Resupplying apparatus and image forming apparatus

This invention relates to a resupplying apparatus detachably attached to an image forming apparatus body which comprise a resupplying passage connecting a sheet material passage on a downstream side of an image forming means in the image forming apparatus body with another sheet material passage on an upstream side of the image forming means. Also, the resupplying apparatus comprises switchback conveying means placed in the resupplying passage for reversing the conveyance direction of the sheet material upon reception of the sheet material from a conveyer in the image forming apparatus body, said switchback conveying means at least partially assembled in the image forming apparatus body; and resupplying means for returning the sheet material to the upstream side of the image forming means through the resupplying passage.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a resupplying apparatus and an image forming 
apparatus and, more particularly, to a resupplying apparatus detachably 
attached to an image forming apparatus such as an electrophotographic 
apparatus, an electrostatic recording apparatus, and a laser printer and 
to an image forming apparatus equipped with such a resupplying apparatus. 
2. Description of Related Art 
A conventional resupplying apparatus assembled to an image forming 
apparatus such as a laser printer has a mechanism in which a sheet 
material is resupplied to an image forming section of the image forming 
apparatus by switchback conveyance, or by reversing the conveying 
direction, of the sheet material to produce recording on one side of the 
sheet material after recording is made on the other side. Many of those 
are already made as products and actually used. 
SUMMARY OF THE INVENTION 
This invention is an improvement based on the conventional resupplying 
apparatus. It is an object of the invention to provide a resupplying 
apparatus that can be made smaller and more compact with reduced costs and 
be operated with lower noise, as well as readily handled by users. 
A representative constitution of the invention, to accomplish the foregoing 
object, is characterized in a resupplying apparatus detachably attached to 
an image forming apparatus body, including: a resupplying passage 
connecting a sheet material passage on a downstream side of an image 
forming means in the image forming apparatus body with another sheet 
material passage on an upstream side of the image forming means; 
switchback conveying means placed in a part of the resupplying passage for 
reversing the conveyance direction of the sheet material upon reception of 
the sheet material from a conveyer in the image forming apparatus body; 
resupplying means for returning the sheet material to the upstream side of 
the image forming means through the part of the resupplying passage; a 
tray member capable of being open and closed for holding thereon the sheet 
materials conveyed out of an outlet of the sheet material on the image 
forming apparatus body; a passage switching member for switching, in 
association with opening and closing operation of the tray member, the 
conveyance direction of the sheet material (i.e. face-up passage/face-down 
passage); a cover member with a guide portion pivotably movable, in 
association with the opening and closing operation of the tray member, 
located around an inlet for the sheet material of the resupplying passage 
constituting a part of the resupplying passage; detecting means for 
sensing the pivoted position of the cover member to detect the open or 
closed state of the tray member; and automatic selecting means for 
selecting the conveyance direction from either one of passages or the 
resupplying passage by automatically switching the passage switching 
member while the tray member is closed. 
According to the constitution thus formed, resupply of the sheet material 
one side of which recording is made is performed by guiding the sheet 
material from an outlet for the sheet material of the image forming 
apparatus body to the inlet for the sheet material of the resupplying 
apparatus by means of the passage switching means that have switched so 
that the sheet material's conveyance direction is directed to the 
resupplying passage by the operation of the automatic switching means 
while the tray member is closed and by means of the guide portion of the 
cover member disposed around the inlet of the sheet material of the 
resupplying apparatus, so that because the entire sheet material is placed 
within the image forming apparatus body and the resupplying apparatus when 
the sheet material is subject to the resupplying operation (in particular, 
during a waiting period during the switchback conveyance), the apparatus 
does not lose its fine shape and because no opening is made on the 
apparatus, the apparatus can operate with less noise and noise reflected.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
First Embodiment 
Referring to FIG. 1, a reapplying apparatus according to the first 
embodiment of the invention is described. In this embodiment, a laser 
printer is exemplified as an image forming apparatus. 
