JP3616517B2 - Image forming apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention adds an image forming apparatus such as a copying machine and a printer having a multiple image forming function such as double-sided transfer and composite image transfer, and the above-mentioned multiple image forming function to the image forming apparatus by mounting the image forming apparatus. The present invention relates to a paper circulation device for an image forming apparatus.
[0002]
[Prior art]
For example, as a method for realizing the double-sided copying function installed in the copying machine, for example, only one side of all the originals is copied together and stocked, and then the original is applied to the stocked paper. There are a method of copying the other side of the paper together (hereinafter referred to as a stock type) and a method of performing copying on the next sheet after the double-sided copying of one sheet is completed (hereinafter referred to as a non-stock type). .
[0003]
Among them, as one of the above non-stock type copying machines, a paper discharge port that opens a sheet of paper that has been subjected to a copying process on one side by an image forming unit provided inside the copying machine body toward the outside of the copying machine body. The double-sided copying transport unit that is detachably attached to the copying machine main body transports the discharged paper to a refeed port formed in the copying machine main body, and further re-feeds the paper. An apparatus having a configuration in which a sheet is fed again from the paper port to the image forming section through a refeed path is known. By adopting such a configuration, the paper re-feeding mechanism for double-sided copying can be detachably attached to the main body as the above-mentioned double-sided copying transport unit, making the double-sided copying mechanism optional and easy to maintain. There is an advantage such as improvement.
[0004]
By the way, there are many types of recent copiers in which the paper supply tray is housed inside the main body. However, even in this type of copier, a manual feed tray for manually feeding from the outside of the copier main body, that is, paper supplied from the outside. Most of the paper mounting tables for mounting the printer are provided, and the conventional copying machine is no exception.
[0005]
[Problems to be solved by the invention]
In the conventional copying machine having the above-described configuration, the refeeding path for feeding the sheet transported by the duplex copying transport unit as a sheet feeding path from the outside of the copying machine main body to the image forming unit. In general, there are two systems of a manual paper feed path for feeding paper from the manual paper feed tray. However, providing a plurality of paper feed paths of the same system is very wasteful in terms of space efficiency and cost.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a paper circulation device capable of improving space efficiency and reducing costs by sharing a paper feed path from the outside of the device main body to the image forming unit inside the device main body. And an image forming apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to a first aspect includes an apparatus main body, an image forming unit provided in the apparatus main body, a paper feeding unit that feeds paper toward the image forming unit, and the A paper circulation mechanism that circulates the paper on which an image is formed by the image forming unit to the paper feeding unit, a drive unit that drives the paper feeding unit, and detects that the paper has been inserted into the paper feeding unit. A detection unit that outputs the detection signal, a determination unit that determines whether or not the paper circulation mechanism is operating, and the detection signal that is output during the operation of the paper circulation mechanism, In order to start the paper feeding operation by the paper feeding unit,Drive partA sheet feeding control unit that controls the sheet feeding unit, and the sheet feeding unit also serves as a manual sheet feeding unit that can directly feed the sheet, and the sheet feeding control unit is configured to output the detection signal after a predetermined time has elapsed since the detection signal is output. An image forming apparatus is provided that starts a paper feeding operation by a paper feeding unit.
[0008]
According to a second aspect of the present invention, the sheet circulation mechanism is a unit separate from the apparatus main body, and is detachably mounted on a unit mounting portion including a manual paper feed section of the apparatus main body. An image forming apparatus is provided.
[0010]
[Action]
[0011]
According to the first aspect of the present invention, for example, when images are formed on both sides of a sheet, the sheet discharged from the sheet discharge port of the apparatus main body is circulated and supplied to the manual sheet feed port. Is again conveyed to the image forming means. Therefore, it is not necessary to provide a separate sheet feeding path for the paper circulation supply in the apparatus main body, and a single sheet feeding path from the outside of the apparatus main body to the internal image forming means can be unified, and space efficiency Improvement and cost reduction.
Further, during the operation of the paper circulating means, the paper circulated by the paper circulating means is manually fed by starting the paper feeding operation after a predetermined time has elapsed since the detection signal is output from the paper detecting means. After being inserted into the paper feeding unit, the paper feeding for copying can be automatically performed again without operating the copy start button.
[0012]
According to the second aspect of the present invention, since the paper circulation mechanism can be attached to and detached from the main body, it can be attached according to the user's request.
[0014]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention.
[0015]
FIG. 1 is a schematic front view showing an internal configuration of a copying machine according to an embodiment of the present invention.
The copying machine A1 according to the present embodiment, like the copying machine described in the prior art section, performs copying to the next sheet after copying on both sides of one sheet during duplex copying. This is a non-stock type copying machine.
[0016]
As shown in FIG. 1, the copying machine A1 includes an image reading unit 1a that reads a document image and an image forming unit 1b that forms an image on a sheet based on an image read by the image reading unit 1a. A main body 1, an automatic double-sided document feeder (hereinafter referred to as RADF) 2 mounted on a document placing table 3 provided on the upper surface of the image reading unit 1a, and a right side surface of the apparatus body 1 are detachable. And a duplex copying transport unit 4 mounted in a state.
[0017]
The apparatus main body 1 and the RADF 2 constitute an image forming apparatus, and the duplex copying transport unit 4 constitutes a paper circulation device.
