JPH08188344A - Image forming device and double faces carrier device - Google Patents

Abstract

PURPOSE: To fit a double faces carrier device without removing a rear opening and closing door from an image forming device body when the optional double faces carrier device is mounted. CONSTITUTION: An engaging part 47 with which a finger 46A of a latch 46 of a vertical part 22A which is an opening and closing part of a double faces carrier device 22 is mounted in a rear opening and closing door 18. Thus, the vertical part 22A is coupled to an image forming device body 19 by engaging the finger 46A of the latch 46 with the engaging part 47 of the rear opening and closing door 18 without removing the rear opening and closing door 18 from the image forming device body 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a facsimile and a copying machine, and a double-sided conveying apparatus optionally provided outside the main body of the image forming apparatus of the image forming apparatus.

[0002]

2. Description of the Related Art Some small-sized image forming apparatuses such as printers, facsimiles, and copying machines are capable of double-sided image formation by installing an optional double-sided conveyance device outside the main body of the image forming apparatus. is there.

The double-sided conveying device referred to here is an image forming device which reverses a sheet discharged outside the main body of the image forming apparatus with the image forming surface facing upward after finishing the image formation on the first surface. The apparatus has a function of conveying a sheet with the apparatus surface downward to the image forming unit in the image forming apparatus body again.

FIG. 4 shows the overall structure of a conventional small-sized image forming apparatus (laser beam printer) capable of double-sided image formation by equipping an optional double-sided conveying device.

Here, the overall configuration of the image forming apparatus will be described along the flow of the sheets S fed from the paper feed cassette 1.

The sheets S stacked and stored in the sheet feeding cassette 1 are sequentially fed out from the uppermost sheet by a half-moon shaped sheet feeding roll 2 which makes one rotation counterclockwise from the position shown in the figure. Of the fed-out sheet S, only the uppermost sheet is separated into one sheet by a separation claw (not shown) provided at the front end of the sheet feeding cassette 1 and is sent to the conveying roller pair 3.

When the conveying roller pair 3 conveys the sheet S until the leading edge of the sheet hits the nip of the registration roller pair 4 whose rotation is stopped and a predetermined loop is formed on the sheet S, the conveying roller pair 3 stops rotating once. By forming this loop,
The skewed state of the sheet S is corrected.

The sheet S whose skewed state has been corrected is rotated by the registration roller pair 4 which starts rotation at a timing of aligning the position of the toner image on the photosensitive drum 5 rotating clockwise with the leading edge of the sheet. , To the transfer section between the photosensitive drum 5 and the transfer roll 6. At this time, the conveyance roller pair 3 that has stopped rotating rotates in synchronization with the registration roller pair 4 until the trailing edge of the sheet passes through the nip.

The photosensitive drum 5 rotating clockwise.
The toner image on the photosensitive drum 5 is sequentially transferred by the transfer roll 6 onto the sheet S passing through the nip of the transfer roller 6 rotating counterclockwise. A toner image is formed on the photosensitive drum 5 rotating in the clockwise direction as follows. That is, the laser scanner 7 irradiates the photosensitive drum 5 with the laser beam L based on the information sent from the external computer. As a result, an electrostatic latent image is formed on the uniformly charged photosensitive drum 5, and this electrostatic latent image is supplied from a developing device (not shown) installed downstream of the laser light irradiation position. Visible toner (toner image).

The sheet S after the transfer of the toner image at the transfer portion is sent to the fixing roller pair 8 and, while passing through the nip of the identification fixing roller pair 8, is overheated by the fixing roller 8A and by the pressure roller 8B. By applying pressure, the transferred toner image is fixed on the sheet surface.

The sheet S passing through the fixing roller pair 8 is sent to the discharge roller pair 10 by the conveying roller pair 9, and is discharged facedown onto the discharge tray 11 outside the apparatus by the discharge roller 10.

The reference numeral 12 in FIG. 4 indicates the paper feed cassette 1.
Reference numeral 13 is a path for guiding the sheet S fed from the sheet to the conveying roller pair 3, and reference numeral 13 is a path for guiding the sheet S conveyed by the conveying roller 3 to the registration roller pair 4.
Reference numeral 4 is a path for guiding the sheet S conveyed by the registration roller pair 4 to the transfer portion, and reference numeral 15 is a path for guiding the sheet S passing through the nip between the photosensitive drum 5 and the transfer roll 6 to the fixing roller pair 8. Reference numeral 16 is a path for guiding the sheet S passing through the nip of the fixing roller pair 8 to the conveying roller pair 9, and reference numeral 17 is a path for guiding the sheet S conveyed by the conveying roller pair 9 to the discharge roller pair 10.