As shown in FIG. 1, an image forming apparatus body 1 is equipped with a 
conveying means 2 made of plural rollers or the like for conveying a sheet 
material S, a scanner unit 3 emitting information light based on image 
information onto an electrophotographic photosensitive body 4a in an image 
forming section 4, the image forming section 4 forming an image on the 
electrophotographic photosensitive body 4a, a transfer means 5 
transferring the image formed on the electrophotographic photosensitive 
body 4a onto the sheet material S, a fixing means 6 fixing the transferred 
image to the sheet material S, and the like. It is to be noted that the 
image forming section 4 is formed with the electrophotographic 
photosensitive body 4a and at least one of processing means and integrated 
into a unit as a process cartridge detachably attached to the image 
forming apparatus body 1. The processing means can be, for example, a 
charger for charging the electrophotographic photosensitive body, a 
developer for developing latent images formed on the electrophotographic 
photosensitive body, a cleaner for cleaning residual toner on the surface 
of the electrophotographic photosensitive body, or the like. 
The image forming apparatus is constituted to be capable of discharging the 
sheet material S on which recording is made so that the recorded side is 
up (face-up) or down (face-down); the image forming apparatus includes a 
face-down delivery tray 7, serving as a first tray member, for holding 
thereon the sheet material S delivered in facing down, a face-up delivery 
tray 8, serving as a second tray member, capable of being open and closed 
for holding thereon the sheet material S delivered in facing up, and a 
flapper 9 pivotally movable to switch, in association with the opening and 
closing operation of the face-up delivery tray 8, the conveyance direction 
of the sheet material S between a face-up passage and a face-down passage. 
The flapper 9 is constituted to be located at a position shown by a solid 
line in FIG. 1 when the face-up delivery tray 8 is closed for face-down 
operation and at a position shown by a broken line in FIG. 1 when the 
face-up delivery tray 8 is open for face-up operation. A cam member 9b is 
fixed to an end of a shaft 9a of the flapper 9. In the case when the 
recording section records an image on a lower side of the sheet material 
S, the face-down delivery tray 7 and the face-up delivery tray 8 change 
their positions with each other. 
A resupplying apparatus 10 to resupply the sheet material S to the image 
forming section 4 is detachably attached to the image forming apparatus 
body 1 to make recording on one side of the sheet material the other side 
of which recording has been made. The resupplying apparatus 10 is composed 
of resupplying passages A to D as described below, switchback conveying 
means constituted of a roller pair 13 for switchback conveyance and the 
like, a position regulator 22 serving as position regulating means, and 
the like, which are assembled in a frame 30 and integrated as a unit. The 
resupplying apparatus 10 is used upon inserted in an attaching portion 31 
formed in a center of the image forming apparatus body 1. Although the 
image forming apparatus forms images only on one side of the sheet 
material where the resupplying apparatus 10 is not yet attached, the image 
forming apparatus can form images on both sides of the sheet material by 
attaching the resupplying apparatus 10. 
The resupplying apparatus 10 is equipped with an automatic switching device 
11 serving as automatic switching means for automatically switching the 
position of the flapper 9 while the face-up delivery tray 8 is closed to 
select the conveyance direction of the sheet material S between the 
face-down passage and the face-up passage. The automatic switching device 
11 is constituted of a switching lever 11 a pivotable around a shaft 11a1, 
and a plunger, or solenoid, 11b for rendering the switching lever 11a 
pivotably move. A cam follower 11a2 to contact the cam member 9b fixed to 
the flapper 9 is formed at one end of the switching lever 11a, and the 
plunger 11b is coupled to the other end of the switching lever 11a. 
A cover member 12 on which a guide surface 12a introducing into the 
resupplying apparatus 10 the sheet material S conveyed out of the image 
forming apparatus body 1 is formed, is disposed around an inlet for the 
sheet material of the resupplying apparatus 10. The cover member 12 is 
pivotable around a shaft 12b. The switchback conveyance roller pair 13 
rotatable normally and reversely is arranged in a resupplying passage of 
the resupplying apparatus 10 for switchback conveyance, or namely, for 
reversing the conveyance direction, of the sheet material S introduced by 
the inlet for the sheet material S. 