[0018]
First, a schematic configuration of the RADF 2 and the image reading unit 1a and an outline of an image reading operation by them will be described. Note that the RADF 2 and the image reading unit 1a are not essential to the present invention, and will be described only briefly.
[0019]
The RADF 2 is configured so that a plurality of documents can be set simultaneously, and the set documents can be automatically conveyed one by one onto a RADF reading area 3a described later. Note that the detailed configuration of the RADF 2 and the description of the document conveying operation are omitted. Further, the image reading unit 1 a includes the document placing table 3, a document placed on the document placing table 3, or a RADF reading area 3 a set at the end of the document placing table 3 by the RADF 2. There is provided a reading optical system 5 for illuminating and scanning a document automatically conveyed on the top and receiving reflected light from the document. Further, the reading optical system 5 receives a fluorescent lamp (not shown), mirrors 6, 7 and 8, a lens 9 for guiding reflected light from the original surface of the light irradiated from the fluorescent lamp, and the reflected light. The line sensor 10 and the like are configured.
[0020]
When the original is transported on the RADF reading area 3a by the RADF 2, the original surface is illuminated and scanned by the reading optical system 5 in a state of being fixed in the positional relationship shown in FIG. Is done. Note that when a copy of a book original is directly placed on the document placing table 3 without using the RADF 2, the document surface is moved by the reading optical system 5 moving from the left to the right in FIG. Illuminated and scanned.
[0021]
Next, a schematic configuration of the image forming unit 1b and the duplex copying transport unit 4 and an outline of an image forming operation by them will be described.
The image forming unit 1b is installed in the apparatus main body 1 so as to be able to be pulled out, and includes paper feed cassettes 11a and 11b on which the paper P is set, and a manual paper feed port for manually setting paper from the outside of the apparatus main body 1. 12, a laser optical system 14 for irradiating the photosensitive member 13 with a laser beam corresponding to an input to the line sensor 10 of the reading optical system 5, an image forming unit 16 for transferring a toner image on the photosensitive member 13, a heat roller A fixing roller 17 configured to fix an image formed on the paper P formed by the image forming unit 16; a paper discharge port 18 through which the paper P that has passed through the fixing roller 17 is discharged; And a paper discharge outlet 19, a paper discharge tray 20 for receiving the paper P discharged from the paper discharge outlet 18, and various transport means (described later) for transporting the paper P between the sections.
[0022]
In the image forming unit 16, a charging charger 25, a developing device 26, a transfer roller 15, and a cleaning roller 27 are arranged around the photoconductor 13 in this order. The image forming unit 16 forms an electrostatic latent image by forming an image of the laser beam from the laser optical system 14 on the outer peripheral surface of the photoconductor 13 uniformly charged by the charging charger 25, and then forms the electrostatic latent image. The electrostatic latent image is developed by the developing device 26.
The toner image is visualized as a toner image, and the toner image is transferred onto the paper P by the transfer roller 15.
After that, the residual toner on the photosensitive member 13 is collected by the cleaning roller 27. Of the image forming section 16, the portions other than the transfer roller 15 are integrally formed as an image forming unit 28 so that the image forming unit 16 can be drawn forward (frontward in the drawing).
[0023]
In the vicinity of the manual feed port 12, a detection switch 35 is provided for detecting the paper P when the paper P is set on the manual feed tray 22 and pressed by the leading end of the paper P to be turned on.
[0024]
A paper feed roller 36 is disposed immediately inside the manual paper feed port 12, and this paper feed roller 36 is a half-moon shaped roller having a flat plate portion 361 with a part of the outer peripheral surface cut out. .
[0025]
Further, similarly, half-moon-shaped sheet feeding rollers 23a and 23b are disposed at the right ends of the sheet feeding cassettes 11a and 11b, respectively. Further, between the paper feed rollers 36, 23a, 23b and the image forming unit 16, the paper fed by the paper feed rollers 36, 23a, 23b is secondarily fed to the image forming unit 16 at a predetermined timing. A registration roller pair 24 is provided.
[0026]
The manual paper feed port 12 constitutes a paper feed port of the main body of the image forming apparatus, the paper discharge port 19 constitutes a paper discharge port of the main body of the image forming apparatus, and the image forming unit 16 and the fixing roller 17 form an image. The detection switch 35 constitutes a paper detection means, the paper feed roller 36 constitutes a manual paper feed means, and the registration roller pair 24 constitutes a secondary paper feed means.
[0027]
The duplex copying transport unit 4 is formed of transport guides 41 and 42 and the like, and is disposed at appropriate positions along the transport path 41 and the transport guides 41 and 42 to guide the transported paper. A pair of transport rollers 38 and a pair of transport rollers 39 are provided to circulate and supply the paper P discharged from one paper discharge port 19 to the manual paper feed port 12 of the apparatus main body 1. The conveyance roller pair 38 and the conveyance roller pair 39 constitute a sheet supply unit.
[0028]
That is, in the copying machine A1, the paper P discharged from the paper discharge port 19 of the apparatus main body 1 is supplied to the manual paper supply port 12, and the paper P is again transferred by the same transport method as in manual paper supply. The image forming unit 16 is configured to convey the image. Thus, the apparatus main body 1 is not provided with a paper feed path from the outside of the apparatus main body 1 to the image forming unit 16 other than the paper feed path at the time of manual paper feeding.
