JP4993681B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that executes an electrophotographic copying process, such as a copying machine, a printer, or a facsimile machine.

  In the image forming apparatus, there is known an apparatus equipped with a reversing unit having a function of discharging a printing surface downward so that double-sided printing or printed matter is arranged in the page order. The reversing unit in this type of image forming apparatus generally includes a reversing entrance path for transporting the recording material paper into the unit, a reversing path for reversing the paper, a reversing section for transporting the reversed paper, and after the reversing. A reversing exit path for discharging the sheet with the printing surface facing down is provided, and a double-sided conveying path for re-carrying the sheet to the image forming unit to form an image on the back side of the sheet after reversing.

  On the other hand, as a means for confirming paper (remaining paper) remaining in the main body of the apparatus due to a jam or the like, the remaining paper is detected by an electro-optical paper detection sensor which is arranged in the transport path and used for the paper transport operation. In general, the operator confirms the presence or absence, and the operator processes the remaining paper in accordance with the instructions on the display displayed on the operation unit.

  However, particularly when performing the remaining paper processing in a large apparatus such as a high-speed machine, it is easy to forget the invisible paper, and the number of remaining paper in the apparatus may increase. It will also hang. In particular, the reversing unit often has poor paper visibility and often takes time to process the remaining paper.

JP 2002-145534 A

  Therefore, in Patent Document 1, the upper guide plate in the pulled out reversing unit can be pivoted upward to be opened widely, and in this way, the remaining paper can be satisfactorily processed in a visible state. is there.

  However, there are many cases where the remaining sheet is left in a state straddling the image forming apparatus main body and the above reversing unit at the time of jamming. The so-called tearing of the paper that is damaged occurs. If tearing occurs and the broken pieces are fine, it may be difficult for the operator to process and the remaining paper processing may be very difficult. Furthermore, the tearing of high-rigidity paper such as cardboard has a problem that the unit itself may be damaged.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances, and it is an object of the present invention to provide an image forming apparatus that can easily process a remaining sheet and can reliably prevent tearing of a sheet caused by pulling out a reversing unit from the apparatus body. .

In order to solve the above problems, the present invention includes a reversing unit that is detachably attached to an image forming apparatus main body and that reverses a recording material on which an image is formed. In an image forming apparatus having a reversing entrance roller that leads to a reversing path, a reversing roller that can be rotated in the normal direction or reversing the recording material in the reversing path, and a reversing exit path through which the recording material reversed by the reversing roller passes. When a printing operation emergency stop occurs during reverse paper discharge printing using the reverse unit, when the reverse outlet detection means for detecting the presence or absence of the recording material arranged on the outlet side of the reverse outlet path detects the recording material, the nearest transport roller reversing outlet path of the forming apparatus main body, discharge a predetermined time or more required for the trailing end of the recording material from the reflected transference opening detection means detects the absence recording material that leaves the conveying rollers We propose an image forming apparatus characterized by driving direction.

In order to solve the above-described problems, the present invention includes a reversing unit that is removably attached to an image forming apparatus main body and reverses a recording material on which an image is formed, and the recording unit conveyed to the reversing unit. An image is formed by a reversing entrance roller that guides the material to the reversing path, a reversing roller that can be rotated forward or reverse to reverse the recording material in the reversing path, a reversing exit path through which the recording material reversed by the reversing roller passes. In an image forming apparatus having a double-sided conveyance path through which a recording material that forms an image passes on a non-printing surface, when an emergency stop of printing operation occurs during double-sided printing using the reversing unit, When the double-sided exit detection unit that detects the presence or absence of the recording material that has been placed detects the recording material, the double-sided exit detection unit detects the absence of the recording material for the conveyance roller that is closest to the double-sided conveyance path of the main body of the image forming apparatus. The trailing edge of the recording material from proposes an image forming apparatus, characterized in that to drive the re-feeding direction over a predetermined time required to exit the conveying roller.

  The present invention is effective when the reversing roller and the double-sided conveying roller provided in the reversing exit path and the double-sided conveying path of the unit are configured so that the rotation in the conveying direction via the recording material can be idled. is there.