The resupplying apparatus 10 is equipped with an openable body 14 releasing 
part of the resupplying passage and forming a guide. Surface 14a 
constituting part of the resupplying passage. The openable body 14 is 
pivotably supported around a shaft 14b formed at one end of the openable 
body 14. The cover member 12 is pivotably supported around the other end 
of the openable body 14; a boss 12c of the cover member 12 engages a long 
hole 14c in the openable body 14: a resilient member 15 normally urges the 
cover member 12 in a counterclockwise direction. Furthermore, as shown in 
FIG. 1, the numeral 16 is a sensor for detecting as to whether the face-up 
delivery tray 8 is open or closed by detecting the pivoted position of the 
cover member 12; the numeral 17 is a sensor for detecting the position of 
a reversing flapper 18 for guiding a front end of the sheet material S 
reversely transported and detecting as to whether the openable body 14 is 
open or closed. 
In the resupplying apparatus 10, plural resupplying passages A to E are 
formed by means of guide members or the like. The resupplying passage A is 
formed by the cover member 12, the openable body 14, and a curving guide 
member 19a: the resupplying passage B is formed by guide members 20a, 20b 
for storing and guiding the sheet material S conveyed in the reverse 
direction, or under the switchback conveyance: the resupplying passage C 
is formed by the curving guide member 19a and another guide member 19b 
curving similarly to and located inside the guide member 19a. The 
resupplying passage D is formed by a guide member 23 for constituting the 
position regulator 22 as described below. The resupplying passage E is 
formed by guide members 21 a, 21b connecting the position regulator 22, as 
described below, with the image forming section 4. The guide members 21a, 
21b are members on a side of the image forming apparatus body 1. 
The resupplying apparatus 10 further includes the position regulator 22 for 
regulating the crosswise position of the sheet material S conveyed by the 
switchback conveyance roller pair 13. The position regulator 22 includes a 
guide member 23 having plural contacts regulating the position of the side 
edge of the respective sheet material by contacting the side edge of the 
sheet material that may be different in size, and an obliquely conveying 
roller pair 24 conveying the sheet material S in rendering the side edge 
of the sheet material in contact with the contacts of the guide member 23. 
The detailed constitution of the position regulator 22 is described below. 
In the drawings, the numeral 25 is a sensor for detecting as to whether the 
sheet material S exists in the resupplying passage D; the numerals 26, 27 
are drive motors as drive sources for driving the switchback conveyance 
roller pair 13 and the obliquely conveying roller pair 24; the numeral 28 
is a board on which a power source, a controller, or the like are mounted. 
Now, referring to FIGS. 1 to 6, operation of the resupplying apparatus and 
the image forming apparatus equipped with the resupplying apparatus is 
described. With the image forming apparatus, the scanner unit 3 emits 
information light based on image information onto the electrophotographic 
photosensitive body 4a to form a latent image on the photosensitive body 
4a, and the latent image is developed to form a toner image. The sheet 
material S, in synchronous with the formation of the toner image, is 
conveyed from a cassette 2a to the image forming section 4 through a 
pick-up roller 2b, a feeding roller pair 2c, and a register roller pair 
2d, and then, the toner image formed on the electrophotographic 
photosensitive body 4a of the image forming section 4 is transferred onto 
the sheet material S by the transfer means 5. The sheet material S in the 
post-transfer stage is conveyed to the fixing means 6, and the transferred 
toner image is fixed onto the sheet material S. 
The sheet material S thus fixed with the image is then conveyed by a 
conveying roller pair 2e. If the face-up delivery tray 8 is closed at that 
time, since the flapper 9 is located at the solid line position in FIG. 1, 
the sheet material S is introduced by the flapper 9 (the solid line 
position) to a reverse passage 2f, thereby being delivered on the 
face-down delivery tray 7 by a delivery roller pair 2g. That is, this is 
the face-down delivery. 
If the face-up delivery tray 8 is made open in an arrow direction (the 
broken line position) in FIG. 1, the flapper 9 is rotated, in association 
with the opening of the face-up delivery tray 8, in the counterclockwise 
direction to move to the broken line position shown in FIG. 1, thereby 
switching the conveyance direction of the sheet material S. Therefore, the 
sheet material S is introduced by the flapper 9 taking the broken line 
position and delivered onto the face-up delivery tray 8 through a sheet 
material outlet 2h. That is, this is the face-up delivery. 