In this image forming apparatus, a rear opening / closing door 18 for jam clearance, parts replacement, etc. is provided on the rear surface portion 19A of the image forming apparatus main body 19. This rear door 1
The reference numeral 8 is attached to the image forming apparatus main body 19 so as to be rotatable in a vertical direction about a support shaft (hinge pin) 20. When the rear opening / closing door 18 is closed (the upper state shown by the solid line), the latch 21 at the front end of the door is engaged with the image forming apparatus main body 19. Further, when the rear opening / closing door 18 is opened to perform a jam process or the like (upper side in the imaginary line), the latch 21 engaged with the image forming apparatus main body 19 is removed from the image forming apparatus main body 19 and is omitted. Tilt it down until it is level.

When this image forming apparatus is equipped with an optional double-sided conveying device, conventionally, the image forming apparatus main body 19 is used.
The rear opening / closing door 18 is removed from the. Rear opening / closing door 18
Can be removed from the image forming apparatus main body 19 by pulling out the support shaft 20 from the image forming apparatus main body 19.

FIG. 5 shows a state in which the image forming apparatus main body 19 from which the rear opening / closing door 18 is removed is equipped with the conventional double-sided conveying device 22.

The double-sided transport device 22 includes a vertical portion (reversing function portion) 22A located at the rear portion of the image forming apparatus main body 19,
The image forming apparatus main body 19 includes a horizontal portion (circulation function portion) 22B located below the main body 19. The vertical portion 22A has a first
A portion having a function of reversing the sheet S discharged to the outside of the image forming apparatus main body 19 after finishing the image formation on the surface,
The horizontal portion 22B is a portion having a function of transporting the sheet S reversed by the vertical portion 22A to the transfer portion with the image forming surface facing downward.

The vertical portion 22A is different from the horizontal portion 22B in
The support shafts (hinge pins) 23 are coupled so as to be rotatable in the vertical direction.

The image forming apparatus main body 19 has a double-sided conveyance device 2
When setting 2, the image forming apparatus main body 19 is first placed on the horizontal portion 22B. Then, the vertical portion 2 is formed on the rear surface portion 19A of the image forming apparatus main body 19 placed on the horizontal portion 22B.
2A butts the latch 24 to the image forming apparatus main body 19
To be engaged. In this case, a part 25 of the vertical portion 22A is fitted in the recess 26 for the rear opening / closing door, so that the double-sided conveying device 22 is positioned with respect to the image forming apparatus main body 19. Also, the latch 24 is removed from the rear opening / closing door 1
The latch 24 of FIG.

Next, the flow of the sheet S in the double-sided image forming mode in the present image forming apparatus equipped with the double-sided conveying device 22 will be described.

When the double-sided image forming mode is designated, the flapper 27 arranged immediately downstream of the fixing roller pair 8 is closed toward the discharge tray 11 and the path 28 is opened toward the double-sided conveying device 22. Is switched to the position shown by the dotted line. Therefore, the sheet S which has completed the image formation on the first surface and has passed the fixing roller pair 8 is fed into the double-sided transport device 22 through the path 28. The flapper 27 is located on the double-sided conveyance device 22 side, and is installed so as to be rotatable in the up-down direction about the support shaft 27A.

The sheet S sent to the path 29 through the path 28 reaches the reversing roller pair 31 which is rotating forward while moving the flapper 30 closing the path 29 to the position shown by the dotted line. The flapper 30, which is rotatable in the vertical direction about the support shaft 30A, is a coil spring 3 having a small spring force.
Because it is biased clockwise by 2
By the force of the sheet S that moves the sheet 9, the sheet 9 rotates counterclockwise while resisting the spring force of the coil spring 32.

