JPH0428677A - Image forming device - Google Patents

Abstract

PURPOSE:To make a device main body compact and facilitate elimination of a jammed sheet by providing a double surface unit to be detachably installed at the device main body, a resupply unit to be freely drawn from the double surface unit, and an inversion unit to be freely opened and closed in the device main body. CONSTITUTION:When a paper jam occurs on both sides, an inversion unit 70 is opened as illustrated, and a resupply unit 77 is drawn from a double surface frame 69, so a jammed sheet can be taken out easily. Because the inversion unit 70, resupply unit 77, and both sides, etc., of the double surface frame 69 are composed to be detachably installed to a device main body 2, an image forming device can be composed easily by manufacturing the device main body 2 side and the double surface frame 69 side by different makers, and connecting them with each other, and the maintenance property such as parts replacement and reparing can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an image forming apparatus with a double-sided printing function that can form images on both sides of a sheet of paper as needed.

(B) Prior art An example of a conventional image forming apparatus with a double-sided printing function is shown in FIG. A paper storage cassette 3 is detachably mounted, and a paper feed roller 5 and a separation pad 6 that presses against the roller 5 to separate the paper S are provided on the downstream side thereof. On the downstream side of the paper feed roller 5, a pair of upper and lower registration rollers 7 and an image carrier 9 are sequentially arranged. The scanner unit 10 irradiates the image carrier 9 with laser light according to external information to form a latent image.

The process cartridge 11 containing the image bearing member 9 includes various functional units that form a toner image on the image bearing member 9 using a well-known electrophotographic method. An image transfer device 12 for transferring the toner image onto the paper S is arranged below the image carrier 9, and a guide plate 13 for transporting the paper, a fixing device 15, etc. are sequentially arranged downstream of the image transfer device 12. .

On the downstream side of the fixing device 15, a support shaft 16a connects the main body 2 of the apparatus.
A paper reversing unit 16 is provided which is rotatably connected to the paper reversing unit 16 . The paper reversing unit 16 includes a face-up paper discharge tray 17, a face-down/duplex switching flapper 19, and a duplex/face-up switching flapper 2o.
, a discharge path 21, a pair of reversing rollers 22, a reversing conveyance path 25, and the like. Further, a refeeding route 27 is provided at the bottom of the main body frame 26, and this refeeding route 27
It is composed of an entrance guide 29 connected to the downstream side of the reversing conveyance path 25, an entrance conveyance roller 30, a lateral registration guide member 31, a refeed roller 32, a refeed path 33, and the like.

The paper S fed from the paper storage cassette 3 by the paper feed roller 5 has a toner image transferred thereto from the image carrier 9 , and then the toner image is further fixed by the fixing device 15 .

When performing double-sided recording on the paper S, the paper S is guided to the paper reversing unit 16 by two flappers 19 and 20. Of the two flappers 19 and 20, after the double-sided/face-up switching flapper 20 is switched to the double-sided side, the face-down/both-sided switching flapper 19 can be switched.

The paper S discharged by the reversing roller 22 that rotates in the direction of the arrow is conveyed through the reversing conveyance path 25 by the reversing roller 22 that rotates in the direction opposite to the arrow when the trailing edge is detected by the reversing sensor 35, and is then conveyed through the reversing conveyance path 25 by the reversing roller 22 that rotates in the direction opposite to the arrow. is conveyed to the lateral registration guide member 31 by. The paper S, which is re-fed from the lateral registration guide member 31 by the re-feed roller 32, is subjected to double-sided recording by transferring a toner image to the back side by the image carrier 9.

FIG. 14 shows another conventional image forming apparatus B with a double-sided printing function. In the figure, the image forming process from the paper storage cassette 3 to the fixing device 15 has the same configuration as in the 13th section. A discharge/duplex switching flapper 37 is provided on the downstream side of the fixing device 15, and an intermediate roller 39 and a ball discharge roller 40 are provided on the downstream side above the flapper 37.
, a paper discharge tray 41, and the like are sequentially arranged.

