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Патент USA US3095204

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June 25, 1963
‘G. P. TAlLLlE
~Filed March 1, 1962
5 Sheets-Sheet 1
FIG. 1
June 25, 1963
Filed March 1, 1962
3 Sheets-Sheet 2
June 25, 1963
Filed March 1, 1962
3 Sheets-Sheet 3
Patented June
25, ’1963
quired for making a Xerographic reproduction on the
support material before it is fed from the machine. It
is, therefore, an object of this invention to improve paper
guide means for use in endless belt type sheet conveyors
gorgoration, Rochester, NE!” a corporation of New 5 to permit the overall length of a sheet conveyor to be
or '
reduced while still permitting uniform travel of a sheet
Gordon P. Taiilie, Rochester, N321, assignor to Xerox
Filed Mar. 1, 1962, Ser. No. 176,530
3 Claims. (Cl. 271-7?)
material conveyed thereby.
Another object of this invention is to improve paper
guide rolls to guide sheet material around a turn in a
This invention relates to paper guide rolls for use in
the sheet conveyor mechanism of a Xerographic repro- 1O conveyor mechanism at a uniform rate of speed.
It is a further object of this invention to improve paper
ducing apparatus.
guide rolls so that a malfunction of the paper guide roll
More speci?cally, the invention relates to an improved
will not interfere with the operation of the sheet con
paper guide roll for use in a conveyor mechanism to per
veyor mechanism.
mit a sheet forwarded by the conveyor mechanism to
It is a further object of this invention to improve
travel, in a curved path, at a uniform lineal speed.
15 paper guide rolls so that they are economical to produce,
In the process of Xerography, an electrostatic latent
reliable in operation, and will fail safe if malfunction
image of copy to be reproduced is formed on a xero
graphic plate, usually in the form of a rotating drum,
These and other objects of the invention are attained
and is developed with an electroscopic powder or toner
material to form a powder image of the copy on thie 20 by means of a guide plate that is freely rotatable to per
mit passage of a sheet vgripper mechanism and biasing
drum. The powder image is then transferred to a sheet
means on the guide plate to return the plate to a position
of support or transfer material, usually paper.
Thus, in the ?eld of Xerography, an image is developed
on a Xerographic plate, the image being secured to the
xerographic plate by an electrostatic force only, and with
in the influence of this electrostatic force the image can
very easily be smeared or smudged. In the transfer
process, a sheet of support material is brought into con
tact with the image on the Xerographic plate and the
image is then transferred and held electrostatically on the
supporting the sheet of material received by the gripper
mechanism. Failure of the biasing means will leave the
guide plate in a position that will not interfere with the
path of travel of the next succeeding gripper mechanism.
Thus, this arrangement provides a device that, even under
failure of one of the parts, will not interfere with the
operation of the machine.
The invention is disclosed in the appended drawings, in
support material. Unlike many types of mechanical
FIG. 1 is a schematic illustration of a type of Xero
forces, the electrostatic ‘forces binding the image body
graphic reproducing machine in which the present in
either to the Xerographic plate or later to the support
vention may advantageously be employed;
material are comparatively weak in preventing lateral
FIG. 2 is a perspective view of a sheet conveyor system
motion of the image body away from the xerographic 35
embodying the present invention;
plate surface or from the surface of the material.
FIG. 3 is a sectional view of the paper guide roll taken
When transfer is to be effected from a ‘moving xero
line 3—3 of FIG. 2;
graphic plate onto a support material in an automatic
FIG. 4 is a sectional view of the paper guide roll of
xerographic reproducing machine, the support surface
must be moved into contact with the xerographic plate 40 PEG. 3, shown in a de?ected position; and,
FIGS. 5 and 6 are sectional views similar to FIGS. 3
for synchronous movement therewith during the transfer
and 4, showing an alternate embodiment of the invention.
process to permit proper registered image transfer from
Referring now to FIG. 1, there is shown a continuous
the plate to the support material. If relative movement
Xerographic reproduction machine of the type disclosed in
between the plate and support material is permitted along
the areas of transfer contact, smearing or smudging of 45 the above-mentioned copending application in which a
paper guide roll may advantageously be employed. The
the images will occur.