[0029]
As described above, in the copying machine A1, the double-sided copying transport unit 4 is configured as described above, so that the sheet feeding path from the outside of the main body to the image forming unit 16 inside the main body is unified. It is possible to improve the space efficiency and reduce the cost.
[0030]
Further, the double-sided copying transport unit 4 includes a paper discharge port 21 for discharging the paper P discharged from the paper discharge port 19 of the apparatus body 1 without being conveyed to the manual paper feed port 12. In addition, a manual feed tray 22 that is used when the paper P is manually fed to the manual feed port 12 of the apparatus main body 1 is provided. When the manual feed tray 22 is not in use, the manual feed tray 22 can be stored in the side surface of the duplex copying transport unit 4 in the state shown by the broken line in FIG. is there.
[0031]
In addition, the duplex copying transport unit 4 is provided with a detection switch 37 for detecting the storing of the manual feed tray 22 by being turned on when the manual feed tray 22 is stored in the side surface of the duplex copying transport unit 4. Yes. This detection switch 37 constitutes an open / close detection means.
[0032]
Further, a detection switch 71 for detecting the attachment of the duplex copying transport unit 4 is turned on when the duplex copying transport unit 4 is attached to the connecting portion between the apparatus main body 1 and the duplex copying transport unit 4. Is provided.
[0033]
Next, with reference to FIGS. 2 to 4, a mounting configuration of the manual feed tray and the duplex copying transport unit with respect to the apparatus main body will be described. 2 and 3 are perspective views showing the manual feed tray 51 attached to the apparatus main body 1. FIG. 4 is a perspective view showing the duplex copying transport unit 4 attached in place of the manual feed tray 51. FIG.
[0034]
As shown in FIG. 2, the copying machine A1 is provided with a unit mounting portion 50 on the side of the manual paper feed port 12 side. In this unit mounting portion 50, paper supplied from outside is placed. A manual feed tray 51 is attached. The manual feed tray 51 constitutes a paper loading table, and can be stored on the side surface of the apparatus main body 1 in the same manner as the manual feed tray 22, and the manual feed port 12 is closed in the stored state. It is configured.
[0035]
Accordingly, the copying machine A1 is configured such that the double-sided copying transport unit 4 is attached to the apparatus main body 1 after the manual tray 51 attached to the apparatus main body 1 is removed so that the manual paper feed port 12 is not blocked. Has been. That is, as shown in FIG. 3, the manual feed tray 51 is configured to be detachable from the unit mounting portion 50 in a predetermined procedure, and the unit mounting portion 50 from which the manual feed tray 51 is removed is shown in FIG. In addition, the duplex copying transport unit 4 can be mounted.
[0036]
As described above, the unit mounting portion 50 selectively attaches either the manual feed tray 51 or the duplex copying transport unit 4 and constitutes a sheet receiving means.
[0037]
Next, the control system of the copying machine A1 will be described with reference to FIG. FIG. 5 is a block diagram showing a control system of the copying machine A1.
The control unit 60 is composed of a CPU or the like, and controls the operation of each unit of the copying machine A1, and has the following functions.
A function as storage determining means for determining whether or not the manual feed tray 22 is stored in the duplex copying transport unit 4 by turning on and off the detection switch 37.
A function as transport unit discriminating means for discriminating whether or not the duplex copying transport unit 4 is attached by turning on and off the detection switch 71.
Circulation control means for operating each part of the duplex copying transport unit 4 only when the duplex copying transport unit 4 is attached to the apparatus main body 1 and the manual feed tray 22 is housed in the duplex copying transport unit 4 As a function.
As an operation discriminating means for discriminating the operation content of a copy start button 72 for starting a copying operation and a setting button 73 for setting the number of copies, double-sided copying, etc. function.
A function as display control means for controlling the display content of the display unit 74 including, for example, an LCD panel, which is arranged at a suitable position on the surface of the apparatus main body 1 and displays the setting content by the setting button 73 and a warning message.
[0038]
Further, as shown in FIG. 5, the control unit 60 includes a sheet determination unit 61 and a copy control unit 62 as functional blocks.
[0039]
The paper discriminating means 61 discriminates whether or not paper is present in the manual paper feed port 12 by turning on / off the detection switch 35 provided in the manual paper feed port 12 (FIG. 1). When the manual tray 22 is open, the paper discriminating means 61 discriminates whether or not a paper is placed on the manual tray 22, and during double-sided copying, the paper is fed manually from the duplex copying transport unit 4. It is determined whether or not the paper has been circulated and supplied to the paper mouth 12.
[0040]
When the copy start button 72 is pressed, the copy control means 62 starts the operation of each part of the copying machine A1 such as the image forming unit 1b and the RADF 2 according to the operation content on the setting button 73. A determination unit 63 and a paper feed control unit 64 are provided.
[0041]
The mode determination unit 63 performs copying on the sheet placed on the manual feed tray 22 in the duplex copying mode, that is, the duplex copying transport unit 4 is operating, depending on the operation content of the setting button 73. It is determined whether or not the manual paper feed mode is set.
[0042]
The paper feed control means 64 has the following functions.
(1) In the manual paper feed mode, when the copy start button 72 is pressed after it is determined that there is paper in the manual paper feed slot 12, a drive motor or the like connected to the roller shaft of the paper feed roller 36 is formed. A function of starting driving of the driving means 75 and starting a paper feeding operation by the paper feeding roller 36, that is, positive feeding.
