JP3870866B2 - Paper transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet conveying device of an image forming apparatus, and more particularly, to a sheet conveying apparatus that can favorably convey a sheet in a sheet conveying path disposed between a sheet feeding unit and a recording unit.
[0002]
[Prior art]
In a small image forming apparatus, a recording paper creating means (recording unit) using an electrophotographic system is arranged between an image reading device provided at the upper part and a paper feeding unit arranged at the lower part, A discharge tray for discharging is provided on the side of the recording unit. In the small image forming apparatus, when an image reading apparatus is configured by combining an FBS (flatbed scanner) and an ADF (automatic document feeder), the image reading apparatus is a large size such as an A3 size. In many cases, the apparatus is configured as an apparatus capable of reading an image by placing a document of a size on a platen. Also, a paper feed tray arranged at the lower part of the apparatus main body can feed paper corresponding to the large-size document. Then, the paper fed from the paper feed tray is transported in a paper transport path configured in a substantially U shape toward the recording unit, and the toner image is transferred from the photosensitive drum in a state where the front and back of the paper are reversed. Is done. In the paper transport path for transporting the paper so as to be largely curved, the upper guide plate is disposed at a predetermined interval with respect to the main body guide of the apparatus main body in order to guide the paper at the horizontal portion above the curved portion. And a means for guiding the paper between the main body guide and the upper guide plate is used.
[0003]
[Problems to be solved by the invention]
However, in the paper conveyance path configured in the curved shape, in the portion where the upper guide plate is attached to the main body guide, when the main body guide is configured with a resin molded product and the upper guide plate is configured with a metal plate, It is inevitable that a gap is generated at the combined portion of the two members. In other words, when one of the two members is a resin product, the corners cannot be formed at right angles for mold removal after molding of the resin product, and a slight roundness is formed. In the connection portion of the guide plate of the paper conveyance path formed by combining the members, there is a problem that a gap is generated such that a corner portion of the paper enters. Therefore, when the paper conveyed in the paper conveyance path is skewed, the corner of the paper enters the gap between the connection portion of the upper guide plate and the main body guide, and a jam occurs. Prone to cause. When the jammed paper is removed, the corners of the paper that have entered the gaps on the side of the paper transport path are torn off, and a part of the jammed paper remains on the side of the paper transport path. There remains a problem that a sheet to be transported later is caught on the remaining piece of paper and easily causes a jam.
[0004]
The present invention is intended to solve the problem of jam occurring in the paper conveyance path, and a pin-shaped positioning member is slightly protruded toward the paper conveyance path at a portion connecting the upper guide plate and the main body guide. It is an object of the present invention to provide an apparatus that can provide a satisfactory guide action with respect to a corner of a skewed sheet.
[0005]
[Means for Solving the Problems]
In the present invention, an upper guide plate is provided on the main body guide of the apparatus main body by setting a predetermined interval, a paper transport path is formed between the main body guide and the upper guide plate, and the paper feeding unit to the recording unit. The present invention relates to a sheet conveying device of an image forming apparatus that conveys a sheet toward the sheet.
According to the first aspect of the present invention, a stepped portion for attaching the upper guide plate is provided on both side portions of the main body guide so as to protrude, and is overlapped on the end portion of the upper guide plate on the stepped portion and combined by a fixing means. In addition, a positioning member for positioning the upper guide plate on the main body guide is formed so as to protrude from the guide surface as a vertical surface inside the step portion toward the paper transport path, and transports the inside of the paper transport path. The side portion of the sheet to be printed is guided using the inner surface of the positioning member.
[0006]
According to a second aspect of the present invention, the positioning member is a pin member formed integrally with the step portion so as to protrude above the step portion, and the upper end portion of the pin member enters the hole of the upper guide plate. Thus, the upper guide plate is positioned on the main body guide.
According to a third aspect of the present invention, the sheet conveyance path is formed in a largely curved state, and the upper guide plate is disposed at a predetermined interval with respect to the main body guide at an upper portion of the curved portion. It is characterized by being.