Further, on the lower double-sided paper refeeding side, there is an introduction guide plate 42, an entrance conveyance roller 43, a conveyance guide plate 45, and a reversal sensor 4.
6 and an exit conveyance roller 47 are provided.

Further, a reversing guide 50 is provided to protrude from the device main body 2. A refeeding path 56 is constituted by this reversing guide 50, a lateral registration guide plate 51, a pair of refeeding rollers 52, a refeeding flapper 53, a refeeding guide 55, and the like.

When performing double-sided recording on the sheet S, the sheet S recorded on one side by the fixing device 15 is conveyed onto the reversing kite 50 via the introduction guide plate 42 and the conveyance guide plate 45. The paper S re-fed by the re-feed roller pair 52 is conveyed to the image carrier 9 via the re-feed guide 55, where the toner image is transferred to the back side and fixed by the fixing device 15 for double-sided recording. will be carried out.

(C) Problems to be Solved by the Invention However, in the image forming apparatus A shown in FIG. Since there is a limit to the ejection angle of the paper S after fixing the image, for this reason, the paper reversing unit 16
It has a structure that greatly protrudes rearward from the device main body 2.

Therefore, when double-sided printing is specified, the single-sided recording paper S is conveyed until the trailing edge of the paper is detected by the reversing sensor 35, so the leading edge of the paper protrudes further rearward than the end of the paper reversing unit 16tlt. This poses a problem in that the image forming apparatus A requires a large installation space.

Furthermore, if a paper jam occurs in the reversing conveyance path 25 or the refeeding path 27, the paper reversing unit 16 itself has a structure that protrudes rearward, so the sheet reversing unit 16 can be rotated around the spindle 16a. It is extremely difficult to remove jammed paper. Therefore, it is necessary to provide a maintenance space 56 for removing jammed paper from the side of the apparatus, making it impossible to downsize the apparatus.

Next, in the image forming apparatus B shown in FIG. 14, the paper S that has passed through the fixing device 15 curls, especially when the fixing device 15 is a heat fixing type.
It is necessary to make the conveyance path as straight as possible until it cools down, or in the case of a curved conveyance path, it is necessary to use a conveyance path with a large curvature. Therefore, jam removal in the double-sided paper refeeding section of image forming apparatus B has been ensured, and the reversing guide 50 has a structure that protrudes from the apparatus main body 2. However, it was difficult to miniaturize the device.

Furthermore, the double-sided conveyance mechanism of both image forming apparatuses A and B mentioned above is not only reliable in terms of mechanical precision and electrical connection to the apparatus main body 2, but also complicated and safe when installing the double-sided conveyance mechanism. Furthermore, there were many restrictions on the exterior processing, and it was common for manufacturers of image forming apparatuses to create them. Therefore, maintenance such as maintenance inspection, parts replacement, and repair of the reversing section and duplex section of the paper S is extremely poor, and in addition to the above-mentioned jam handling performance, the contradictory conditions of miniaturizing the device and securing space for jam handling are required. There was a problem that had to be satisfied.

Therefore, the present invention has a structure in which a duplex unit housing a refeeding unit is configured to be detachable from the main body of the apparatus, the refeeding unit can be freely pulled out from the duplexing unit, and the paper that has been recorded on one side is refeeded. An image forming apparatus that has a reversing unit that is attached to the unit so that it can be opened and closed with respect to the main body of the apparatus, thereby reducing the size of the main body of the apparatus and facilitating the removal of jammed paper in the reversing unit and refeeding unit. The purpose is to provide the following.

(Means for solving the gradient problem) The present invention has been made in view of the above-mentioned circumstances, and for example, when shown with reference to FIGS.
2) Transfer the image formed on the image carrier (9) to the paper (S).
The image is transferred to the front bent paper (S) by the fixing device (15), and the transport direction of the paper (S) is selectively switched by the switching means (62) to perform single-sided recording or double-sided recording. In the forming device, the forward bending device main body (2) includes a detachable double-sided frame (69) and the switching means (62).
It has a reversing rotation means (72) and a reversing conveyance path (76) for guiding the paper (S) branched and conveyed by the double-sided frame (69), and can be opened and closed with respect to the apparatus main body (2). A reversing unit (70) is attached to the double-sided frame (69) so that the paper conveyed from the reversing unit can be re-fed to the image carrier and can be freely pulled out from the double-sided frame (69). The refeeding unit (7) disposed within the double-sided frame (69)
7).