FIG. 2 shows a condition around the sheet material outlet 2h at a time of 
the face-up delivery. The delivery tray 8, upon opening, contacts an end 
12d formed at a part of the cover member 12 of the resupplying apparatus 
10, thereby rotating the cover member 12 around the shaft 12b in the 
clockwise direction as shown by an arrow in FIG. 2 in opposition to 
resilient force of the resilient member 15. The end 12d of the cover 
member 12 shifts below the sheet material outlet 2h of the image forming 
apparatus body 1 to shut the resupplying passage A, so that the sheet 
material S delivered in facing up is delivered onto the face-up delivery 
tray 8 and is accumulated thereon. Since a projection 12e formed on the 
cover member 12 goes to the sensor 16 at that time, the image forming 
apparatus can detect the face-up delivery state in which the face-up 
delivery tray 8 is open. In other words, the resupply (both side mode) is 
possible only where the face-up delivery tray 8 is closed (the face-down 
delivery state). 
In FIG. 3, when the plunger (solenoid) 11b is attracted in an arrow 
direction while the face-up delivery tray 8 is closed, the switching lever 
11a rotates around the shaft 11a1 in the clockwise direction, or an arrow 
direction in FIG. 3. Then, the cam follower 11a2 formed at one end of the 
switching lever 11a pushes the cam member 9b fixed to the flapper 9, 
thereby rotating the flapper 9 around the shaft 9a in the counterclockwise 
direction, or an arrow direction, and therefore, the image forming 
apparatus enters the face-up delivery state as described above. That is, 
the operation of the plunger 11b without opening the face-up delivery tray 
8 switches the conveyance direction of the sheet material S. 
As described above, the conveyance direction of the sheet material S can be 
switched by co-operation of the flapper 9 and the automatic switching 
device 11. That is, this conveyance direction is determined by a 
combination of opening and closing condition of the face-up delivery tray 
8 in association with the operation of the flapper 9 and resting and 
operating condition of the automatic switching device 11 for switching the 
flapper 9. Specifically, the image forming apparatus can select one of 
three modes: a first mode to introduce the sheet material S onto the 
face-up delivery tray 8 by opening the face-up delivery tray 8; a second 
mode to introduce the sheet material S onto the face-down delivery tray 7 
by placing the flapper 9 at a first position shown by the solid line in 
FIG. 1 while the face-up delivery tray 8 is closed, and a third mode to 
introduce the sheet material S into the resupplying apparatus 10 by 
placing the flapper 9 at a second position shown by the broken line in 
FIG. 1 while the face-up delivery tray 8 is closed. 
After subject to fixing, the sheet material S conveyed by the conveying 
roller pair 2e changes its conveyance direction by operation of the 
flapper 9, so that the sheet material S is conveyed in the resupplying 
passage A in the resupplying apparatus 10 through the sheet material 
outlet 2h of the image forming apparatus body 1. As shown in FIG. 4, then, 
this sheet material S passes through the reverse flapper 18 in being 
guided along the guide surface 14a of the openable body 14, is clamped and 
conveyed by the switchback conveyance roller pair 13, and is conveyed in 
the resupplying passage B. 
The reverse flapper 18 is supported pivotably around a shaft 18a and 
includes a contact 18b in contact with the sheet material S to be 
conveyed, a guide portion 18c guiding the front end of the sheet material 
S transported, as the switchback conveyance, or in the reverse direction, 
a flag portion 18d formed at an end of the shaft 18a. If no sheet material 
S exists in the resupplying passage A, the reverse flapper 18 maintains 
its position as shown in FIG. 3 as the part of the reverse flapper 18 
contacts a contact 14d formed on the openable body 14. If the sheet 
material S passes through the reverse flapper 18 as shown in FIG. 4, the 
reverse flapper 18 rotates in the counterclockwise direction around the 
shaft 18a, and then, existence of the sheet material S in the resupplying 
passage A is detected upon departure of the flag portion 18d of the 
flapper 18 from the sensor 17. 
As shown in FIG. 5, when the sheet material S is further conveyed and when 
the rear end of the sheet material S passes through the reverse flapper 
18, the reverse flapper 18 rotates around the shaft 18a in the clockwise 
direction, thereby rendering the flag portion 18d thereof enter in the 
sensor 17 again. That is, the drive motor 26 reversely drives upon 
detection of the rear end of the sheet material S, and in other words, the 
switchback operation is performed. According to this switchback operation, 
the switchback conveyance roller pair 13 is also reversely driven, and as 
a result, the sheet material S is conveyed into the resupplying passage C 
in being guided by the guide portion 18c of the reverse flapper 18, as 
shown in FIG. 6. 