Xerographic apparatus comprises a Xerographic plate 10,
One type of conveyor mechanism employed in Xero
including a photoconductive layer of light receiving sur
graphic reproducing ‘apparatus for conveying sheet sup
face on a conductive backing and formed in the shape of
port material from a receiving station into transfer con
tact with a xerographic plate and then to a delivery sta- 50 a drum, which is positioned on a shaft *11 journaled in a
tion is disclosed in copending application Serial No.
46,463, ?led August 1, 1960, in the name of Robert A.
Hunt and Gordon P. Taillie. Such an arrangement in
frame (not shown) to rotate in the direction indicated
by the arrow to cause the drum surface sequentially to
pass a plurality of Xerographic processing stations.
For the purpose of the present disclosure, several xero
or equivalents, for supporting the chains, and at least one 55 graphic processing stations in the path of movement on
the surface may be described functionally, as ‘follows:
sheet gripper connected to the chains at right angles to
A charging station A, at which a uniform electrostatic
their path of movement, for movement through a closed
charge is deposited on the photoconductive layer of the
circuit from a receiving station to a delivery station.
cludes a pair of endless chains, or equivalents, sprockets,
Xerographic drum;
Heretofore, this type of conveyor mechanism has proved
An exposure station B, at which a light or radiation
satisfactory for use in Xerographic apparatus, provided 60
pattern of copy to be reproduced is projected onto the
the conveyor mechanism is of such a length as to permit
drum surface to dissipate the drum charge on the exposed
a substantially long straight run of sheet material to and
from the xerographic plate to ensure a uniform rate of
travel of the sheet material.
It is apparent then that the side of the conveyor mecha
nism of this type governs the size of the Xerographic ap
paratus; that is, the bigger the sheet of support material
conveyed by the conveyor, the longer the length of the
conveyor, and therefore, the greater the outside physical
dimension of the entire Xerographic apparatus. Further
more, the greater the length of travel required for a sheet
of transfer material, the greater the period of time re
areas thereof, and thereby form a latent electrostatic im
age on the copy to be reproduced;
A developing station C, at which a xerographic develop
ing material including toner particles having an electro—
static charge opposite to that of the electrostatic latent
image are cascaded over the drum surface, whereby the
toner particles adhere to the electrostatic image to form
a xerograp-hic powder image in the con?guration of the
copy to be reproduced;
A transfer station D, at which the xerographic powder
image is electrostatically transferred from the drum sur
face to a transfer material or support surface; and,
A drum cleaning and discharge station E, at which the
drum surface is brushed to remove residual toner particles
remaining on the drum after image transfer, and at which
the drum surface is exposed to a relatively bright light
source to effect substantially complete discharge of any
means of a corona transfer device 29 located at or immedi
ately after‘ the point of cont-act of the support material
and the xerographic drum. The corona transfer device
is substantially similar ‘to the corona ‘discharge device 12
that is employed at charging station A, in that it includes
an array of one ‘or more corona discharge electrodes that
are energized from a suitable high potential source and
residual electrostatic charge thereon.
extend transversely across the drum surface and are sub
At charging station A, a corona discharge array 12 of
stantially enclosed within a shielding member. In oper
one ‘or more discharge electrodes, that extend transversely 10 ation, the electrostatic ?eld created by the corona dis
‘across the drum surface and are energized from a high
charge ‘device is effective to cause the transfer material to
potential source, are substantially enclosed within a shield
electrostatically adhere to the drum surface, whereby the
ing member. The charging apparatus may be of the type
transfer material moves synchronously with the drum sur
disclosed in Walkup Patent 2,777,957.
