return path, is fed out. The uppermost sheet is pulled until it is drawn into the rollers and is fed from the sheet feeding section. It is desirable to have a function to prevent the feeding of the. According to this, The paper that has passed through will be fed with the topmost paper stored in the paper tray. The situation of going down does not occur.

[0012]   Further, according to the present invention, a paper feed path extending from the paper feeding section through the image forming area is provided. The end of the path is the same as the beginning of the paper return path formed by the reverse feed path. Formed as an area, and that area is used as the switchback area. Along the paper return path that slopes downward at a point near the check area. The above-mentioned paper feed forwards that are inclined upward in the shape intersect, and those paper feed return paths The paper is fed back from the switchback area at the intersection of The paper that has been introduced into the paper path is prevented from entering the paper path and the paper is fed from the paper path. A structure in which fixed claw pieces that allow the paper to enter the paper return path are provided It is desirable to adopt. According to this, from the switchback area to the paper return path In some cases, reversely fed paper may enter the paper feeding path and cause a jam. The above-mentioned fixed claw pieces, which are weakened and do not move, exert such an action. This simplifies the configuration and makes it easier to control movable claw pieces. It has the advantage of not requiring control.

[0013]   The image forming apparatus according to the present invention is more concrete by adopting the following configuration. Be converted. That is, to form an image on the paper from the paper feeding unit of the paper tray. The paper is fed in the paper passing path from the image forming area to the switchback area. Image on a sheet of paper and feed the paper backward from the switchback area. The image forming area is turned over so that the image is formed on the paper. In the image forming apparatus, the image forming area is provided below the main body of the apparatus. The uppermost part stored in the paper tray in the paper feeding section of the above-mentioned paper tray A sheet feeding roller that comes into contact with the sheet of The uppermost sheet is fed from the above-mentioned sheet feeding section by the rotation of the sheet feeding roller. And is fed to the image forming area through the paper passing path. , The paper return path of the paper fed back from the switchback area is the paper tray Paper that reaches the paper feeding section through the inside of the By rotating the paper feeding roller, the paper is fed backward from the paper feeding unit to the paper feeding path. In addition, the paper tray is placed in the paper feeding section of the above-mentioned paper tray. There is a paper separation claw that covers the tip of the top paper stored in the lei, The paper separating claw is a paper that has been introduced into the paper tray through the paper return path. Until the leading edge of the paper is drawn into the paper feeding roller and fed from the paper feeding section. With the function to prevent the feeding of the uppermost sheet, the end of the sheet feeding path and the above The beginning of the paper return path is formed as the same area, and that area is used for the above switchback. Area, and the above-mentioned paper passing that is inclined downward in the vicinity of the switchback area In the return path, the above-mentioned paper-forwarding path that is inclined forwardly along the paper-returning path intersects. In addition, at the intersection of the paper feed return path and the paper feed forward path, the above switchback The paper that is fed back from the area and introduced to the paper return path is prevented from entering the paper path. A fixed claw piece that stops and allows the paper to enter from the paper passing path to the paper passing path. It is deployed and the paper is fed forward to the switchback area. By adopting a configuration in which the paper discharge paths that extend in the So embodied.

[0014]

[Embodiment of device]

  FIG. 1 is an explanatory view showing an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is I of FIG. FIG. 3 is an enlarged view of section I, and FIG. 3 is an enlarged view of section III in FIG.   The image forming apparatus shown in FIG. 1 includes a toner cartridge 12 having a photoconductor 11 and a fixing device. The image forming area 10, which is an area where 13 and the like are arranged, and the paper is switched back. The switchback area 20, the optical unit 30, and the sheet feeding roll, which are areas for storing Device 40, which has a power supply unit 50, and the like. It is equipped with a paper tray 60 to be removed.

[0015]   In this image forming apparatus, the paper feeding unit 61, which is the front end of the paper tray 60, is used. The paper fed from the paper is placed in the image forming area 10 for forming an image on the paper. It is fed in sequence and passes through the image forming area 10 so that it is necessary to form an image. An image is formed on the surface of the paper by performing processing such as transfer and fixing. And the surface The paper on which the image is formed is then transferred from the image forming area 10 to the switchback area. 20 is sequentially fed and installed, and then is fed back from the switchback area 20 to An image is formed on the back surface by passing through the image forming area 10 in an upside down posture. Where to forward Rito is a feed sheet in which the leading edge of the paper fed from the paper tray 60 moves forward. The reverse feed is a feed state in which the trailing edge of the sheet advances in the forward direction.