The sheet S conveyed to the pair of reversing rollers 31 rotating in the forward direction is sent out of the double-sided conveying device 22 through the path 33. Then, when the trailing edge of the sheet S passes through the flapper 30, the pair of reversing rollers 31 reversely rotates, so that the sheet S once fed out of the double-sided transport device 22 moves to the path 34 with the trailing edge as the leading edge. Sent in.

While the sheet S is moving on the path 29, the light shielding portion 30A of the flapper 30 which is moving to the position shown by the dotted line shields the light of the photo interrupter 35, but the rear end of the sheet S passes through the flapper 30. Then, the flapper 30 is returned to the position shown by the solid line by the restoring force of the compressed coil spring 32, and the light blocking portion 30A does not block the light of the photo interrupter 35. Therefore, the photo interrupter 35 outputs an ON signal, and the reversing roller pair 31 is output based on this ON signal.
The rotation direction of is switched from forward rotation to reverse rotation.

The sheet S sent to the path 34 is sent to the path 37 of the horizontal portion 22B by the pair of carrying rollers 36. Then, the sheet S sent to the path 37 is carried by the carrying roller pairs 38, 39, 40 and again sent to the registration roller pair 4. In this case, the conveyance roller pair 40
The sheet S having passed through passes through the paths 41 and 42 and reaches the conveying roller pair 3 upstream of the registration roller pair 4. The path 41 is formed in the paper feed cassette 1.

As described above, in the present image forming apparatus equipped with the double-sided conveying device 22, for example, parts inside the image forming apparatus main body 19 are replaced, or a jam occurs from the path 28 to the path 29. In this case, the latch 24 is removed from the image forming apparatus main body 19 and the vertical portion 22A is opened as shown by a dotted line to perform parts replacement, jam processing, and the like.

In the image forming apparatus of the conventional example described above, only face-down sheet ejection can be performed, but in the image forming apparatus of another conventional example shown in FIG. 6, both face-up sheet ejection and face-down sheet ejection are possible. It has become.

In this image forming apparatus, when face-up sheet discharge is to be performed, the face-up tray 43 provided on the rear opening / closing door (hatched portion) 18 is opened as shown by the dotted line. When face-down sheet discharge is to be performed, the face-up tray 43 is closed as shown by the solid line.

When the face-up tray 43 is opened, the flapper 44 arranged immediately downstream of the fixing roller pair 8 (mounted on the rear opening / closing door 18) pushes up the face-up tray 43. It is pushed up by the portion 43A to close the path 16 as shown by the dotted line. Therefore, the image-formed sheet S that has passed the fixing roller pair 8 is discharged onto the face-up tray 43 from the discharge port 45 with the image forming surface facing upward.

When the face-up tray 43 is closed, the flapper 44 opens the return path 16 to the position shown by the solid line by the return spring (not shown). Therefore, the image-formed sheet S that has passed the fixing roller pair 8 is discharged onto the discharge tray 11 with the image forming surface facing downward.

The face-up tray 43 is rotatable about the support shaft 43B, and the flapper 4
4 is rotatable about a support shaft 44A.

[0031]

However, in the case of the above-mentioned conventional image forming apparatus (FIGS. 4 and 6), firstly, the image forming apparatus main body 19 is required to be equipped with the optional double-sided conveying device 22. The rear opening / closing door 18 must be removed,
Further, the removed rear opening / closing door 18 must be stored so as not to damage it. Secondly, when the image forming apparatus of FIG. 6 is equipped with the conventional double-sided conveyance device 22, face-up sheet ejection cannot be performed. There were problems such as.

Therefore, the present invention has been made in view of the above circumstances, and an image forming apparatus capable of being equipped with an optional double-sided conveyance device without removing the rear opening / closing door from the image forming apparatus main body, and An object of the present invention is to provide a double-sided conveyance device that enables face-up paper ejection of the image forming apparatus.

[0033]

According to a first aspect of the present invention, the image forming apparatus main body (19) is provided with a rear opening / closing door (18) for performing jam processing and the like, and double-sided image formation is performed. The present invention relates to an image forming apparatus that can be provided with a separate double-sided conveying device (22) outside the image forming apparatus main body (19).

In order to achieve the above-mentioned object, the invention according to claim 1 engages with the engagement / disengagement means (46) of the opening / closing part (22A) of the double-sided transfer device (22). A joint portion (47) is provided on the rear opening / closing door (18).