face in contact therewith. The electrostatic ?eld is also
Next subsequent thereto in the path of motion of the 15 effective to attract the toner particles comprising the pow
xerographic drum is exposure station B, which contains
der image from the drum surface and cause them to
an optical scanning or projection mechanism generally
adhere electrostatically to the surface of the transfer ma
designated 13 and a light shield member 14. The optical
scanning mechanism consists of a lamp LMP1 which pro
As the paper gripper is advanced by the chain conveyor
vides a uniform lighting source of projecting a light image
it strips the sheet of transfer material from the drum and
of a ?lm 13, or other copy to be reproduced. Projector
14 contains a series of optical lenses which project the
image onto an object mirror 16 in light shield 14. Object
mirror 16 re?ects the image through aperture 17 onto the
surface of the rotating xerographic drum. ‘In the commer
cial form of this machine, a ?lm holder (not shown) is
inserted between lamp LMPl and projector 15, and is sup
ported by a movable carriage on the projector. The ?lm
holder is arranged for movement in a path to traverse the
optical path of the lens whereby the subject image of the
?lm is scanned in timed relation to the movement of the
light receiving surface of the xerogr'aphic drum and a [light
corresponding to the subject image is transferred to the
surface of the xerographic drum.
Adjacent to the exposure station is a ‘developing station
in which there is positioned a housing ‘18 for containing a
suitable “two component” developing apparatus. In this
arrangement, a bucket-type conveyor 20 having a suitable
driving means (not shown) is used to carry developing
material 21 [to the upper part of the housing where it is
cascaded down over a chute 22 onto the xerographic
As the developing material is cascaded over the xero
graphic drum, toner particles are pulled away from the
carrier component of the ‘developing material ‘and de
posited ion the drum to form powder images. The carrier
components pass off the drum into the lower portion of
housing 18, for recycling. As powder images are formed,
additional toner material may be supplied to the develop
ing material in proportion to the amount of toner de
posited on the drum surface. For this purpose, there is
provided a container 23 for toner '24 to be added to the
developing material 'at a rate determined by a control gate
transports it to a ?xing device, such as a heat fuser 30,
where the xerognaphic powder images previously trans
ferred to the support surface are permanently ?xed there
to. Suitable support rods 31 are provided to guide the
trailing edge of the sheet of support material in proper
relation to the heat fuser. The heat fuser 34} contains
electrical heating elements R1, R2, and R3, which are
connected to a suitable source of power ‘(not shown).
After fusing, the ?nished copy is discharged ‘from the
apparatus at a sheet delivery station 71. To accomplish
this, there is provided a pair of delivery rollers 32 and 33
which receive the sheet from a paper gripper and deliver
it to a collecting tray 34;
After the image is transferred from the xerographic
drum to the support surface, the xerographic drum rotates
past the cleaning station E ‘to remove any residual charge
and developing material that may remain on the xero
graphic drum. The corona precleaning device 35, similar
to corona charging device 12, is positioned to impose an
electrostatic charge of suitable polarity on the drum and
powder adherent thereto, to aid in effecting removal of
the powder from the drum surface. A rotatable brush
35 is positioned to eifect removal of this residual powder
from the drum and a source of light [such as LMPZ ?oods
the drum surface with light to cause dissipation of any
residual electric charge remaining on the drum. For col
lecting the powder particles removed by the brush there
is provided a dust hood 37.
For removing dust particles from the brush and dust
hood, an exhaust duct 38 is arranged to cover a slot that
extends transversely across ‘the vhood 37 and is connected
to a ?lter bag 39 in a ?lter box 49. Motor driven fan
units 41 connected to the ?lter box, produce a ?ow of
air through the ?lter box drawing air through the area
After passing developing station C, the xerographic 55 surrounding the xerogriaphic drum and the dust hood,
drum rotates past image transfer‘ station D. At the trans
fer station, a sheet feeding mechanism is adapted to feed
sheets of transfer material, usually paper, successively to
the xerographic drumin registration with the formed
xerographic powder image on the said drum.
In the embodiment shown, the sheet feeding mecha
nism includes 1a chain conveyor 26 carrying one or more
the air entrains powder particles removed from the drum
by the ‘brush as the air ?ows through the dust hood.
Powder particles are separated from the air as it ?ows
through the ?lter bag so that only clean air reaches the
motor fan unit.