(2) In the double-sided copying mode, after it is determined that there is paper in the manual paper feed port 12, the drive of the driving means 75 is started after a predetermined time has elapsed from the time of determination, and the paper is fed by the paper feed roller 36. Function to start operation, ie positive feed.
(3) A function of stopping the flat plate portion 361 of the paper feed roller 36 toward the paper and switching from positive feed to negative feed after the registration roller pair 24 starts to be driven.
[0043]
Here, with reference to FIG. 1, the positive feed and the negative feed by the paper feed roller 36 will be described.
[0044]
The paper placed in the manual paper feed port 12 is first fed primarily by the roller surface of the paper feed roller 36 and sent to the registration roller pair 24, and the leading edge of the paper is nipped between the rollers of the registration roller pair 24. Stop in a slightly bent state. In this way, the conveyance of the paper by applying the conveyance force by the roller surface of the paper feed roller 36 is referred to as positive feeding.
[0045]
Then, the registration roller pair 24 starts rotating in synchronization with the operation timing of the image forming unit 16, and feeds the sheet to the image forming unit 16 in a secondary feed. At this time, the paper feed roller 36 is controlled so that the paper conveyance speed by the registration roller pair 24 becomes unstable due to the friction between the roller surface of the paper feed roller 36 and the paper, and the transfer timing and the image are not shifted. Stops the flat plate portion 361 toward the sheet. As a result, the paper passes through the gap generated by the flat plate portion 361 of the paper feed roller 36, so that an image without deviation is transferred. In this way, allowing the sheet conveyance without applying a conveyance force to the sheet that is secondarily fed by the registration roller pair 24 by directing the flat plate portion 361 of the sheet supply roller 36 to the sheet is referred to as a negative feed. .
[0046]
Next, the outline of the image forming operation by the image forming unit 1b and the duplex copying transport unit 4 and the transport operation of the paper P at that time will be described with reference to FIGS. FIG. 6 is a partially enlarged view of FIG. 1 showing a configuration in the vicinity of the branch guides 29 and 30. Here, the image reading operation by the image reading unit 1a described above is also performed in parallel, and the description thereof is omitted.
[0047]
(Single-sided copy operation)
First, an operation for transferring an image to only one side of the paper P will be described.
[0048]
When the copy start button 72 (FIG. 5) is pressed, the uppermost one of the sheets P in the sheet feeding cassette 11a (or 11b) has a sheet feeding roller 23a (or 23b) having a notch on the outer surface. , And the leading end is abutted between the pair of registration rollers 24. The registration roller pair 24 temporarily waits the paper P at that position, and then conveys the paper P to the image forming unit 16 at a predetermined timing.
[0049]
In the image forming unit 16, a toner image is transferred to one side (photoreceptor side) of the paper P by the above-described method while the paper P passes between the photoconductor 13 and the transfer roller 15. . The sheet P that has passed through the image forming unit 16 is sent to the fixing roller 17, where the toner image is fixed by passing between the heat roller 17a and the pressure roller 17b. When the sheet P that has passed through the fixing roller 17 is discharged face-down (image transfer surface is down), it is discharged face-up (image transfer surface is up) toward the sheet discharge port 18. In this case, the paper is conveyed toward the paper discharge port 19.
[0050]
In this case, the conveyance direction is switched by the operation of the branch claws 29 and 30. That is, if the branch claws 29 and 30 are in the state indicated by the solid lines in FIG. 6, the paper P is guided toward the paper discharge port 18, and the branch claws 29 and 30 are in the state indicated by the broken lines in FIG. The paper P is guided toward the paper discharge port 19.
[0051]
The paper P guided in the direction of the paper discharge port 18 is discharged from the paper discharge port 18 by a pair of discharge rollers 31 and 31 and is accumulated on the paper discharge table 20 in a face-down state. On the other hand, the paper P guided in the direction of the paper discharge port 19 is discharged from the paper discharge port 19 by a pair of discharge rollers 32 and 32 and is transported into the duplex copying transport unit 4.
[0052]
The sheet P transported into the duplex copying transport unit 4 is guided by a branching claw 33 set in a state indicated by a broken line in FIG. 6, and is further discharged from the sheet discharge outlet 21 by a pair of discharge rollers 34 and 34. The The paper P discharged from the paper discharge port 21 is accumulated face-up on, for example, a separate finisher (not shown). When the duplex copying transport unit 4 is not attached to the apparatus main body 1, the sheet P discharged face-up from the discharge port 19 is, for example, a separate finisher (not shown). Accumulated on top.
[0053]
Further, when the paper P is fed manually instead of from the paper feed cassettes 11a and 11b, the leading end of the paper P is placed on the manual feed tray 22 attached to the duplex copying transport unit 4. The main body 1 is placed in the state of being inserted into the manual paper feed port 12. The state in which the paper P is set on the manual feed tray 22 is detected by pressing the detection switch 35 at the front end of the paper P. Thereafter, when the copy start button 72 (FIG. 5) is pressed, the control unit 60 (FIG. 5) installed in the apparatus main body 1 detects the detection signal from the detection switch 35 and the copy start button 72 (FIG. 5). The rotation of the paper feed roller 36 is started by the copy start signal from. As a result, the uppermost one of the sheets P on the manual feed tray 22 is pulled out and conveyed in the direction of the pair of registration rollers 24.