The resupplying passage C is curved along the conveyance direction of the 
sheet material S. The sheet material S reversely conveyed by the 
switchback conveyance roller pair 13 is conveyed along the guide member 
19a, 19b. When the front end of the sheet material S is entered in the 
resupplying passage D, the sheet material S is introduced into the 
position regulator 22. 
Referring to FIGS. 7, 8, the position regulator 22 is described. The 
position regulator 22 includes a guide member 23 having a plurality of 
contacts for regulating the positions of side edges of the sheet materials 
different in size, two pairs of obliquely conveying roller pairs 24 sewing 
as resupplying means. The two pairs of the obliquely conveying roller 
pairs 24 have substantially the same constitution to each other and 
include a conveying roller 24c for driving, and a roller 24g driven in 
obliquely pushed by the conveying roller 24c, respectively. Specifically, 
the conveying rollers 24c made of frictional material is fixed to one end 
of an drive shaft 24b rotatably supported to the guide member 23 by a 
bearing 24a, and a belt pulley 24d is fixed to the other end of the drive 
shaft 24b. Between two pulleys 24d, 24d is a belt 24e tensioned for 
transmitting drive force. A gear 24f to which the drive force is 
transmitted from the drive motor 27 is fixed to an end of one drive shaft 
24b. Both of the conveying rollers 24d, 24d are driven by this mechanism. 
Each roller 24g is provided at a position corresponding to the position of 
the respective conveying rollers 24c so as to be obliquely inclined from 
the rotary center of the drive shaft 24b, is pushed to the conveying 
roller 24c by a resilient member 24h, and is supported so as to be driven. 
Two guide surface 23a, 23b are formed at the sheet entry area of the guide 
member 23 so that a sheet material SA with a wide width is conveyed to a 
passage DA and that a sheet material SB with a narrow width is conveyed to 
a passage DB. Contact guides 23c to 23f are formed to regulate the 
crosswise position of the side edges of the respective sheet materials, 
corresponding to the sheet materials SA, SB having their crosswise sizes 
(for example, A4 and B5 sizes) different from each other, and are formed 
in a stepwise shape to extend in a direction perpendicular to the 
conveyance direction of the sheet materials S. On a side at which the side 
edge of the sheet material S contacts the guides by operation of the 
obliquely conveying rollers 24, particularly, the contact guides 23c, 23d 
are disposed to serve as a positional reference in the crosswise direction 
of the sheet materials S. In this embodiment, the contact guide 23c 
arranged on an upper side provides a reference for sheet materials SA 
having a larger A4 size in the crosswise direction; the contact guide 23d 
arranged on a lower side provides a reference for sheet materials SB 
having a smaller B5 size in the crosswise direction. A guide 23g is formed 
between the resupplying passages DA, DB on the reference side to keep the 
sheet material SB having the smaller crosswise size located in the 
resupplying passage DB away from the resupplying passage DA. Similarly, a 
guide 23h is also formed between the resupplying passages DA, DB on the 
non-reference side. Inclined surfaces 23i to 23l are formed at an entry 
area for the sheet materials of the guide member 23 to broaden the entry 
opening so that the sheet materials conveyed by the switchback conveyance 
roller pair 13 are easily entered into the position regulator 22. 
The respective sheet materials SA, SB introduced by the position regulator 
22 thus constituted, are conveyed as shown in FIG. 9, notwithstanding 
their crosswise sizes, while one side edge of the sheet materials SA, SB 
is in contact with the respective guide portions 23c, 23d according to the 
operation of the two sets of the obliquely conveying rollers 24, and 
therefore, the crosswise position of each sheet material is regulated 
adequately. After regulated, the sheet material S conveyed by the 
obliquely conveying roller pairs 24 is resupplied to the image forming 
section 4 through a passage E from the rear end of the sheet material S 
with an up-side-down state from the original face state. Then, the sheet 
material S is subject to image forming operation as described above, and 
with images on both sides, is delivered onto the face-down delivery tray 7 
by the delivery roller pair 2g and held thereon. 