(e) Function When double-sided recording is performed on paper based on the above configuration, the paper (S) after the image is fixed on one side is re-fed into the double-sided frame (69) via the reversing unit by the switching means (62). It is transported to the feeding unit (77), and further transported to the main body (2).
) is re-fed to the image carrier (9) and images are formed on both sides.

The reversing unit (70) and the refeeding unit (77)
If a paper (S) jam occurs in the machine, the jam can be removed by opening the reversing unit (70) from the main body (2) or pulling out the refeeding unit (77) from the double-sided frame (69). The printed paper (S) can be easily removed without providing a maintenance space, and the image forming apparatus can be downsized.

In addition, since the single-sided frame (69) is removable from the apparatus main body (2), the double-sided frame (69) equipped with the refeeding uni-soto (77) and the reversing unit (70) can be attached to the apparatus main body (2). can be manufactured separately, which facilitates the manufacturing of the image forming apparatus.

Note that the above-mentioned symbols in parentheses are shown for reference to the drawings, and are not intended to limit the structure of the present invention in the same manner.

(F) Example Hereinafter, a first example of the present invention will be described based on FIGS. 1 to 8. Note that the same parts as shown in FIG. 13 are denoted by the same reference numerals.

In FIG. 1, a pre-registration sensor 60 is disposed on the upstream side of the registration roller rough, and the sensor 57 separates and feeds the paper S one by one by the paper feed roller 5 and separation pad 6. , the conveyance is started in time with the image writing on the image carrier 9. A fixing sheet discharge sensor 61 is provided downstream of the fixing device 15 to detect the sheet S after being fixed.

A paper discharge/duplex switching flapper (switching means) 62 is disposed downstream of the fixing paper discharge sensor 61.
On the downstream side, there is an intermediate roller 63 and a curved paper ejection guide 6.
5 and a paper ejection roller 66, etc., and sheets S designated for single-sided printing are ejected and stacked onto a paper ejection tray 67 at the top of the main body 2 of the apparatus.

At the bottom of the device main body 2, there is a double-sided frame 6 for storing both sides.
9 is attached as described later, and the base of the reversing unit 70 is attached to the support shaft 7 at the rear (left side in the figure).
It is attached so that it can be opened and closed by 0a. When the reversing unit 70 is in the closed position as shown in FIG.
2 are arranged in sequence, and a reversal sensor 73 is provided in the middle of the reversal introduction guide 71.
A reversing guide 75 is provided downstream of the upper side of the reversing roller pair 72.
It is provided integrally or separably with the reversing unit 70.

Further, on the downstream side of the reversing guide 75 and below the pair of reversing rollers 72, a reversing conveyance path 76 is formed to guide the paper S from the reversing guide 75 to the double-sided frame 69. A refeeding unit 77 is provided inside the double-sided frame 69, and by pulling out or pushing in a handle 77a formed on the front part of the refeeding unit 77, the rail 69a ( (see FIG. 3) and can be inserted into and removed from the double-sided frame 69.

Inside the refeeding unit 77, a double-sided log guide member 78 for guiding the paper S from the reversing conveyance path 76 is provided.On the downstream side thereof, a conveyance roller 79a and a pressure roller that can come into contact with and separate from the conveyance roller 79a are provided. The first conveying roller pair 7 consisting of 79b
9. A pair of left and right lateral registration regulation guides 80, 81, a second transport roller pair 82 consisting of a transport roller 82a and a pressure roller 82b that can come into contact with and separate from this, and the paper S in the refeed unit 77 are moved to the upper device. Paper refeed guide members 84 and the like that guide the paper S into the main body 2 are sequentially arranged in accordance with the transport direction of the paper S. Furthermore, a paper detection sensor 85 for detecting the leading edge of the paper S is disposed downstream of the lateral registration regulation guides 80.81.