The invention described in claim 6 relates to a double-sided conveyance device detachably provided outside the image forming apparatus main body (19) to enable double-sided image formation in the image forming apparatus.

In order to achieve the above object, the invention according to claim 6 places the image-formed sheet (S) on which the image has been formed in the image forming apparatus main body (19) with the image forming surface facing upward. Discharge stacking means (5
2) is included.

[0037]

According to the invention of claim 1 having the above-mentioned structure,
The engaging / disengaging means (46) of the opening / closing part (22A) is attached to the rear opening / closing door (1
When engaged with the engaging part (47) of 8), the opening / closing part (22)
A) can be connected to the image forming apparatus main body (19).

As a result, it becomes possible to provide the double-sided conveying device (22) without removing the rear opening / closing door (18) from the image forming apparatus main body (19), and the image forming apparatus of the double-sided conveying device (22). It can be easily set on the main body (19), and since there is no need to remove the rear opening / closing door (18) for storage, the rear opening / closing door (18) will not be damaged during storage.

According to the sixth aspect of the present invention having the above-mentioned structure, the image-formed sheet (S) on which image formation has been completed in the image forming apparatus main body (19) is imaged on the discharged sheet stacking means (52). The paper can be discharged with the forming surface facing upward.

This eliminates the problem that the face-up sheet discharge mode is disabled because the double-sided transport device (22) is installed.

The reference numerals in parentheses refer to the drawings and do not limit the structure of the present invention.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 shows the overall configuration of an image forming apparatus (laser beam printer) and a double-sided conveyance device according to Embodiment 1 of the present invention.

In describing the structures of the image forming apparatus and the double-sided conveying device, the same members and the like as those of the conventional image forming apparatus (FIGS. 4 and 6) and the double-sided conveying device (FIG. 5) are used. Are denoted by the same reference numerals, and the description of those that are structurally and functionally unchanged will be omitted.

In this image forming apparatus, an optional double-sided conveying device 22 can be installed without removing the rear opening / closing door (hatched portion) 18 from the image forming apparatus main body 19. This is an engaging portion 47 with which a claw (engaging / disengaging portion) 46A of a latch (engaging / disengaging means) 46 of a vertical portion (opening / closing portion) 22A that can be opened / closed around the support shaft 23 is engaged.
Is provided on the rear opening / closing door 18.

The latch 46 of the vertical portion 22A is movable in the vertical direction and is biased upward by the coil spring 48. FIG. 1 shows a state in which the latch 46 is biased by the coil spring 48 and the claw 46A is engaged with the engaging portion 47 of the rear opening / closing door 18 (locked state). When the latch 46 in this state is pushed in the direction of the arrow against the spring force of the coil spring 48, the pawl 46 disengages from the engaging portion 47 (releases the locked state), and the vertical portion 22A can be opened.

The latch 49 of the rear opening / closing door 18 is movable in the vertical direction and is biased upward by the coil spring 50. In FIG. 1, the latch 49 is a coil spring 50.
The state (locked state) in which the claw 49A is engaged with the engaging portion 19A of the image forming apparatus main body 19 by being urged by is shown. When the latch 49 in this state is pushed in the direction of the arrow against the spring force of the coil spring 50, the claw 49A will engage with the engaging portion 1.
The rear opening / closing door 18 can be opened by disengaging from 9A (unlocking state).

As described above, the vertical portion 22A can be opened independently by pushing the latch 46 in the arrow direction. However, in this embodiment, when the latch 49 is pushed in the arrow direction to open the rear opening / closing door 18, The vertical portion 22A is adapted to open in an interlocking manner. That is, when the latch 49 is pushed in the direction of the arrow, the lower end 49B of the latch 49 is moved to the pawl 46 of the latch 46.
Pushing A in the arrow direction releases the engagement state with the engagement portion 47.

Therefore, in the case of carrying out jam processing or parts replacement, the rear opening / closing door 18 and the vertical portion 22A can be opened by a one-touch operation by merely pushing the latch 49 in the direction of the arrow.