[0054]
The operation after the start of rotation of the paper feed roller 36 is the same as that in the case of paper feed from the paper feed cassettes 11a and 11b described above. The operation procedure from the detection of the paper by the detection switch 35 to the start of rotation of the paper feed roller 36 will be described later with reference to FIG.
[0055]
When manual feeding is performed in a state where the duplex copying transport unit 4 is not attached to the apparatus main body 1, a manual tray 51 attached to the apparatus main body 1 may be used as shown in FIG.
[0056]
(Double-sided copy operation)
Next, an operation when images are transferred onto both sides of the paper P will be described.
[0057]
First, as a first precondition for performing duplex copying, the duplex copying transport unit 4 needs to be attached to the apparatus main body 1. This is detected by a detection switch 71 provided at a connection portion between the duplex copying transport unit 4 and the apparatus main body 1.
[0058]
Further, in this copying machine A1, paper feeding can be performed manually even when the duplex copying transport unit 4 is attached to the apparatus main body 1, but it is basically possible to perform duplex copying in the state of manual feeding. It may not be desirable. This is because during double-sided copying, the double-sided copying transport unit 4 supplies the single-side copied paper P discharged from the paper discharge port 19 of the apparatus main body 1 to the manual paper supply port 12 of the apparatus main body 1. In the state where the paper P is set in the manual paper feed port 12, the single-sided copied paper P passes through the set paper P, so that the frictional force when passing through the single-sided copied paper P is passed. As a result, the paper P set in the manual paper feed port 12 also moves somewhat in the paper feeding direction, and the paper feed position is shifted. Further, when the set paper P is smaller than the size of the single-sided copied paper P, there is a difference in level when the single-sided copied paper P is fed between where the set paper P is present and where it is not. This is because the conveyance becomes unstable. However, there is no problem if all the sheets P set in the manual sheet feeding port 12 have been fed before the one-sided copied sheet P reaches the manual sheet feeding port 12.
[0059]
As a second precondition for performing double-sided copying, when it is necessary that the paper P is not set in the manual paper feed port 12, the copying machine A1 satisfies this second precondition. It is determined by detecting whether or not the paper P is in a state where it can be manually set. Specifically, the detection signal of a detection switch 37 provided to detect the state where the manual feed tray 22 is stored on the side surface of the duplex copying transport unit 4 is turned ON by the control unit 60 (the manual feed tray 22 is stored). State), it is determined that the paper P cannot be manually set, that is, the second precondition is satisfied. As a result, it is possible to prevent an accident due to double-sided copying with the paper P set in the manual paper feed port 12.
[0060]
Next, the operation when transferring an image to both sides of the paper P will be specifically described.
When starting double-sided copying, the user sets double-sided copying using the setting button 73, but the control unit 60 detects from the detection switch 71 that detects the connection between the duplex copying transport unit 4 and the apparatus main body 1. Until the signal and the detection signal from the detection switch 37 are received, control is performed so that the duplex copy setting cannot be selected. In this case, duplex copying can be set only when the first and second preconditions are satisfied.
[0061]
FIG. 7 is a flowchart showing an operation procedure up to the start of double-sided copying.
As shown in the figure, first, when the duplex button is set by the setting button 73 with the duplex copying transport unit 4 attached, the copy start button 72 is pressed (YES in step S11). Whether or not the manual feed tray 22 is in the closed state is determined based on the presence or absence of a detection signal from the detection switch 37 (step S12). If the manual feed tray 22 is in the closed state (YES in step S12), double-sided copy processing described later is started (step S15), and if it is in the open state (NO in step S12), the copy start button 72 is disabled (step S12). S13) For example, a warning message such as “Please close the manual feed tray” is output to the display unit 74 (step S14), and the process returns to step S11 again.
[0062]
When the double-sided copying process in step S15 is started, the paper P in the paper feed cassette 11a (or 11b) is conveyed through the image forming unit 16 and the fixing roller 17 in the same manner as in the case of single-sided copying. In the process, an image is formed on one side. The sheet P that has passed through the fixing roller 17 is guided by the branching claws 29 and 30 set in the state indicated by the solid line in FIG. 6 and conveyed toward the sheet discharge port 18, and is discharged from the leading end by the discharge rollers 31 and 31. The paper is sequentially discharged out of the paper discharge port 18. Then, the rotation of the discharge rollers 31, 31 is stopped in a state where the rear end portion of the paper P is sandwiched. That is, the paper P is discharged onto the paper discharge tray 20 with only the rear end portion remaining in a face-down state.
[0063]
Subsequently, after the branch claws 29 and 30 are set in the state shown by the broken line in FIG. 6, the discharge rollers 31 and 31 start to rotate in the reverse direction. As a result, the sheet P is again drawn into the discharge port 18, guided toward the discharge port 19 by the branch claws 29, 30, and discharged by the discharge rollers 32, 32. With the above switchback operation, the front and back of the paper P are reversed with respect to the transport direction.
[0064]
The paper P discharged from the paper discharge port 19 is transported as it is into the duplex copying transport unit 4. The sheet P transported into the duplex copying transport unit 4 is guided by the branching claw 33 set in the state shown by the solid line in FIG. 1 and further transported by the transport rollers 38, 38, the paper circulation path 43, the transport rollers 39, 39, and the leading end is inserted into the manual sheet feeding port 12. When the leading edge of the paper P is inserted into the manual paper feed port 12, the state is detected by the detection switch 35. After receiving the detection signal from the detection switch 35, the control unit 60 starts the rotation of the paper feed roller 36 at a predetermined timing. The operation procedure from the detection of the paper by the detection switch 35 to the start of rotation of the paper feed roller 36 will be described later with reference to FIG.