Any residual electric charge remaining on the Xero
graphic drum is ‘dissipated by light from ?uorescent‘lamp
paper grippers 27 in a circuit between sheet feeding sta
LMPZ, mounted in lamp housing 42. A suitable power
tion ‘79 and a sheet ‘delivery station 71. Means are pro
source is provided for energizing the ?uorescent lamp.
vided to activate the grippers to cause the grippers to 65
Operation of [the paper conveyor is effected by actua
take hold of the front edge of a sheet of support material
of a limit switch LS1, upon the insertion of a sheet
28’ inserted into the machine at the station '74} and to hold
of transfer material into a paper gripper, and the opera
the sheet while traveling to the delivery station and there
tion of the paper conveyor is terminated, after a sheet of
to release the sheet for removal from the machine. In
transfer material “has been conveyed from the front of
the embodiment shown, a sheet of transfer material is fed 70
the machine to the delivery rollers, by limit ‘switch LS2
manually by ‘an operator to paper gripper 27 and is for
which is actuated‘ by one of ‘a pair‘o‘f actuators 42 on the
warded by the paper gripper into contact with a xero
paper conveyor. As the paper conveyor is operated, the
graphic drum at image transfer station D.
‘actuator 42 contacts limit switches ‘LS3 and LS4 which
The transfer of a xerographic powder ‘image from
are used to effect the operation of the projection ap
the drum surface to the support material is eifected by 75 paratus.
Referring now to FIG. 2, the conveyor chains 26 are
mounted on pairs of sprockets 43, 44, 45, 46 and 47,
which are rotatably mounted on shafts between side frame
members 48 and 49. Each ‘gripper bar 27 is mounted
on chains 26 and is carried in a continuous path around
each of the sprockets back to the original position as
shown in FIG. 2. Mounted between the pair of sprockets
46 on shaft 50 which is fastened at its ends in the plates
48 and 49, is a paper guide roll 51 which constitutes the
essence of this inventtion. As ‘shown in FIGS. 2 and 3,
paper guide roll 51 consists of a guide plate 55 mounted
mally biased position by means of tension spring 62 and
provides a surface over which the support material may
pass without shortening the distance between the gripper
bar and the point of contact with the xerographic ‘drum.
Spacers 59 contain limiting pins 72 and 63. Limiting
pin 72 regulates the normally biased position of guide
plate 58 and limiting pin 63 regulates the position of guide
plate 58 in the de?ected position. Limiting pin 63 is a
fail-safe device such that, should tension spring 62 fail,
the normal weight of guide plate 63 would cause the plate
on a pair of spacers 52 which are rigidly secured to
to come to rest on pin 63. Thus, the guide plate would
remain in a position permitting the passage of paper
shaft 56 by means of set screws 54. Paper guide roll 51
is pivotally mounted on spacers 52 by means of pin 53.
Guide plate 55 is formed with a vcircular portion cover
ing an arc of approximately 90° and a ?at portion extend
swing in such a position that the gripper bar would come
in contact with the underside of the flat portion of the
ing from :the circular portion in the direction of the front
of the machine. On the end of the flat portion is a coun
terweight 56 attached by means of rivets 57. Guide
gripper 27. Without pin 63, should the tension spring
62 fail, the guide plate under its normal weight would
plate 53 and would jam, causing damage to the machine
and possibly stalling the movement of the gripper bar.
Continuous movement of the gripper bar is necessary
plate 55 is freely rotatable on pin 53 and is normally 20 since at this point, a portion of the transfer material is
passing under the heat fuser 30. Any restriction in its
pivoted, by the counterweight 56, which is secured to
normal movement would delay the movement of the
the underside of the flat portion of guide plate 55, so that
transfer material and cause excessive heating and possi
the ?at portion extends downward toward the front of
ble ?re.
the machine. That is, guide plate 55 is in such a posi
In the normal operation of the machine, a micro?lm
tion that the ?at portion is at an angle to the path of 25
card is placed in projection 15, an image of which is pro
travel of the gripper bar 27, and the circular portion of
jected by means of LMPl through projector 15, mirror
guide plate 55 is in interference relationship with the
16 onto xerographic drum 10. A sheet of transfer ma
gripper bar 27 as it travels in its normal path around
terial or support surface, is inserted into the machine at
sprockets 46.