If paper jamming occurs in the resupplying apparatus 10, the resupplying 
passages A to C can be broken up by opening the openable body 14 as shown 
in FIG. 10, so that the jammed sheet material can be removed easily. Since 
the openable body 14 is coupled pivotably to the cover member 12, if the 
openable body 14 is made open as shown in FIG. 10, the cover member 12 is 
also made open together. The projection 12e of the cover member 12 is 
escaped from the sensor 16 at that time, and the flag portion 18d is also 
escaped from the sensor 17 in conjunction with a clockwise rotation of the 
reverse flapper 18 around the shaft 18a caused by outgoing movement of the 
contact 14d of the openable body 14. That is, the combination of the two 
sensors 16, 17 gives information as to whether the openable body 14 is 
open or not, and if the openable body 14 is open, neither of the image 
forming apparatus 1 and the resupplying apparatus 10 operate. 
When the image information light (laser light) is scanned onto the image 
forming section 4 from the scanner unit 3, the image forming section 4 can 
operate corresponding to various sizes of the sheet materials by changing 
the home position of the laser beam in accordance with kinds of the 
resupplied sheet materials. For example, even if an LTR paper is conveyed, 
instead of the sheet material in the A4 size, into the resupplying passage 
DA, or even if an EXEC paper is conveyed, instead of the sheet material in 
the B5 size, into the resupplying passage DB, the image forming section 4 
can always produce images in maintaining a constant margin on the 
reference side notwithstanding the kinds of sheet materials by shifting 
more or less the home position of the laser beam. 
Other Embodiments 
Although in the embodiment above the two resupplying passages are formed on 
both sides of the guide member 23 of the position regulator 22, this 
invention is not limited to this feature and can be formed with the guide 
member 23 in a shape, for example, shown in FIG. 11. The guide member 23 
is formed with, on the reference side, the resupplying passages DA, DB 
made of guide surfaces 23a, 23b, contact guides 23c, 23d, and a guide 23g 
and with, on the non-reference side, no resupplying passage. The guide 
member 23 can obtain the same effects as the above guide member 23. 
As shown in FIG. 12, the image forming apparatus can correspond a special 
sheet material having an extremely narrow width such as of post cards, 
business cards, and envelopes, by providing, to the position regulator 22, 
a resupplying passage DC made of an additional guide surface 23m, a 
contact guide 23n, and a guide 23p, and obliquely conveying roller pairs 
24. By providing plural resupplying passages can the image forming 
apparatus correspond to sheet materials of various sizes. 
The image forming apparatus can as shown in FIG. 13 regulate the crosswise 
position of the sheet material S supplied from the cassette 2a by 
disposing the position regulator 22 thus constituted on the upstream side 
of the image forming section 4. At that time, a wide sheet material SA is 
conveyed to a lower resupplying passage DA whereas a narrow sheet material 
SB is conveyed to an upper resupplying passage DB, and both sheet 
materials are then conveyed to the image forming section 4 with the 
regulated position. According to the position regulator 22 thus 
constructed, the image can be precisely placed on the respective sheet 
materials S because the crosswise position of the sheet material S is 
regulated immediately before the sheet material S is conveyed into the 
image forming section 4. 
As shown in FIG. 14, a supplying apparatus 29 such as a multiple feeder or 
a manual feeder may be arranged, in addition to the structure above, 
immediately on an upstream side of the position regulator 22, thereby 
enabling the image forming apparatus to regulate the crosswise position of 
the sheet material S easily and precisely only by providing an additional 
coarse guide on the side of the supplying apparatus 29. 
As shown in FIG. 15, the position regulator 22 thus constituted can be 
arranged immediately on an upstream side of the delivery roller pair 2g 
disposed near the outlet for the sheet materials S. In such a situation, 
similarly, a wide sheet material SA is conveyed to a resupplying passage 
DA whereas a narrow sheet material SB is conveyed to a resupplying passage 
DB, and both sheet materials are then conveyed while their positions are 
regulated and delivered on the face-down delivery tray 7 by means of the 
delivery roller pair 2g. Accordingly, sheet materials S (bundle of sheet 
materials) can be held on the face-down delivery tray 7 with the precise 
positions of the sheet materials S. 
It is to be noted that in the embodiments shown in FIGS. 13 to 15, the 
position regulator 22 in the resupplying apparatus can be omitted. 