  According to the present invention, even when a remaining sheet straddling the roller in the reversing unit and the roller on the apparatus main body occurs during an emergency stop due to a jam or the like, it is possible to prevent the remaining sheet from crying due to the drawer of the unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic vertical sectional view showing an example of an image forming apparatus according to the present invention. In the image forming apparatus shown here, an image forming unit 2 is arranged at the center of the image forming apparatus main body 1, and a paper feeding unit 3 is arranged below the image forming unit 2. A reading unit 4 for reading a document is disposed above the image forming unit 1, and a paper discharge storage unit 5 is provided on the left side of the image forming unit 1, and an image-formed sheet 30 is discharged and stored. The sheet 30 may be a sheet member made of a resin film other than paper.

  The image forming unit 2 includes a photoconductor 10 formed in a drum shape as an image carrier. Around the photoconductor 10 is a charging device 11 that performs charging processing on the surface, and laser light is applied to the surface of the image information. Are arranged, a developing device 13 for visualizing an electrostatic latent image formed by exposure on the surface, and a cleaning unit 14 for removing and collecting the toner remaining on the photoreceptor. In addition, the transfer device 15 that transfers the toner image formed on the photoconductor 10 to the paper 30, the toner on the paper from which the toner image was obtained passes between a pair of rollers, and heat and pressure are applied to form the toner image. Fixing devices 16 for fixing processing are respectively arranged.

  When image formation is started in such an image forming apparatus, the photoconductor 10 is rotated in the clockwise direction in the drawing, and at this time, the charging device 11 charges the surface of the photoconductor 10 to a predetermined polarity. Next, the charged surface is irradiated with laser light based on image information from the exposure device 12, whereby an electrostatic latent image is formed on the photoreceptor 10. The electrostatic latent image formed on the surface of the photoreceptor 10 is visualized as a toner image by the developing device 13, and the toner image is transferred onto the paper 30 by the transfer device 15.

  On the other hand, the paper feed unit 3 disposed below the image forming unit 2 is provided with a plurality of paper feed trays 31 on which, for example, different sizes and types of papers 30 are stacked. The uppermost paper 30 is fed toward the registration roller pair 17 by a paper feed unit having a pickup roller 32, a paper feed roller 33, and a reverse roller 34, and the front end of the registration roller pair 17 is stopped via an intermediate roller 23. It is hit by. Thus, after the paper 30 is aligned, the registration roller pair 17 resumes rotation at a timing such that the toner image formed on the photoconductor 10 matches the leading edge of the paper 30 at the transfer portion provided with the transfer device 15. Then, the sheet 30 is sent out toward the transfer unit.

  The reading unit 4 is provided with a document scanning device 41 known per se for reading as an image signal into a CCD or the like in order to read and scan a document placed on a contact glass (not shown). The image signal is digitized and image processed by an image processing unit (not shown). In the image forming unit 2, based on the image signal processed by the image processing unit, the light emitted from a laser diode LD (not shown) in the exposure apparatus 12 is irradiated to the photoconductor 10 through the optical system, and the surface is statically exposed. An electrostatic latent image is formed. An automatic document feeder 5 for automatically feeding a document is attached above the reading unit 4.

  The image forming apparatus according to the present embodiment, in addition to the function of a so-called digital copier that reads and digitizes a document and copies it onto a sheet as described above, allows image information on the document to be set as a remote location by a control unit (not shown). This is a multi-function image forming apparatus having a function of so-called printer that prints image information handled by a computer on paper and a function of a facsimile to be exchanged. The setting as the copying machine is performed by an operation unit (not shown) that can be arbitrarily set by the operator. In addition, all images formed by any function are discharged to the paper discharge storage unit 5.

  A reversing unit 100 is disposed between the image forming unit 2 and the paper feeding unit 3. Further, between the fixing device 16 and the paper discharge roller 18 that discharges the paper 30 to the paper discharge storage unit 5, the transport destination of the paper 30 that has been fixed is selectively selected as the paper discharge storage unit 5 or the reversing unit 100. A branch claw 20 for switching to is provided. When the branching claw 20 closes the path to the paper discharge storage unit 5 and opens the path to the reversing unit 100, the paper 30 is sent to the reversing unit 100 via the relay roller 21.