[0007]
As described above, the positioning member is arranged in correspondence with the stepped portion, so that the skewed paper can be guided by the positioning member, and the corner portion of the paper enters the gap on the side of the paper conveyance path, and a jam occurs. Can be prevented. Further, by providing the side surface of the positioning member so as to protrude further toward the paper conveyance path side than the inner surface of the stepped portion, even if the positioning member protrudes from the inner side surface of the stepped portion, the paper conveyance Good guidance of paper on the road. By making the positioning member into a pin shape, the positioning member can be easily formed, and it is possible to satisfactorily guide the corner portion of the skewed paper.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the apparatus of the present invention will be described according to the illustrated example. The example shown in FIG. 1 describes the configuration of a small-sized image forming apparatus. An image reading device 3 is arranged on the upper part of the apparatus main body 2 provided with the recording unit 30 of the image forming apparatus 1. A large platen 15 corresponding to the FBS and a small platen 16 corresponding to the ADF 5 are disposed on the upper portion of the frame 10 of the image reading device 3. An opening / closing member 4 provided with a platen cover for pressing a document to be set on the large platen 15 is disposed on the upper portion of the frame 10 of the image reading device 3, and an ADF 5 is provided on one end of the upper portion of the opening / closing member 4. Yes. The ADF 5 configures a document conveyance path 7 between the document tray 6 and the document discharge tray 9 as a laterally U-shaped curved path, and a plurality of conveyance rollers for conveying the document in the document conveyance path. An apparatus 8 is provided, and an image of the conveyed document is read at the position of the small platen 16 below the document conveyance path.
[0009]
In the frame 10 of the image reading device 3, the reading device 11 is provided so as to be movable in the left-right direction in the drawing using a driving unit (not shown), and the reading device 11 is positioned at a solid line in the drawing. In the state of being stopped, the reading mode by the ADF 5 is set. Further, by moving the reading device 11 at a predetermined speed in the horizontal direction in the figure inside the frame 10, the image of the document set on the large platen 15 is read in the FBS mode. The reader 11 is provided with a combination of a full-rate carriage equipped with a lamp and one mirror and a half-rate carriage equipped with two mirrors so as to be movable like a commonly used device. it can. In addition, an apparatus that forms an image of reflected light from a document on a CCD by a lens disposed at a fixed position in the apparatus frame, converts the optical signal as a digital signal, and outputs read information to an image recording unit. It can also be configured as.
[0010]
In the illustrated example, the reading device 11 is provided with a lamp 12, a plurality of mirrors, a lens 13 and a CCD 14 combined in one moving frame. By configuring the reading device 11 as a single unit, the configuration of the driving mechanism for the reading device 11 can be simplified, and the image information of the read document is transferred to the main body of the device using a flexible signal cable. It can be transmitted to the control device. The optical path length of the plurality of mirrors provided in the reading device 11 can be formed by combining any number of mirrors, and the optical path length can be arbitrarily set as in the case of using two general carriages. The length can be set.
[0011]
A sheet feeding unit 20 is arranged at the lower part of the apparatus main body 2, and the sheet feeding unit 20 is equipped with one sheet feeding tray 21, but arranged so as to overlap two or many sheet feeding trays. Thus, it is possible to supply paper of an arbitrary size from each paper feed tray. The paper feed tray 21 disposed in the paper feed unit 20 raises the leading end of the paper placed on the bottom plate 23 toward the paper feed roller 24 with the rear end portion regulated by an end guide, and The paper taken out by the paper roller 24 is conveyed through the paper conveyance path 25. Conveying roller devices 26 and 27 are arranged in the paper conveying path 25 at a predetermined interval, and the toner image formed on the photosensitive drum 33 of the recording unit 30 is transferred onto the paper by the transfer roller 34.