Although in the embodiments above the laser printer is exemplified as the 
image forming apparatus, this invention is not limited to this feature, 
and other image forming apparatus such as a photocopier, a facsimile 
machine, and a word processor, can obtain substantially the same effects. 
Although in the embodiments above, the face-down delivery tray 7 and the 
face-up delivery tray 8 serve as the first tray member and the second tray 
member, respectively, the delivery feature as to which face of the sheet 
material S is up is not limited to this. For example, when the image 
forming section 4, which is formed on the upper side of the passage in the 
embodiments, is formed on the lower side of the passage, the delivery 
feature is not limited to one of the above embodiments, and the face-down 
delivery tray and the face-up delivery tray may serve as the second tray 
member and the first tray member, respectively. 
As described above, according to the embodiments of this invention, the 
sheet materials one side of which recording is made are resupplied by 
transportation of the sheet materials from the sheet outlet of the image 
forming apparatus body to the sheet inlet of the resupplying apparatus by 
means of the passage switching member that switched by the automatic 
switching means so that the resupplying passage serves as the sheet 
material conveyance direction while the tray member is closed and of the 
guide member of the cover member arranged around the sheet inlet of the 
resupplying apparatus, so that the image forming apparatus does not lose 
its fine appearance because the entire sheet material is contained within 
the image forming apparatus and the resupplying apparatus while the sheet 
material is subject to resupplying operation, in particular, during a 
waiting period for switchback conveyance, and so that since no opening is 
made, general and reflected noises are reduced. 
Since the image forming apparatus is formed with the openable body having 
the guide portion for releasing part of the resupplying passage and 
forming part of the resupplying passage, paper jamming is easily treated 
only by opening the openable body, thereby improving user's 
controllability. Furthermore, since the image forming apparatus is formed 
with the sheet material sensors for detecting as to whether the openable 
body is open or closed and as to whether the sheet material exists in the 
resupplying apparatus to be broken up, the apparatus does not start 
operating while the openable body remains open. The switchback conveyance 
is conducted smoothly because the sheet material sensors are arranged in 
proximity of the upstream side of the switchback conveying means formed in 
the resupplying passages and have the guide portions to guide the front 
end of the sheet material conveyed in the reverse direction, and the image 
forming apparatus can be formed with less costs because of the reduced 
number of parts. 
Since the position regulating means for regulating the position in the 
crosswise direction of the sheet material conveyed by the switchback 
conveying means includes the guide member having a plurality of contacts 
for regulating positions of the respective sheet materials of different 
sizes thereof by contacting the side edges of the sheet materials, and 
obliquely conveying means for conveying the sheet materials while 
rendering the side edges of the sheet materials in contact with the 
contacts of the guide member, and since the contacts of the guide member 
are formed at positions corresponding to the respective sizes of the sheet 
materials so as to extend in a stepwise shape from the outer side toward 
the center of the sheet material in a perpendicular direction to the 
conveyance direction of the sheet material, the constitution of the 
position regulating means is simplified, thereby enabling the apparatus to 
reduce costs, energy consumption, size, weight, and noise. 
The resupplying apparatus can make the size thereof compact, because the 
resupplying apparatus has the curving guide member located between the 
switchback conveying means and the position regulating means and curved 
along the conveyance direction of the sheet material for guiding the sheet 
material conveyed in the switchback conveyance, and because the 
resupplying apparatus has a driver source located inside of the curved 
guide member for driving the resupplying apparatus. 
The image forming apparatus can precisely position the images on the sheet 
materials S by disposing the position regulating means thus constituted on 
a side of the image forming apparatus, or more specifically, by disposing 
it on the upstream side of the image forming section in the sheet material 
conveyance direction, because the crosswise position of the sheet material 
is regulated immediately before the sheet material S is conveyed into the 
image forming section. Furthermore, by providing the position regulating 
means immediately on the upstream side of the sheet outlet in the sheet 
material conveyance direction, the position of the sheet materials (bundle 
of sheet materials) held on the delivery tray can be regulated. 
This invention, since thus constituted, can be suitable regarding its 
appearance and can reduce noise. As described above, though the preferred 
embodiments of the invention is described, a person skilled in the art can 
easily conceive other variations. Accordingly, this invention is not 
limited to the embodiments above, and variations of the invention are to 
be covered by claims as set forth below.