A flapper 44 arranged immediately downstream of the fixing roller pair 8 of the present image forming apparatus (here, installed in the image forming apparatus main body 19) is an arm member installed on the vertical portion 22A side. It can be switched by 51. The arm member 51 is driven by an electromagnetic solenoid (not shown). When the solenoid is off, the arm member 51 is in the position shown by the solid line. When the solenoid is turned on, the arm member 51 rotates counterclockwise around the support shaft 51A to the position shown by the dotted line. Moving. By this movement of the arm member 51, the flapper 44 located at the position shown by the solid line is pushed up to the position shown by the dotted line to close the path 16. On the other hand, when the solenoid is turned off, the arm member 51 and the flapper 44 are urged by the respective coil springs to return to the positions shown by the solid lines, and the path 16 is opened.

C for controlling the overall operation of the image forming apparatus
The PU (not shown) controls the electromagnetic solenoid that drives the flapper 44 to be turned on when the face-up sheet discharge mode and the double-sided image forming mode are designated.
Further, when the face-down sheet discharge mode is designated, the electromagnetic solenoid is controlled to be turned off.

In the vertical portion 22A of the double-sided transport device 22,
A face-up tray (paper discharge stacking unit) 52 for discharging and stacking the image-formed sheets S that have passed through the transport roller pair 31 in the face-up discharge mode, and an image-formed sheet S that has passed through the transport roller pair 31. A relay tray (relay stacking means) 53 for relaying the sheet to the face-up tray 52. The face-up tray 52 is attached to the main body of the vertical portion 22A so as to be rotatable in the up-down direction about the support shaft 52A. The relay tray 53 is mounted on the roller shaft 31A of the lower roller of the transport roller pair 31 so as to be rotatable in the up-down direction about the roller shaft 31A.

When face-up sheet discharge is performed, the face-up tray 52, which was closed at the position shown by the dotted line, is opened at the position shown by the solid line. At this time, the light shielding portion 52B of the face-up tray 52 comes to shield the light of the photo interrupter (detection means) 54, and the photo interrupter 54 outputs an OFF signal to the CPU. CPU
When an off signal is input from the photo interrupter 54,
Set the face-up paper ejection mode. When the face-up tray 52 is opened, the relay tray 53 located at the position shown by the dotted line rotates counterclockwise by its own weight to move to the position shown by the solid line, and is substantially parallel to the face-up tray 52. It becomes a state.

The pair of transport rollers 31 for transporting the image-formed sheet S in the face-up discharge mode is rotated forward until the trailing edge of the sheet passes through the nip and is discharged onto the face-up tray 52 and the relay tray 53. Continue.

When performing double-sided image formation, the face-up tray 52 that was open at the position shown by the solid line is closed at the position shown by the dotted line. At this time, the light blocking portion 52B of the face-up tray 52 does not block the light of the photo interrupter 54.
The ON signal is output to. CPU is photo interrupter 5
When an ON signal is input from 4, the double-sided image forming mode is set. When the face-up tray 52 is closed, the relay tray 53 located at the position shown by the solid line is pushed up by the face-up tray 52 and moved to the position shown by the dotted line.

The sheet S that has passed the pair of conveying rollers 31 in the double-sided image forming mode has the relay tray 53 and the face-up tray 52 until the trailing edge of the sheet passes the flapper 30.
It is sent to the path 55 formed by and.

As described above, in this embodiment, the face-up paper ejection mode can be established by opening the face-up tray 52 with the operator's hand, and the double-sided image forming mode can be established by closing the face-up tray 52. You can specify. When the face-down paper discharge mode is designated, a designation key provided on the operation panel (not shown) is pressed.

As shown in FIG. 1, when the image forming apparatus main body 1 is equipped with an optional double-sided conveying device 22, the face-up tray 52 is mounted on the double-sided conveying device 22 side. However, when the image forming apparatus main body 19 is not provided with the double-sided conveying device 22, the double-sided conveying device 22 is mounted on the rear opening / closing door 18 side to enable face-up sheet ejection.
In this case, the face-up tray 52 is the rear opening / closing door 1.
It is attached to 8 so as to be rotatable in the up-and-down direction around the support shaft 52A.

The face-up tray 52 mounted on the rear opening / closing door 18 is used for face-down sheet discharge.
When the face-up tray 52 is opened, the face-up tray 52 is opened when the face-up paper is discharged.
The flapper 4 whose light-shielding portion 52B was at the position shown by the solid line
4 is pushed up to the position shown by the dotted line, and the flapper 44 closes the path 16. When the face-up tray 52 is closed, the flapper 44 located at the position shown by the dotted line is urged by the coil spring to return to the position shown by the solid line, and the flapper 4
4 opens path 16.