FIG. 2 is an explanatory view of a vertical section showing the reversing unit 100 of the present embodiment.
In FIG. 2, the reversing unit 100 has a reversing inlet path 101 for guiding the paper 30 to the reversing path 102, a reversing outlet path 103 for discharging the paper 30 reversed by the reversing path 102, and a paper 30 reversed by the reversing path 102. Each paper conveyance path of the double-sided conveyance path 104 through which the rear surface printing is performed is formed. The reversing entrance path 101 is provided with an entrance sensor 120 and a reversing entrance roller 110 having a single drive system for transporting the paper 30 to the reversing path 102. A possible reverse roller 111 is provided. Further, a reversing unit is provided at the exit of the reversing roller 111, and a reversing sensor 121, a reversing roller 112, and a switching claw 117 that switches the transport destination of the paper 30 from the reversing exit path 103 or the double-sided transport path 104 to the reversing section. Is provided. Furthermore, the reverse exit path 103 is provided with an exit sensor 122, and the double-sided conveyance path 104 is provided with double-sided conveyance rollers 113, 114, 115, 116 and a plurality of paper sensors 123, in this example, at appropriate intervals. 124, 125 are provided.

  In the reversing unit 100 configured as described above, when the paper 30 for discharging the back surface is sent to the paper discharge storage unit 5 via the branching claw 20 and the relay roller 21, the paper 30 is rotated by the rotation of the reverse entrance roller 110. It is conveyed from the reverse entrance path 101 to the reverse path 102. Based on the signal from the inlet sensor 120, the reverse roller 111 rotates in the paper entrance direction at the timing when the rear end of the paper 30 is nipped by the reverse roller 111 and completely passes through the reverse inlet roller 110. The paper is reversed by switching from normal rotation in the same direction as the roller 110 to reverse rotation. 2, the switching claw 117 closes the double-sided conveyance path 104 and opens the reverse exit path 103 as shown in FIG. Then, the sheet is discharged from the sheet discharge container 5 through the reverse exit roller 22. At this time, since the paper discharge storage unit 5 is reversed and discharged, the pages are arranged in page order.

  When the duplex printing mode is selected, when the sheet 30 is fed into the reversing unit 100 via the branching claw 20 and the relay roller 21, the reversing claw 117 is turned to the reversing exit path 103 as shown in FIG. Is closed and the double-sided conveyance path 104 is opened, so that it is conveyed to the double-sided conveyance path 104 by the reverse roller 112, passes through the double-sided conveyance rollers 113, 114, 115, and 116, and is discharged from the reverse unit 100. 23 is sent to the registration roller 17 through 23 to print the back surface.

  In the image forming apparatus configured as described above, in order to increase productivity, the paper 30 is transported in a state where the distance from the next paper is narrow, and if a paper jam occurs in any of the paper transport paths, the machine Emergency stop. That is, an emergency stop of the printing operation occurs. At this time, the sheet 30 can often be urgently stopped across the image forming apparatus main body and the reversing unit 100. Further, the reversing unit 100 is configured such that it can be pulled out in a direction perpendicular to the paper surface of FIG. 1 to perform jam processing and maintenance, and the paper 30 in a state straddling the image forming apparatus main body and the reversing unit 100 as described above. The removal of the reversing unit 100 is performed by pulling out the reversing unit 100. However, as described above, there is a problem that the paper breaks and tears apart.

  The location where the sheet 30 is left over the image forming apparatus main body and the reversing unit 100 is the first location straddling the relay roller 21 and the reversing entrance roller 110, straddling the reversing roller 112 and the reversing exit roller 22, or There are three places: a reversing roller 111, a second part straddling the reversing roller 112 and the reversing exit roller 22, and a third part straddling at least the most downstream double-sided conveying roller 116 and the intermediate roller 23 among the double-sided conveying rollers. In this case, the first place occurs in the reverse mode for reverse paper discharge and the double-side mode for double-sided printing, but the second part is only in the reverse mode and the third part is only in the double-side mode.

In the present invention, measures for preventing crying are taken for each of the above-described portions.
With respect to the remaining paper in the first location, the paper 30 is placed in the reversing path 102 so that the reversing unit 100 can be pulled out and the remaining paper can be removed without causing tearing. For this reason, when the inlet sensor 120 detects a sheet at the time of an emergency stop, the reverse roller is separated by a nip releasing means 130 for releasing the nip of the reverse roller 111 described later, and the reverse inlet roller 110 is driven to rotate. At this time, the reverse entrance roller 110 is driven until a predetermined time elapses after the entrance sensor 120 detects the absence of paper, so that the rear end of the paper 30 passes through the reverse entrance roller 110 and completely moves to the reverse path 102. To do. The relay roller 21 is configured to be able to be rotated with a one-way clutch in order to allow the sheet 30 to move at this time.