Further, the refeeding unit 77 includes a drive system 86 that drives the first conveyance roller pair 79 and the refeeding guide member 84.
A drive system 87 and a drive control system 89 for driving the lateral registration regulation guides 80 and 81 are provided, respectively.

At the rear part of the refeeding unit 77, a drawer restricting lever 90 having a protrusion 90a on the upper part is pivoted by a support shaft 91, and the lower end of the drawer restricting lever 90 is connected to a compression spring 92 engaged with a fixing member. The stopper 9 provided on the refeeding unit 77 is biased counterclockwise by the
Rotation is restricted by 3. In addition, the main frame 2
A stopper 26a that engages with the protrusion 90a is formed at the front of the lower surface of 6. The slit 26b formed in the main body frame 26 communicates with a pair of paper refeeding guide plates 95 provided in the apparatus main body 2.

6 and 7, a plurality of positioning protrusions 96 are provided on the main body frame 26 of the device main body 2,
By engaging this protrusion 96 with a positioning hole 97 formed in the upper plate 69b of the double-sided frame 69, the double-sided frame 69 can be positioned in the apparatus main body 2 at an appropriate position. Reference numeral 99 is a connector that electrically connects the double-sided frame 69 and the main body 2 of the apparatus.

Further, as shown in FIG. 6, a pair of latches 100 each having a locking claw 100a at the upper part are pivotally attached to the double-sided frame 69 by a support shaft 101.
Both ends of the link 102 are rotatably connected by a support shaft 103, so that the two latches 100 extending upwardly from the holes 69c bored in the upper plate 69b of the link 102 can be interlocked. The link 102 is biased forward by the elasticity of a tension spring 105 whose one end is locked to the double-sided frame 69, and the side of the latch 100 is connected to the hole 69c.
Rotation is regulated by making it come into contact with the side part of.

Further, the main body frame 26 of the apparatus main body 2 is provided with a plurality of engagement holes 106 into which the latches 100 are engaged.

Based on the above configuration, the operation of this embodiment will be explained.

The paper S fed from the paper storage cassette 3 and having the toner image transferred on the image carrier 9 is fixed by the fixing device 15 . After the toner image has been fixed on one side of the sheet S, the sheet ejection/double-sided switching flapper 62 is selectively switched by blocking the fixed sheet ejection sensor 61. Now, when double-sided printing is specified, the paper S is placed in the paper output/duplex switching flapper 62
By blocking the reversal sensor 73, the sheet S is guided to the reversing guide 75 side by controlling the rotational direction of the reversing roller pair 72 and the switching timing during reversing.

When the rear end of the paper S is positioned in front of the reversing roller pair 72, the reversing roller pair 72 reverses, so that the paper S is guided to the reversing conveyance path 76 and conveyed to the refeeding unit 77.19 Registration Regulation Guide 80.81 waits at a position wider than the maximum paper width of the paper S before entering the paper S. After the paper S printed on one side passes through the first conveyance roller pair 79 under pressure with the pressure roller 79b and enters between the lateral registration regulation guides so and si, it intercepts the paper detection sensor 85, and then passes through the paper refeeding guide member. It stops at a position a certain amount ahead of 84.

Next, the first. By the action of the second pressure rollers 79b, 83b or a drive mechanism (not shown), the first pressure roller 79b, 83b is pressed. The paper S is separated from the 279a and 83a to be in a free state. In this state, the lateral registration regulation guides 80 and 81 move toward each other and stop at a predetermined paper width position to adjust the lateral registration of the paper S. And the first. Second pressure rollers 79b, 83
By applying pressure again to drive the first conveying roller pair 79 and paper refeeding guide member 84, the sheet S is conveyed to the registration rollers 7, and an image is printed on the back side thereof.