[0012]
The recording unit 30 is provided with a combination of a developing device 31 for holding toner and a photosensitive unit provided with a photosensitive drum 33. Based on the image information obtained by the reading device, the writing unit 35 irradiates the photosensitive drum 33 with light to form an electrostatic latent image, and the developing device 31 is directed toward the electrostatic latent image. The toner is supplied from the developing roller 32 to form a toner image, and the toner image is transferred toward the paper by applying a predetermined potential from the transfer roller 34. The sheet on which the toner image has been transferred is fixed by applying heat and pressure through the fixing device 36, and the recording paper is discharged toward the discharge tray 38 by the discharge roller device 37. The discharge roller device 37 has been described as having a mechanism that conveys the recording paper while pressing the recording paper against the upper sliding plate using a single drive roller. Similarly to a typical discharge roller device, the drive roller and the pinch roller may be combined.
[0013]
A sheet conveying path 25 that conveys a sheet from the sheet feeding unit 20 toward the recording unit 30 is greatly curved between the conveying roller devices 26 and 27 as shown in an enlarged view in FIGS. It is formed in the state. In the upper part of the curved portion of the paper transport path 25, the upper guide plate 45 is disposed at a predetermined interval with respect to the main body guide 40, and the paper fed from the lower part in a curved state is placed on the upper side. Guide along the guide plate 45 and guide in the substantially horizontal conveyance path toward the recording unit. The main body guide 40 is made of a resin material as in the apparatus frame, and a step portion 42 that defines the side surface of the sheet conveyance path is provided at a portion where the upper guide plate 45 is attached, as shown in FIG. The guide surfaces 43 and 43 as the vertical surfaces inside the step portions 42 and 42 are formed wider than the width W of the sheet.
[0014]
In addition, the upper guide plate 45 is formed by punching a sheet metal, but may be formed using a resin material as long as it has sufficient strength. The upper guide plate 45 that defines the sheet conveyance path in combination with the main body guide 40 has a fixed portion 46, 46a that is mounted on the step portion 42. The end portion of the upper guide plate 45 is placed on the step portion 42 in a predetermined manner. In the state where only the range is overlapped, the fixing screw 47 is used to fix and attach.
[0015]
As shown in FIGS. 4 and 5, in the fixing portion 46 provided in the paper conveyance path 25, means for overlapping and fixing the upper guide plate 45 to the step portion 42 provided in the main body guide 40 is used. . By the way, in the fixing portion, if the upper guide plate 45 is simply overlaid on the stepped portion 42 provided on the side portion of the main body guide 40 and fixed with screws, it is inevitable that a gap occurs in the overlapping portion. There was a risk of paper entering the gap between the overlapping portions. Therefore, in this embodiment, the pin member 49 is provided so as to protrude integrally with the step portion 42 of the main body guide 40, and the lower portion of the pin member 49 is protruded to the sheet conveyance path side from the guide surface 43 of the step portion. Forming. That is, the pin member 49 has a pin-like shape protruding above the step portion 42, but the guide surface 43 serving as a vertical surface of the step portion 42 has a half portion of the diameter of the guide member 43. It is configured to project as an arc-shaped projection. The paper guide surface of the main body guide 40 is provided with a large number of ribs 41 protruding in a streak shape at a predetermined interval so that the guide action for the paper can be performed in a good state.
[0016]
Further, the fixing portion of the upper guide plate 45 is provided with a hole 48 into which the upper portion of the pin member 49 can be inserted at a position corresponding to the pin member 49 so that the upper guide plate 45 is placed on the step portion 42. When stacked, the pin member 49 is inserted into the hole 48 of the upper guide plate. When the corner of the skewed sheet hits the protrusion protruding from the guide surface of the step 42 defining the side of the sheet conveyance path, the corner of the sheet is a pin member. 49, a bending action is applied, but the corner portion of the paper is prevented from entering between the upper guide plate 45 and the stepped portion 42.