[0065]
When the paper feed roller 36 rotates, the paper P is thereby transported in the direction of the registration roller pair 24, and is then transported again through the image forming unit 16 and the fixing roller 17 in order. An image is formed on one side. The paper P that has passed through the fixing roller 17 is guided by the branching claws 29 and 30, conveyed toward the paper discharge port 18 or the paper discharge port 19, and discharged.
[0066]
The double-sided copying operation has been described above. In this double-sided copying operation, the paper is circulated and supplied without performing the front / back reversing operation of the paper by the switchback operation, that is, after the paper P passes through the fixing roller 17. If the branching claws 29 and 30 are in the state shown by the broken lines in FIG. 6 and the paper P is guided toward the paper discharge port 19, the composite copying is performed in which the copying is performed only on one side of the paper, not the double-sided copying. be able to.
[0067]
FIG. 8 is a flowchart showing an operation procedure from detection of a sheet by the detection switch 35 to start of rotation of the sheet feed roller 36.
In the figure, first, when the detection switch 35 detects a sheet in the manual sheet feeding port 12 (YES in step S21), it is then determined whether double-sided copying or manual sheet feeding is performed (step S22). When (NO in step S22), when the copy start button 72 is turned on (YES in step S23), rotation of the paper feed roller 36 is started (step S25).
[0068]
On the other hand, in the double-sided copying mode (YES in step S22), the process waits until a predetermined time elapses from the time point when the detection switch 35 detects the paper (NO in step S24), and when the predetermined time elapses (YES in step S24), The rotation of the paper feed roller 36 is started (step S25).
[0069]
Such a control is necessary because the copying machine A1 uses the paper feed path for manual feeding as part of the paper circulation path for duplex copying. That is, the paper feed roller 36 is not always driven to rotate, and rotates only when necessary to convey the paper P by a predetermined amount. It is necessary to start rotation.
[0070]
As described above, in the copying machine A1 according to the present embodiment, the duplex copying transport unit 4 that is detachably attached to the apparatus main body 1 feeds the paper P discharged from the paper discharge port 19 to the manual paper feed. It is configured to be supplied to the port 12, and at the time of duplex copying, the paper P is conveyed again to the image forming unit 16 through the same paper circulation path as that in the case of manual paper feeding. Accordingly, it is not necessary for the apparatus main body 1 to provide a paper feed path from the outside of the apparatus main body 1 to the image forming unit 16 other than the paper feed path at the time of manual feeding. Therefore, in this copying machine A1, it is possible to unify the sheet feeding path from the outside of the apparatus main body 1 to the internal image forming unit 16, thereby improving the space efficiency and reducing the cost.
[0071]
Further, in the copying machine A1 according to the present embodiment, in the double-sided copying mode, the paper feeding operation by the paper feeding roller 36 is performed after a predetermined time has elapsed since the paper was detected at the manual paper feeding port 12 by the detection switch 35. By starting the operation, the sheet feeding operation of the sheet feeding roller 36 as the manual sheet feeding unit can be suitably performed even in the duplex copying mode.
[0072]
In addition, this invention is not restricted to the said embodiment, The following modifications can be employ | adopted.
(1) In the copying machine A1 according to the above-described embodiment, the paper feed roller 36 is a roller having a flat plate portion 361, and is rotated and positively fed by the roller surface to stop the flat plate portion 361 toward the paper. However, the present invention is not limited to this.
[0073]
FIG. 9 is a partial front view of the copying machine A1 provided with different manual sheet feeding means.
The paper feed roller 362 is formed of a cylindrical roller, and the roller shaft 363 and the drive shaft 751 of the motor (drive means) 75 are connected via a one-way clutch 364. The one-way clutch 364 includes a stopper that restricts rotation in one direction. When the paper feed roller 362 rotates clockwise with respect to the roller shaft 363, that is, in the direction of feeding paper, the paper feed roller 362 is moved to the roller shaft. It is rotated independently with respect to 363.
[0074]
In this configuration, when a driving force is transmitted from the motor 75 and a force is applied to the roller in a counterclockwise direction due to friction between the peripheral surface of the paper feed roller 362 and the paper, the one-way clutch 364 causes the paper feed roller 362 to move to the roller shaft. Since it is fixed with respect to 363, it follows the movement of the roller shaft 363. As a result, positive feeding is performed, and the leading edge of the paper comes into contact with the registration roller pair 24 and stops in a slightly bent state.
[0075]
When the registration roller pair 24 starts rotating, the sheet is conveyed toward the image forming unit 16. At this time, the rear end side of the paper is still pressed by the paper feed roller 362, but when the paper is pulled by the registration roller pair 24, the paper feed roller 362 is free from the roller shaft 363 by the one-way clutch 364. Therefore, the rear end side of the sheet is sent out, and thereby depolarization feeding is performed.
[0076]
In this case, the paper feed control means 64 in FIG. 5 has the following functions.
(A) In the manual paper feed mode, when the copy start button 72 is pressed after it is determined that there is paper in the manual paper feed slot 12, the drive unit 75 starts to be driven and is fed by the paper feed roller 362. Function to start paper movement, that is, positive feed.