[0016]   The paper feeding roller 40 attached to the main body of the apparatus is stored in the paper tray 60. Loaded on the uppermost sheet of paper under its own weight, or a weak spring The uppermost sheet is elastically contacted by the force of By doing so, only one of the uppermost sheets P is fed from the sheet feeding unit 61. . Further, as shown in an enlarged manner in FIG. 2, the paper feeding section 61 of the paper tray 60 has , A paper separating claw 62 for covering the leading edge corner of the uppermost paper P from above, When the sheet feeding roller 40 rotates and a feeding force is applied to the sheet P, at the first stage Means that the leading edge of the paper P covered by the paper separating claw 62 remains at that position. As it is, the paper P slightly warps and deforms against the elasticity of the paper P, and the warping deformation occurs. Due to the restoring force afterward, the leading edge of the paper P comes off the paper separating claw 62 and becomes one paper P. The injury comes to be fed out as shown by an arrow a, and the action of the sheet separating claw 62 as described above. This prevents double feeding of paper.

[0017]   In this image forming apparatus, the sheet passage R is provided with a sheet feeding section 61 of the sheet tray 60. From the image forming area 10 to the switchback area 20. Paper return path R from the switchback area 20 to the paper feeding section 61 of the paper tray 60 2, and when the paper is sequentially fed in the paper passing path R1, an image is formed on the surface of the paper. Then, when the sheet is reversely fed in the sheet passing path R1, an image is formed on the back surface of the sheet. . Further, the paper is always fed backward in the paper passing return path R2.

[0018]   The paper passing path R1 extends upward from the paper feeding unit 61 of the paper tray 6 and then It turns to the rear so as to pass the upper side of the feeding roller 40 and reaches the image forming area 10. Then, after exiting the image forming area 10, bend forward so as to face forward. The end thereof reaches the switchback area 20. On the other hand, the paper return path R 1 has its beginning located in the switchback area 20 and the switchback area 2 After inclining downward from 0, it turns downward and passes through the lower side of the paper passing path R1. It extends to the front, and its end passes through the inside of the paper tray 60 and reaches the paper feeding section 61. is doing. Then, a feed roller 71 is provided in the sheet passing path R1 as needed, The switchback area 20 is provided with a paper discharge roller 72 that is controlled to rotate in the normal and reverse directions. Feed rollers 73 and 74 are provided on the paper return path R2 as required. In addition, A paper detection sensor 21 is installed in the touchback area 20 to enable double-sided printing mode. In this case, the paper detection sensor 21 reverses the rotation direction of the paper discharge roller 72. The control signal for switching to the desired time can be obtained. In addition, the switch bar In the switch region 20, the switchback region 20 extends in the sheet forward direction. The paper discharge path R3 is continuous.

[0019]   In the image forming apparatus configured as described above, the paper feeding roller 40 The uppermost sheet P fed from the sheet feeding section 61 by the rotation is the paper feed path R1. When it is introduced into the image forming area 10 via the An image is formed on the surface of the sheet during the passage. In this way an image is formed on the surface After the sheet exits the image forming area 10, the sheet passes the sheet passing path R1 and reaches the sheet discharge roller 72. Therefore, it is introduced into the switchback area 20. The sheet feeding roller 40 After feeding, the rotation is stopped.

[0020]   In this case, when the single-sided printing mode is set, the switchback area 2 The paper introduced to 0 is sent to the paper discharge path R3 by the rotation of the paper discharge roller 72. Will be ejected.