  With this configuration, even when the paper 30 is in the first position across the relay roller 21 and the reverse entrance roller 110 during an emergency stop, the paper moves to the reverse path 102 side and fits in the reverse unit 100. Even if the reversing unit 100 is pulled out, no tearing occurs.

  The nip releasing means 130 preferably releases not only the nip pressure but also completely separates the rollers. As an example of a specific configuration of the nip releasing means 130, as shown in FIG. 4, an operating link 133 that is pivotally supported by an operating lever 132 that rotates by excitation of a solenoid 131 is provided on the reverse roller 111. Lifts upward to release the nip. At this time, the roller moving upward is a driven roller of the reversing roller 111.

  With respect to the remaining paper in the first location, even if the reversing unit 100 is pulled out when the entrance sensor 120 detects that there is no paper, the paper will not cry, but a predetermined time after the entrance sensor 120 detects that there is no paper. If the reverse entrance roller 110 is driven until the time has elapsed, the rear end of the sheet 30 passes through the reverse entrance roller 110, so that the remaining paper processing can be performed very easily.

  Next, with respect to the remaining paper at the second location, the paper 30 is discharged out of the reversing unit 100 so that the reversing unit 100 can be pulled out and the remaining paper can be removed without causing tearing. For this reason, when the exit sensor 122 detects a sheet during an emergency stop, the reversing roller 111 is released by the nip releasing means 130, and the reversing exit roller 22 provided outside the reversing unit 100 is rotationally driven. At this time, the reversing roller 112 can be rotated with a one-way clutch, and the reversing exit roller 22 is driven until a predetermined time elapses after the exit sensor 122 detects the absence of the sheet. In this embodiment, the rear end is completely discharged from the reversing unit 100.

  With this configuration, even when the paper 30 is present at the second position straddling the reversing roller 112 and the reversing outlet roller 22 or straddling the reversing roller 111, the reversing roller 112 and the reversing outlet roller 22 at the time of an emergency stop, the paper Is discharged to the outside of the reversing unit 100, so that even if the reversing unit 100 is pulled out, no tearing occurs.

  Next, with respect to the remaining paper at the third location, the paper 30 is discharged out of the reversing unit 100, so that the reversing unit 100 can be pulled out and the remaining paper can be removed without causing tearing. For this reason, when the paper sensor 125 detects the paper during an emergency stop, the intermediate roller 23 provided outside the reversing unit 100 is driven to rotate. At this time, all of the duplex conveying rollers 113, 114, 115, 116 can be rotated by interposing a one-way clutch, and the intermediate roller 23 is driven until a predetermined time elapses after the paper sensor 125 detects the absence of paper. By doing so, the rear end of the paper 30 is completely discharged from the reversing unit 100.

  With this configuration, even when the paper 30 is present at least at the third position across the double-sided conveyance roller 116 and the intermediate roller 23 at the time of an emergency stop, the paper is discharged out of the reversing unit 100. Even crying does not occur.

Next, a procedure for taking out the paper 30 when it remains in the reversing unit 100 will be described.
2 and 3, the reversing unit 100 includes a reversing exit path 103, a reversing path 102, a reversing guide plate 200 that guides the sheet 30 on the upper side of the reversing exit path 103, and a lower side and both sides of the reversing path 102. Double-sided guide plates 210 and 220 for guiding the upper side of the conveyance path 104 are provided. As shown in FIG. 5, the reversing guide plate 200 is configured to be able to open upward with the fulcrum 201 as a fulcrum, and the double-sided guide plates 210 and 220 have the fulcrums 211 and 221 disposed after the reversing guide plate 200 is opened. As shown in FIG. 6, the fulcrum is configured to be openable upward like a double door.

  The double-sided guide plates 210 and 220 have a length in the transport direction that is substantially the same as the A4 horizontal length and the LT (letter) horizontal length, and can be opened upward with a double door opening as shown in FIG. Even if a small size such as a postcard size or the like is a remaining sheet near the fulcrums 211 and 221, for example, there is a concern that if the double-sided guide plates 210 and 220 are configured as one sheet, it will be difficult to access, but it is divided into two. Therefore, access by the operator is possible, and the remaining paper processing is possible.