(B) In the double-sided copying mode, after it is determined that there is a sheet in the manual sheet feeding port 12, the drive of the driving unit 75 is started after a predetermined time has elapsed from the determination point, and the sheet is fed by the sheet feeding roller 362. Function to start operation, that is, positive feed.
(C) A function of stopping the rotation of the paper feed roller 362 and switching from positive feed to negative feed after the registration roller pair 24 starts to be driven.
[0077]
As described above, even when the cylindrical paper feed roller 362 provided with the one-way clutch 364 is used, the positive feeding and depolarization feeding of the paper can be suitably performed as in the above embodiment.
(2) The copying machine A1 according to the embodiment is configured such that the double-sided copying transport unit 4 is attached to the apparatus main body 1 after the manual feed tray 51 attached to the apparatus main body 1 shown in FIG. Has been. This is because when the manual copying tray 51 of the apparatus main body 1 is accommodated in the apparatus main body 1 in the same manner as the manual tray 22 and the duplex copying transport unit 4 is attached, the manual feeding tray 51 accommodates the manual feeding tray 51. This is because the sheet feeding port 12 is blocked.
[0078]
Therefore, as the manual feed tray to be attached to the apparatus main body 1, the one having an opening at a position corresponding to the manual paper feed port 12 when stored in the apparatus main body 1 is used to store the manual tray in the apparatus main body 1. In addition, the manual sheet feeding port 12 is not blocked. This eliminates the need to remove the manual feed tray attached to the apparatus main body 1 when the duplex copying transport unit 4 is attached to the apparatus main body 1.
[0079]
10 is a perspective view showing a state in which a manual feed tray 52 having an opening is housed in the apparatus main body 1. FIG. 11 is a partial front view showing a state in which the duplex copying transport unit 4 is attached to the apparatus main body 1 in FIG. It is.
[0080]
As shown in FIG. 11, the apparatus main body 1 includes a manual feed tray 52 and a detection switch 56. As shown in FIG. 10, the manual feed tray 52 includes a rotating portion 54 that can be rotated outwardly around the support shaft 53 in a state of being accommodated in the apparatus main body 1, and the rotating portion 54 faces outward. It has the opening part 55 formed by rotating. As shown in FIG. 11, the opening 55 is formed at a position corresponding to the manual paper feed port 12 of the apparatus main body 1, so that even if the manual tray 52 is stored in the apparatus main body 1, the manual paper feed port 12 is formed. Will not be blocked.
[0081]
The detection switch 56 is disposed at the storage position of the manual feed tray 52, and is turned on when the manual feed tray 52 is stored to detect the storage of the manual feed tray 52, and constitutes an open / close detection means.
[0082]
In this embodiment, the control unit 60 has a function as storage determination means for determining whether or not the manual feed tray 52 is stored in the apparatus main body 1 by turning on and off the detection switch 56 as indicated by a broken line in FIG. Each part of the duplex copying transport unit 4 is stored only when the manual feed tray 52 is stored, the duplex copying transport unit 4 is attached to the apparatus main body 1, and the manual tray 22 is stored in the duplex copying transport unit 4. It has a function as a circulation control means for performing the operation.
[0083]
(3) The copying machine A1 according to the above embodiment is provided with the detection switch 37 for detecting the state that the manual feed tray 22 is housed on the side surface of the duplex copying transport unit 4 in the duplex copying transport unit 4. If the detection signal of the detection switch 37 is on (the manual feed tray 22 is in the stored state), it is determined that the paper P cannot be manually set, that is, the second precondition is satisfied. However, the method for determining whether or not the second precondition is satisfied is not limited to this. For example, it is determined whether or not the second precondition is satisfied by detecting the presence or absence of the paper P set on the manual feed tray 22 based on the paper detection signal from the detection switch 35. May be.
[0084]
(4) In the copying machine A1 according to the above embodiment, in the double-sided copying mode, after it is determined that there is a sheet in the manual sheet feeding port 12, a sheet is fed by the sheet feeding roller 36 after a predetermined time has elapsed from the determination point. Although the operation is automatically started, this is applied when the document is automatically conveyed. When the original is not automatically conveyed, after copying on one side is finished and it is determined that there is paper in the manual paper feed slot 12, after the original is set on the other side, for example, the copy start button 72 is operated. Accordingly, the sheet feeding operation by the sheet feeding roller 36 may be started.
[0085]
(5) In the copying machine A1 according to the above embodiment, the double-sided copying transport unit 4 is detachable from the apparatus main body 1. However, it is not always necessary to be detachable. It may be attached.
[0086]
【The invention's effect】
The present invention includes a paper feed unit that feeds paper toward the image forming unit, and a paper circulation mechanism that circulates the paper on which an image is formed by the image forming unit to the paper feed unit.A drive unit that drives the paper feed unit, a paper detection unit that detects that a paper has been inserted into the paper feed unit, and outputs a detection signal thereof, and determines whether or not the paper circulation mechanism is operating And a paper feed control unit that controls the drive unit to start a paper feed operation by the paper feed unit when a detection signal is output during the operation of the paper circulation mechanism.The paper feed unit also has a manual paper feed function capable of directly feeding paper, so that, for example, when an image is formed on both sides of the paper, the paper ejected from the paper ejection port Since the paper is circulated and supplied to the manual paper feed unit and the paper is conveyed again from the manual paper feed unit to the image forming unit, it is not necessary to provide a dedicated paper feed path for the paper circulation supply in the apparatus main body. .Further, the paper feed control unit starts the paper feed operation by the paper feed unit after a predetermined time has elapsed from the time when the detection signal is output, thereby detecting from the paper detection unit during the operation of the paper circulation unit. By starting the paper feeding operation after a predetermined time has elapsed from the time when the signal is output, after the paper circulated by the paper circulating means is inserted into the paper feeding section of the manual paper feeding means, the copy start button It becomes possible to automatically feed paper for copying again without any operation.