In addition, in the above configuration, the upper part of the reversing unit 70 is
The reversing unit 70 is attached to and detached from the main body 2 by a latch (not shown), and by removing the latch, the reversing unit 70 can be opened in the direction of the arrow as shown in FIG. Further, the refeeding unit 77 is pulled out from the double-sided frame 69 by being guided by the rail 69a as shown in FIG. 3 by extending the handle 77a as described above. At this time of withdrawal, the refeeding unit 77
When the re-feeding unit 77 is partially pulled out, the protrusion 90a of the pull-out regulating lever 90 or the stopper 26a of the main frame 26 stops the re-feeding unit 77 from being extended.

Furthermore, as shown in FIG. 4, when the user presses the withdrawal regulating lever 90, the protrusion 90a
The refeeding unit 77 can be completely removed from the double-sided frame 69 by being disengaged from the stopper 26a. Further, as shown in FIGS. 5 and 6, the positioning protrusion 96 of the apparatus main body 2 is inserted into the positioning hole 97 of the double-sided frame 69.
By fitting the latches 100 of the double-sided frame 69 into the engaging holes 1 of the main body frame 26, the double-sided frame 69 and the device main body 2 are accurately positioned.
06, the positioning protrusion 96 and the device main body 2 are connected.

This connection is released by moving the knob 102a of the link 102 rearward to the release side.

As described above, when the paper S jams on the duplex side, the jammed paper can be removed by opening the reversing unit 70 as shown in FIG. 5 and pulling out the refeeding unit 77 from the duplex frame 69. S can be easily taken out.

In addition, the reversing unit 70. Since the double-sided sides of the refeed unit 77 and double-sided frame 69 are configured to be detachable from the apparatus main body 2, it is possible to manufacture the apparatus main body 2 side and the double-sided frame 69 side by different manufacturers. By making the connection, it becomes easy to configure the image forming apparatus, and maintenance efficiency such as parts replacement and repair is improved.

Next, a second embodiment of the present invention will be described based on FIG. 9. Components that are the same as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In the figure, the reversing unit 121 in this embodiment has a slider 122 at the bottom.

Inside the double-sided frame 69, there is a guide member 123 that slidably supports the slider 122, and a guide member 123 that supports the slider 122 in a slidable manner.
A stopper 125 is provided for regulating the movement of the parts 2 and 2, respectively. A protrusion 126 is fixed to the free end of the slider 122, and when the reversing unit 121 is pulled out to the limit position as shown in the figure, it comes into contact with the stopper 125 to restrict the movement of the reversing unit 121 from being pulled out.

Further, the refeeding unit 77 can be pulled out as shown in the figure in the same manner as in the first embodiment. As described above, the reversing unit 121 and the refeeding unit 77
By pulling out the paper S from the main body 2 of the apparatus, it is possible to easily remove the jammed paper S on both sides and perform maintenance.

Next, a third embodiment of the present invention will be explained with reference to FIG.

In the figure, a reversing section 131 including a paper ejection/duplex switching flapper 62, a pair of reversing rollers 72, etc. is a double-sided frame 6
It is constructed integrally with 9. A guide plate 132 forming a reversing conveyance path 76 is disposed behind the reversing unit 131, and its base is connected to the double-sided frame 6 by a support shaft 133.
It is pivoted to 9. Further, a slider 135 is provided on the double-sided frame 69, and the main body frame 26 of the apparatus main body 2 supports the slider 135 so that the slider 135 can be slid in the front-rear direction. By configuring this embodiment as described above, the reversing unit 131 and the double-sided frame 6
Removal of the jammed paper S on both sides of the paper sheet S, etc., and maintenance can be easily performed.

11 and 12 show a fourth embodiment of the invention.

In the figure, a reversing unit 141 having a reversing roller pair 72 is connected to a reversing guide 14 that forms an introduction bath after reversing.
2 and a guide surface 143 forming a reversing conveyance path 76, the base of which is connected to a double-sided frame 69 by a support shaft 145.
It is pivoted to.