[0021]   On the other hand, when the duplex printing mode is set, the switchback area Before the trailing edge of the sheet introduced to the sheet 20 passes through the sheet ejection roller 72, The reverse direction of the roller 72 is controlled, and the reverse direction of the discharge roller 72 causes the switchback area 2 The paper is fed backward from 0 and enters the inside of the paper tray 60 through the paper return path R2. It The paper P that has entered the inside of the paper tray 60 in this way is then Paper feeding in which the end r is in contact with the uppermost paper stored in the paper tray 60 The roller 40, or contact the top sheet and the sheet. The sheet feeding roller 40 is inserted into the sheet feeding roller 40. Then, on the paper P1 The timing when the trailing edge r abuts the paper feeding roller 40, or Match the timing when the paper and the paper feeding roller 40 are separated and entered. Then, the paper feeding roller 40 starts to rotate, and thereby the paper feeding backward path R1 is reversely fed. The fed paper P1 is fed again to the paper passing path R1 and passes through the image forming area 10. An image is formed on the back surface of the image while passing. Paper with the image formed on the back side in this way After that, P1 enters the switchback area 20 through the paper passing path R1 and further Then, it is sent to the paper discharge path R3.

[0022]   In this embodiment, the paper return path R2 passes through the inside of the paper tray 60. Therefore, the paper ejected from the switchback area 20 is fed backward to the image forming area 10. An extra space for forming a paper feed path for introduction is provided on the main unit and the paper tray. It is not necessary to secure a space with a. Therefore, lower the height of the image forming device. It is easy to make it compact. Also, if the paper that reaches the end of the paper return path R2 is The sheet is fed by the feeding roller 40 and introduced into the sheet feeding path R1. And the paper feed path R1 feeds the paper fed from the paper tray 60 and fed in sequence. Since it is the same path as the excess path, the length of the paper passage in the double-sided printing mode is The time required for double-sided printing is reduced accordingly.

[0023]   Here, the paper that has been fed back in the paper return path R2 enters the inside of the paper tray 60 and When the trailing edge r hits the paper feeding roller 40, the paper feeding roller 40 Rotation causes the paper to be fed backwards from the topmost paper stored in the paper tray 60. A double feed occurs in which the stacked paper P1 overlaps and is fed out from the paper feeding unit 61. It is possible. However, in this embodiment, the top corner of the topmost sheet is The sheet separating claw 62 is covered by the sheet separating claw 62. The uppermost sheet accommodated in the sheet is fed by a minute amount rotation of the sheet feeding roller 40. Since it has a function to prevent the paper P1 from being fed out, The leading end is drawn into the paper feeding roller 40 and fed from the paper feeding portion 61. Up to, even if the sheet feeding roller 40 rotates, the uppermost sheet is fed. However, this avoids double feeding of paper.

[0024]   Further, in this embodiment, the end portion of the sheet feeding forward path R1 and the beginning portion of the sheet feeding return path R2 are the same. 3 is formed as a region of the switchback region 20 of FIG. As shown in the figure, the return path is inclined downward in the vicinity of the switchback area 20. R2 intersects with the paper-feeding forward path R1 that is inclined forwardly along the paper-feeding return path R2. The fixing claw pieces 80 are provided at the intersections of the paper feed return path R2 and the paper feed forward path R1. Then, the fixed claw piece 80 slightly protrudes toward the sheet passing path R1 side. Like this Then, the paper is fed backward from the switchback area 20 and is fed back in the direction R as indicated by the arrow m. If the paper that has been introduced in 2 hangs down in the paper return path R1, The fixed claw piece 80 slides and is guided in the paper passing backward path R2 as indicated by an arrow n. for that reason, The sheet fed backward from the switchback area 20 enters the sheet passing path R1 and jams. Will not occur. On the other hand, an arrow h is drawn from the sheet feeding forward path R1 to the sheet feeding backward path R2. As described above, the sheet is guided by the fixed claw piece 80 to enter.

[0025]

[Effect of device]

  As described above, according to the present invention, the inside of the paper tray is used for the paper return path. Therefore, the passage path for the paper that is fed from the paper tray and fed in sequence, and the paper tray The paper path will be shared with the paper path that has been fed back inside the paper. . Therefore, it is easy to simplify the shape of the paper passage and the time required for double-sided printing. And the jam processing mechanism for processing jams generated in the paper passage. This has the effect of simplifying the manufacturing process.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a part II in FIG.

FIG. 3 is an enlarged view of a part III in FIG.

FIG. 4 is an explanatory diagram of a conventional example.