[0087]
Further, the sheet circulation mechanism can be detached from the apparatus main body by the unit mounting portion, and can be attached according to the user's request.
[0089]
[Brief description of the drawings]
FIG. 1 is a schematic front view showing an internal configuration of a copying machine according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a manual feed tray attached to the apparatus main body.
FIG. 3 is a perspective view showing a manual feed tray attached to the apparatus main body.
FIG. 4 is a perspective view showing a duplex copying transport unit attached instead of a manual feed tray.
FIG. 5 is a block diagram showing a control system of the copying machine.
FIG. 6 is a diagram showing a configuration in the vicinity of a branch guide. FIG.
FIG. 7 is a flowchart showing an operation procedure up to the start of double-sided copy processing.
FIG. 8 is a flowchart illustrating an operation procedure from detection of a sheet by a detection switch to start of rotation of a sheet feeding roller.
FIG. 9 is a partial front view of a copying machine provided with different manual sheet feeding means.
FIG. 10 is a perspective view illustrating a state in which a manual feed tray having an opening is stored in the apparatus main body.
11 is a partial front view showing a state in which a duplex copying transport unit is mounted on the apparatus main body of FIG.
[Explanation of symbols]
A1 Copier body
1a Image reading unit
1b Image forming unit
1 Main unit
3 Document placement table
2 Automatic duplex document feeder (RADF)
4 Double-sided copy transport unit
3a Reading area for RADF
5 Reading optical system
6, 7, 8 Mirror
9 Lens
10 Line sensor
11a, 11b Paper feed cassette
12 Manual feed slot
13 Photoconductor
15 Transfer roller
14 Laser optics
16 Imaging Department
17a Heat roller
17b Pressure roller
17 Fixing roller
18, 19 Paper exit
20 Output tray
21 Paper exit
22 Bypass tray
22a fulcrum
23a, 23b Paper feed roller
24 Registration roller pair
25 Charger charger
26 Developing device
27 Cleaning roller
28 Image creation unit
29, 30 Branch guide (branch claw)
31, 32 Discharge roller
33 Branch claw
34 Discharge roller
35 Detection switch
36 Paper feed roller
37 Detection switch
38, 39 Pair of transport rollers
361 Flat plate
362 paper feed roller
363 Roller shaft
364 one-way clutch
37 Detection switch
41, 42 Transport guide
43 Paper circulation path
50 Unit mounting part
51, 52 Bypass tray
56 detection switch
60 Control unit
61 Paper discrimination means
62 Copy control means
63 Mode determination means
64 Paper feed control means
71 Detection switch
72 Copy start button
73 Setting button
74 Display
75 Drive means (motor)

Claims (5)

An apparatus main body, an image forming unit provided in the apparatus main body, a paper feeding unit that feeds paper toward the image forming unit, and a paper on which an image is formed by the image forming unit. A paper circulation mechanism that circulates and supplies the paper, a drive unit that drives the paper feed unit, a paper detection unit that detects that a paper has been inserted into the paper feed unit, and outputs a detection signal thereof, and the paper circulation A determination unit that determines whether or not the mechanism is operating; and when the detection signal is output during the operation of the paper circulation mechanism, the drive unit is controlled to start a paper feeding operation by the paper feeding unit A paper feed control unit that also serves as a manual paper feed unit that can directly feed paper, and the paper feed control unit is configured to feed the paper feed after a predetermined time has elapsed since the detection signal is output. Image formation characterized by starting paper feeding operation Location. The image forming apparatus according to claim 1, wherein the paper circulation mechanism is a unit separate from the apparatus main body, and is detachably mounted on a unit mounting portion including a manual paper feed unit of the apparatus main body. . A secondary paper feed unit interposed between the paper feed unit and the image forming unit and configured to secondary feed the paper fed by the paper feed unit toward the image forming unit; The paper section is configured to positively feed a sheet inserted into a sheet feeding port provided in the sheet feeding section to feed the sheet to the secondary sheet feeding section and to perform secondary feeding by the secondary sheet feeding section. 3. The image according to claim 1, wherein the paper feeding operation is started by selectively performing a negative feed that allows paper conveyance without applying a conveyance force to the paper to be printed. 4. Forming equipment. The paper feeding unit is a half-moon shaped roller having a flat plate part with a part of the outer peripheral surface cut out, and the positive feeding unit is configured to make the positive feeding by bringing the outer peripheral surface excluding the flat plate part into contact with the paper. When the secondary paper feeding is performed by the secondary paper feeding unit, the negative feed is performed by stopping the driving unit with the flat plate portion facing the paper. The image forming apparatus according to claim 3. A one-way clutch that is interposed between the drive unit and the paper feed unit and disconnects the drive unit and the manual paper feed unit when the paper is pulled by the secondary paper feed; The drive unit performs the positive feed by driving the drive unit, and performs the negative feed by stopping the drive unit when the secondary paper feed is performed by the secondary paper feed unit. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus.

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