Further, the guide unit 146 is provided with a paper discharge/duplex switching flapper 62, a reversal sensor 73, etc., and the base of the guide unit 146 is also connected to the reversing unit 141.
It is pivotally connected to the double-sided frame 69 by a support shaft 145 that is coaxial with the base of the frame.

The side edge of the guide unit 146 on the apparatus main body 2 side forms a paper discharge guide 147, and the outer side edge forms a guide surface 149 of the introduction path after reversal and a guide surface 1 of the reversal conveyance path 76.
50 respectively.

By selectively rotating one or both of these units 141 and 146, the paper ejection bus to the paper ejection tray 67, the introduction path after reversal, and the reversal conveyance path 76 to the refeed unit 77 can be Since the paper S is opened, the jammed paper S can be removed more easily.

(G) As described in detail, the present invention has the following effects.

(1) Since the reversing unit and refeeding unit can be assembled independently from the main body of the apparatus, it is easy to set up a duplex machine for double-sided recording.

(2) Since the reversing unit and refeeding unit can be made independent from the main body of the machine, even after the user has purchased the main body of the machine, the user can purchase the reversing unit and refeeding unit as options. It is possible to install it on.

(3) Since the reversing unit and refeeding unit are movable independently with respect to the main body of the apparatus, jam removal and maintenance in the reversing unit and refeeding unit are facilitated, and the reversing unit and refeeding unit are movable independently. Even if the feeding unit requires repair, it is possible to use the main body of the apparatus for forming images on one side.

(4) Furthermore, by making the refeeding unit retractable from the double-sided frame, there is no need to provide maintenance space required for jam clearance in conventional devices, making the image forming device more compact. I have something to do.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view of an image forming apparatus showing a first embodiment of the present invention, FIG. 2 is a plan view thereof, and FIGS. FIGS. 5 and 6 are vertical side views of the joint between the double-sided frame and the device body, FIG. 7 is a front view, FIG. 8 is a vertical front view, and FIG. 9 is a vertical side view of the state. A tenth vertical cross-sectional side view of an image forming apparatus showing a second embodiment of the present invention.
11 is a vertical sectional side view of an image forming apparatus showing a fourth embodiment of the invention, FIG. 12 is an operational diagram, FIG. 13 is a longitudinal sectional side view of an image forming apparatus showing an example of a conventional image forming apparatus, and FIG. 14 is a longitudinal sectional side view of another conventional image forming apparatus. S... Paper 2... Apparatus main body, 9... Image carrier, 15... Fixing device, 26a... Stopper, 62... Paper discharge/duplex switching flapper (switching means), 69.・Double-sided frame 70...
Reversing unit, 72...Reversing roller pair (reversing rotation means), 75... Reversing guide 76... Reversing conveyance path 77... Re-feeding unit, 90... Pull-out regulation lever, 100... latch, 106
...Engagement hole, 121,131.141...Reversing unit

Claims (1)

[Scope of Claims] 1. An image formed on an image bearing member in an apparatus main body is transferred to a sheet of paper, and the sheet is conveyed by selectively switching the conveying direction of the sheet after being fixed by a fixing device by a switching means. In an image forming apparatus that performs single-sided recording or double-sided recording, the apparatus main body has a removable double-sided frame, and a reversing rotation means and a reversing conveyance path for guiding the paper branched and conveyed by the switching means to the double-sided frame. a reversing unit mounted on the double-sided frame so as to be able to open and close with respect to the apparatus main body; and a reversing unit capable of refeeding paper conveyed from the reversing unit to the image carrier; An image forming apparatus comprising: a refeeding unit disposed within the double-sided frame so as to be freely drawn out from the double-sided frame. 2. The image forming apparatus according to claim 1, wherein the duplex unit is provided with a stopper for stopping the refeeding unit at a predetermined position when the refeeding unit is pulled out. 3. The image forming apparatus according to claim 1, wherein the refeeding unit is detachable from the duplex unit by releasing the stop operation of the stopper using a release mechanism.