In this way, the face-up tray 52
Is attached to the rear opening / closing door 18 side, the face-up tray 52 can be opened to select the face-up discharge mode.
When is closed, the face-down paper discharge mode can be selected. <Embodiment 2> This embodiment shown in FIGS. 2 and 3 shows a configuration in which the relay tray 53 of Embodiment 1 is interlocked with the opening / closing operation of the face-up tray 52 via an interlocking mechanism (interlocking means) 56. .

The interlocking mechanism 56 comprises a slide rod member 57 arranged on the face-up tray 52 side, a cam member 58 arranged on the relay tray 53 side, and the like.

The slide rod member 57 is slidably fitted in a guide hole 59 formed in the main body of the vertical portion 22A. The cam member 58 is attached to the main body of the vertical portion 22A so as to be rotatable in the up-down direction about a support shaft 60. The cam member 58 is biased counterclockwise by the coil spring 61.

FIG. 2 shows a state in which double-sided image formation is performed. In this case, the face-up tray 52
Is closed at the position shown (a substantially vertical position). At this time, the cam member 58, which is biased counterclockwise by the coil spring 61, has its projection 58A abutted against the restricting portion 62 and is restricted in rotation. The relay tray 53 is pushed up to the illustrated position by the cam member 58 in this state.

The sheet S that has passed the pair of conveying rollers 31 in the double-sided image forming mode is conveyed to the path 55 formed by the face-up tray 52 which is closed and the relay tray 53 which is pushed up.

FIG. 3 shows a state in which face-up sheet discharge is performed. In this case, the face-up tray 52 is opened at the illustrated position (position close to horizontal). When the face-up tray 52 that has been closed as shown in FIG. 2 is opened, the base end 52C of the face-up tray 52 moves the slide rod member 57 to the right (the direction of the arrow).
Slide to. Then, the slid slide rod member 57 presses the protruding portion 58A that is in contact with the regulation portion 62 to rotate the cam member 58 in the clockwise direction. As a result, the relay tray 5 pushed up by the cam member 58
3 follows its cam member 58 by its own weight and descends to a position shown in the figure which is substantially parallel to the face-up tray 52.

When the face-up tray 52 which is opened as shown in FIG. 3 is closed, the base end 52C of the face-up tray 52 is separated from the slide rod member 57, and the slide rod member 57 is in a freely slidable state. Therefore, the cam member 58 is biased by the compressed coil spring 61, and rotates in the counterclockwise direction until the protruding portion 58A comes into contact with the regulation portion 62. The relay tray 53 is pushed up by the cam member 58 that rotates counterclockwise.

[0066]

As described above, in the image forming apparatus of the present invention, the rear opening / closing door is provided with the engaging portion for engaging the engaging / disengaging means of the opening / closing portion of the double-sided conveying device.
It is possible to set the double-sided conveyance device in the image forming apparatus main body without removing the rear opening / closing door from the image forming apparatus main body.

Further, in the double-sided conveying device of the present invention, a paper discharge stacking means for discharging and stacking the image-formed sheets whose images have been formed in the main body of the image forming device with the image forming surface facing upward. Therefore, the image forming apparatus having the double-sided conveying device of the present invention can perform face-up sheet ejection.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an overall configuration of an image forming apparatus (laser beam printer) and a double-sided conveyance device according to a first embodiment of the present invention.

FIG. 2 is a configuration of an interlocking mechanism for interlocking a relay tray with an opening / closing operation of a face-up tray provided in the double-sided conveyance device (Example 2), and an operation when the face-up tray is closed. FIG.

FIG. 3 is a vertical cross-sectional side view for explaining an operation when the face-up tray is opened.

FIG. 4 is a vertical sectional side view showing the overall configuration of a conventional image forming apparatus (laser beam printer).

FIG. 5 is a vertical cross-sectional side view showing the overall configuration of a conventional image forming apparatus including an optional double-sided conveyance device.

FIG. 6 is a vertical cross-sectional side view showing the overall configuration of another conventional image forming apparatus (laser beam printer).