[0017]
Therefore, even if there is a slight gap between the upper guide plate of the sheet conveyance path 25 and the main body guide, the sheet conveyed while being skewed in the sheet conveyance path can enter the gap. Therefore, it is possible to reduce the occurrence of inconvenience such as paper jam. Further, in the fixing portion 46 of the upper guide plate 45, if the upper end portion of the pin member 49 can enter the hole 48 provided corresponding to the pin member 49, the upper guide plate 45 is moved to the main body guide 40. It is possible to position the sheet on the upper side of the sheet, and it is possible to prevent the corner portion of the sheet having the skew from entering the gap. Therefore, even if the corner portion of the sheet conveyed in the sheet conveyance path slides on the lower surface of the upper guide plate 45, the corner portion is curved when contacting the surface of the pin member 49. Since the sheet passes in the state, the corner portion of the sheet is prevented from entering the gap on the lower surface of the upper guide plate.
[0018]
In the fixing portion 46 of the upper guide plate 45, a guide member having another shape can be provided instead of the pin member for guiding the side surface of the sheet. For example, when a prismatic guide member is used, if the corner on the upstream side in the paper conveyance direction is formed in an arc shape, the guide action for the paper can be performed satisfactorily as in the case of the pin member. In addition, it is also possible to use an elliptical pin member member. Even when such guide means are provided, an insertion hole corresponding to the shape of the guide means is formed in the upper guide plate so that a gap is formed. What is necessary is just to be able to perform the operation of closing the upper guide plate and the positioning of the upper guide plate with respect to the main body guide.
[0019]
【The invention's effect】
In the apparatus of the present invention, as described above, the positioning member is arranged in correspondence with the stepped portion, so that the skewed paper can be guided by the positioning member, and the corner of the paper is inserted into the gap on the side of the paper transport path. Can prevent jamming from entering. Further, even if the positioning member is provided so as to protrude from the inner side surface of the step portion, it is possible to satisfactorily exhibit the paper guideability in the paper conveyance path. Furthermore, by using a pin-shaped positioning member, the positioning member can be easily formed, and the guiding action for the corners of the skewed paper can be satisfactorily performed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus.
FIG. 2 is an explanatory diagram showing an arrangement relationship of guide members in a paper transport path.
FIG. 3 is a plan view of a guide member corresponding to FIG. 2;
FIG. 4 is an enlarged explanatory view of a fixing portion in FIG. 3;
FIG. 5 is an explanatory diagram of a configuration of a side portion of a paper transport path.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 3 Image reading apparatus, 4 Opening-closing member,
5 ADF, 6 Document tray, 7 Document transport path,
8 transport roller device, 9 document discharge tray, 10 reading frame,
11 Reader, 14 CCD, 15.16 platen,
20 paper feed section, 21 paper feed tray, 22 end guide,
23 bottom plate, 24 paper feed roller, 25 paper transport path,
26/27 conveying roller device, 30 recording unit, 31 developing device,
32 developing roller, 33 photosensitive drum, 34 transfer roller,
35 writing means, 36 fixing device, 37 discharge roller device,
38 discharge tray, 40 body guide, 41 rib,
42 stepped portion, 43 guide surface (vertical surface), 45 upper guide plate,
46 fixing parts, 47 fixing screws, 48 holes, 49 pin members.

Claims (3)

On the main body guide of the apparatus main body, a predetermined interval is set to provide an upper guide plate, and a paper conveyance path is formed between the main body guide and the upper guide plate,
A sheet conveying device of an image forming apparatus that conveys a sheet from a sheet feeding unit toward a recording unit,
Steps for attaching the upper guide plate to both sides of the main body guide are provided so as to protrude, overlapped with the end of the upper guide plate on the stepped portion, and combined by fixing means,
A positioning member for positioning the upper guide plate on the main body guide is formed so as to protrude from the guide surface as a vertical surface on the inner side of the stepped portion toward the paper conveyance path,
A sheet conveying apparatus that guides a side portion of a sheet conveyed in the sheet conveying path using an inner surface of the positioning member. The positioning member is a pin member formed integrally with the stepped portion and protruding above the stepped portion,
The sheet conveying device according to claim 1, wherein the upper guide plate is positioned on the main body guide by the upper end portion of the pin member entering the hole of the upper guide plate.   The sheet conveying path is formed in a largely curved state, and the upper guide plate is disposed above the curved portion with a predetermined distance from the main body guide. Item 3. The paper conveying apparatus according to Item 1 or 2.

Images