  With this configuration, when there is paper (remaining paper) remaining in the reversing unit reversing unit 100 due to the occurrence of a jam or the like, the remaining paper processing by the operator is surely and easily performed. In the reversing unit 100, for example, when there is a remaining sheet straddling the reversing portion from the reversing path 102, the nip between the reversing roller 111 and the reversing roller 112 can be separated by opening the reversing guide plate 200 upward. The remaining paper is not restricted by the roller, and the processing is easy. In addition, since visibility is improved, accurate processing can be performed. Furthermore, since the nips of the double-sided conveyance rollers 113, 114, 115, and 116 can also be all released similarly for the double-sided guide plates 210 and 220, the remaining paper on the double-sided conveyance path 104 can be easily processed in the same manner as described above. Visibility is also good. 5 and 6, for the roller pair 111, 113, 114, 115.116 in which the nip is opened, the subscript a is attached to the roller located at the bottom in the state of FIG.

  By the way, if the double-sided guide plates 210 and 220 are configured as one sheet, there is a concern that if a small size sheet such as A5 size or postcard size is left in the vicinity of the fulcrum, the visibility is poor and access becomes difficult. In this embodiment, since the double-sided guide plates 210 and 220 are double-spread, the remaining paper processing by the operator can be easily performed.

  The double-sided guide plates 210 and 220 are made of, for example, a transparent resin or slit so that the presence or state of the remaining paper in the double-sided conveyance path 104 can be visually confirmed by opening the upper reversing guide plate 200 upward. It is effective to provide, and the remaining paper can be easily visually confirmed.

  It should be noted that the present invention is not limited to each of the above-described embodiments, and within the scope of the technical idea of the present invention, each of the above-described embodiments can be modified as appropriate in addition to those suggested in each of the above-described embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1 is a schematic vertical sectional view showing an example of an image forming apparatus according to the present invention. It is explanatory drawing of the vertical cross section which shows the inversion unit at the time of the inversion mode of this embodiment. It is explanatory drawing of the vertical cross section which shows the inversion unit at the time of the double-sided mode of this embodiment. It is a perspective view which shows an example of the nip cancellation | release means of this invention. It is explanatory drawing which shows the one aspect | mode which open | releases an inversion unit. It is explanatory drawing which shows the other aspect which open | releases an inversion unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Image forming part 30 Paper 100 Inversion unit 101 Inversion entrance path 102 Inversion path 103 Inversion exit path 104 Double-sided conveyance path 110 Inversion entrance roller 111 Inversion roller 112 Inversion roller 113-116 Double-sided conveyance roller 117 Switching claw 130 Nip releasing means

Claims (3)

Attached to the main body of the image forming apparatus so that it can be taken in and out,
A reversing unit for reversing the recording material on which the image is formed,
The reversing unit includes a reversing entrance roller that guides the conveyed recording material to a reversing path;
A reversing roller capable of normal rotation or reverse rotation that reverses the recording material in the reversing path;
In an image forming apparatus having a reversing exit path through which the recording material reversed by the reversing roller passes.
When a printing operation emergency stop occurs during reverse paper discharge printing using the reverse unit,
When the reversing exit detection means for detecting the presence or absence of the recording material arranged on the exit side of the reversing exit path detects the recording material,
The conveyance roller closest to the reversing exit path of the image forming apparatus main body is discharged for a predetermined time or more required for the trailing edge of the recording material to pass through the conveying roller after the reversing exit detecting means detects the absence of the recording material. And an image forming apparatus. Attached to the main body of the image forming apparatus so that it can be taken in and out,
A reversing unit for reversing the recording material on which the image is formed,
The reversing unit includes a reversing entrance roller that guides the conveyed recording material to a reversing path;
A reversing roller capable of normal rotation or reverse rotation that reverses the recording material in the reversing path;
A reversing exit path through which the recording material reversed by the reversing roller passes;
In an image forming apparatus having a double-sided conveyance path through which a recording material for forming an image passes on a surface on which no image is formed,
When a printing operation emergency stop occurs during double-sided printing using the reversing unit,
When the double-sided exit detection means for detecting the presence or absence of the recording material arranged on the exit side of the double-sided conveyance path detects the recording material,
Refeed the conveyance roller closest to the duplex conveyance path of the image forming apparatus main body for a predetermined time or more required for the trailing edge of the recording material to pass through the conveyance roller after the double-sided exit detection means detects the absence of the recording material. An image forming apparatus that is driven in a direction.   3. The reversing roller and the double-sided conveying roller provided in the reversing exit path and the double-sided conveying path of the unit, respectively, are configured such that the rotation in the conveying direction via the recording material can be idled. The image forming apparatus described.

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