[Explanation of symbols]

10 image forming apparatus 20 Switchback area 40 Paper feeding roller 60 paper tray 61 Paper feeding section 62 Paper separation claw 80 Fixed claw piece R1 paper outbound route R2 paper return R3 paper ejection path

Claims (5)

[Scope of utility model registration request] 1. A sheet is fed in sequence through a sheet feeding path from a sheet feeding section of a sheet tray to an image forming area for forming an image on the sheet to a switchback area, and the image is formed on the sheet. An image forming apparatus configured to reversely pass through the switchback area to pass the image forming area over to form an image on the sheet, and the image forming apparatus is provided below the apparatus body having the image forming area. Further, a paper feeding roller that comes into contact with the uppermost paper stored in the paper tray in the paper feeding portion of the paper tray is attached to the apparatus main body, and the uppermost paper is rotated by the rotation of the paper feeding roller. The sheet is fed from the sheet feeding section, and is sequentially fed to the image forming area through the sheet passing path. The paper feeding backward path of the paper fed backward from the paper reaches the paper feeding section via the inside of the paper tray, and the paper passing through the paper feeding backward path is fed from the paper feeding section to the paper feeding section by the rotation of the paper feeding roller. It is designed such that it is fed back into the paper path and is introduced, and the paper feeding section of the above-mentioned paper tray is equipped with a paper separation claw that covers the leading end of the uppermost paper stored in the paper tray. The sheet separating claw prevents the uppermost sheet from being fed out until the leading edge of the sheet introduced into the sheet tray through the sheet return path is drawn into the sheet feeding roller and fed from the sheet feeding section. It has a function, and the end of the paper feed forward path and the start of the paper feed return path are formed as the same area, and the area is defined as the switchback area. At the place, the paper return path that is inclined downwards is intersected with the paper path that is inclined upwards along the paper return path.
At the intersection of the paper feed return path and the paper feed forward path, the paper fed back from the switchback area and introduced into the paper feed return path is prevented from entering the paper feed forward path, and A fixing claw piece that allows the paper to enter the paper return path is provided, and a discharge path that extends in the forward feeding direction of the paper in the switchback area is continuous in the switchback area. Image forming apparatus. 2. A paper sheet is fed in sequence on a paper feeding path from a paper feeding section of a paper tray to an image forming area for forming an image on the paper sheet and a switchback area to form an image on the paper sheet. In an image forming apparatus configured to form an image on a sheet of paper by reversing the image forming area by reversely feeding the sheet from the switchback area, a paper return path of the sheet reversely fed from the switchback area. The image forming apparatus is characterized in that the sheet reaches the sheet feeding section through the inside of the sheet tray. 3. A sheet feeding roller, which comes into contact with an uppermost sheet accommodated in the paper tray in a sheet feeding section of the sheet tray disposed below the apparatus body having the image forming area, The uppermost sheet is fed from the sheet feeding section by the rotation of the sheet feeding roller, and is sequentially fed to the image forming area through the sheet feeding forward path. 3. The image forming apparatus according to claim 2, wherein the sheet that has passed through the paper return path is fed back from the paper feeding section to the paper passing path and introduced by the rotation of the paper feeding roller. 4. A paper feeding part of the paper tray is provided with a paper separating claw for covering the leading end of the uppermost paper stored in the paper tray, and the paper separating claw passes through the paper feeding return path. The image according to claim 3, further comprising a function of preventing the topmost sheet from being fed until the leading edge of the sheet introduced into the sheet tray is drawn into a sheet feeding roller and fed from the sheet feeding section. Forming equipment. 5. An end portion of a sheet feeding forward path extending from the sheet feeding portion through an image forming area and a beginning portion of a sheet feeding backward path formed by the reverse feeding sheet feeding path are formed as the same area. The area is defined as the switchback area, and in the vicinity of the switchback area, the sheet return path that is inclined downward and forward is intersected with the sheet forward path that is inclined upward along the sheet return path. , At the intersections of the paper feed return path and the paper feed forward path, the paper fed back from the switchback area and introduced into the paper feed return path is prevented from entering the paper feed forward path, and The image forming apparatus according to any one of claims 2 to 4, further comprising a fixed claw piece that allows the sheet to enter from the sheet to the sheet return path.