[Explanation of symbols]

 18 Rear Opening / Closing Door 19 Image Forming Apparatus Main Body 22 Double-sided Conveying Device 22A Vertical Section (Opening / Closing Section) 31 Reverse Roller Pair 31A Roller Shaft 46,49 Latch (Disengagement Means) 46A Claw (Disengagement Section) 47 Engagement Section 52 Face Up tray (paper discharge stacking means) 52A Spindle 53 Relay tray (relay stacking means) 54 Photo interrupter (detecting means) 56 Interlocking mechanism (interlocking means) S sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 21/00 510

Claims (13)

[Claims] 1. A rear opening / closing door for performing jam processing and the like is provided in the image forming apparatus main body, and a separate double-sided conveying device for performing double-sided image formation is provided outside the image forming apparatus main body. In the image forming apparatus capable of achieving the above, the image forming apparatus is characterized in that the rear opening / closing door is provided with an engaging portion for engaging with the engaging / disengaging means of the opening / closing portion of the double-sided conveying device. 2. The engagement / disengagement means of the opening / closing part engaging with the engagement part of the rear opening / closing door is interlocked with the operation of releasing the engagement / disengagement means of the rear opening / closing door. The image forming apparatus according to claim 1, wherein the engagement state with the mating portion is released. 3. The engagement / disengagement means of the opening / closing part and the engagement / disengagement means of the rear opening / closing door can be engaged / disengaged with respect to the respective engaging parts by moving in the same direction, and the engagement / disengagement of the rear opening / closing door. The image forming apparatus according to claim 1, wherein the engagement / disengagement portion of the engagement / disengagement means of the opening / closing portion is located ahead of the disengagement means in the disengagement movement direction. 4. A paper discharge stacking device for discharging and stacking image-formed sheets with an image forming surface facing upward is detachably attached to the rear opening / closing door. 1. The image forming apparatus according to 1. 5. When the double-sided conveying device is provided in the image forming apparatus main body, the discharged sheet stacking means is detached from the rear opening / closing door and detachably attached to a predetermined position of the double-sided conveying device. The image forming apparatus according to claim 4. 6. A double-sided conveyance device detachably provided outside the main body of the image forming apparatus to enable double-sided image formation in the image forming apparatus, wherein an image has been formed in the main body of the image forming apparatus. A double-sided conveyance device comprising a sheet discharge stacking unit for stacking discharged sheets with the image forming surface facing upward. 7. The discharged sheet stacking means is detachably attached to a rear opening / closing door of the image forming apparatus main body for discharging and stacking image-formed sheets with an image forming surface facing upward. 7. The double-sided transfer device according to claim 6, which is a loading means. 8. The double-sided paper according to claim 6, wherein the discharged paper stacking means is attached so as to be rotatable in a vertical direction about a support shaft and can be set in an open position and a closed position. Carrier device. 9. The apparatus according to claim 8, wherein when the discharged sheet stacking means is set to the closed position, the discharged sheet stacking state is set, and when the discharged sheet stacking means is set to the closed position, the sheet is inverted. Double-sided transfer device. 10. The control of the image forming apparatus main body when it is detected whether or not the discharged paper stacking means is set at a closed position, and when it is detected that the discharged paper stacking means is set at a closed position. A signal for designating the face-up paper discharge mode is output to the means, and when it is detected that the paper discharge stacking means is not set to the closed position, the double-sided image forming mode is specified to the control means. The double-sided conveyance device according to claim 9, further comprising a detection unit that outputs a signal. 11. A vertical direction about a roll axis of a lower roll of the reversing roller pair, between the reversing roller pair for reversing the sheet fed from the inside of the image forming apparatus main body and the discharged sheet stacking means. 10. The double-sided conveyance device according to claim 9, further comprising a rotatable and intermediate loading device. 12. The relay stacking means is interlocked with the opening / closing operation of the discharged paper stacking means, and when the discharged paper stacking means is set to a closed position, the relay stacking means is in a stacking state and the discharged paper stacking means is closed. 12. The double-sided conveyance device according to claim 11, wherein the double-sided conveyance device is in a posture of reversing when set to the open position. 13. The double-sided conveyance device according to claim 12, wherein the relay stacking means is interlocked with the opening / closing operation of the discharged paper stacking means via interlocking means.