The freedom of movement of the guide plate 55 on pin 30 feeding station 70 and activates limiting switch LS1, so
that gripper bar 27 will grip the sheet of transfer material
53 permits the gripper bar 27 to de?ect the guide plate
and carry it into contact with the xerographic drum at
from its normally biased position and allows gripper bar
image transfer station D. The electrostatic image on the
27 to pass around sprockets 46, at which point counter
drum is developed at developing station C, and transferred
weight 56 causes the guide plate 55 to return to its biased
position as shown in FIG. 3. The guide plate forms an 35 to the sheet of transfer material at station D. Gripper
bar 27 then carries the sheet of transfer material in spaced
elongated single guide for a sheet of transfer material,
relation to the heat fuser 30. After passing under the
the radius of the peripheral surface of the guide being
heat fuser 30, the gripper bar comes into interference con
equal to the pitch radius of the sprockets 46 for the pur
pose as to be described hereinafter.
tact with guide plate 58 and ‘causes the guide plate to ro
While the sheet of transfer material is being pulled at 40 tate about pin 53. The sheet of transfer material passes
between rollers 32 and 33 at which point the gripper bar
one end ‘by the paper gripper and held back at its other
releases the sheet of transfer material. Guide plate 55
end by the tacking force onto the xerographic drum, the
returns to its normally biased position where it serves as
paper guide roll will remain rotated substantially in the
a guide surface for the sheet of transfer material. Roller
position shown in FIG. 4, until the paper gripper 27
passes over sprockets 46, at which point the paper guide 45 33 and idler roller 32 move the transfer material and de
posit it in tray 34.
roll returns to its normally biased position, as shown in
Although the invention, in each of its forms is described
FIG. 3, and provides a guide path for the sheet of trans
as used with a conveyor system of an automatic xero
fer material. If the guide roll were not present, the
graphic reproduction machine, it will be apparent to those
distance between the forward edge of the sheet of ma
terial and the contact with the xerographic drum would 50 skilled in this or related arts that it may readily be applied
to any system in which it is required to handle sheets of
be shortened as the gripper bar passes around sprockets
material by means of a conveyor system. Therefore,
46. However, the guide roll provides a surface for the
since many changes could be made in the above construc
material to pass over and still maintain .the same tension
tion and many apparently widely different embodiments
on the support surface by the gripper bar as if the gripper
bar were traveling in a straight path away from the xero 55 of this invention could be made without ‘departing from
the scope thereof, it is intended that all matter contained
graphic drum.
in the speci?cation and drawings be interpreted as illus
FIGS. 5 and 6 show another embodiment of the inven
trative and not in a limiting sense.
tion. The paper guide roll 58 is formed in the same
What is claimed is:
manner as that described in the preferred embodiment,
1. In a sheet conveyor mechanism including a pair of
that is, it includes a segment of a circle and a ?at portion 60
extending toward the front of the machine. Spacer plates
endless chains mounted on parallel pairs of sprockets and
59, secured to shaft 50 by means of set screws 60, con
a sheet gripper mechanism mounted on said endless
tain a pin 61 to which guide plate 58 is rotatably at
a sheet guide roll means consisting of
tached. A tension spring 62 is secured to spacer 59 and
an arcuate guide plate having a ?at segment in interfer
to the end of the flat portion of guide plate 58. Spring 65
62 causes the guide plate 58 to be held in a normally
ence relation with the path of travel of the gripper
biased position such that the ?at portion is at an ‘angle
to the path of travel of gripper bar 27.
said guide plate being pivotably mounted on one or
In operation, in the same manner as previously de
scribed, the gripper bar 27 comes in contact with guide 70
plate 58 and de?ects the ‘guide plate into the position
shown in FIG. 6. Guide plate 58 is de?ected around pin
61 permitting f-ree passage of gripper bar 27 and extend
ing tension spring 62. After the gripper bar passes around
sprocket 46, guide plate 58 is free to return to its nor 76
more collars rigidly secured to a shaft between a pair
of said parallel sprockets,
and a counterweight positioned on the underneath side
of said ?at segment to position the arcuate section
coincidental with the pitch circle of said sprockets.
2. In a sheet conveyor system including a sheet gripper
mechanism mounted on a pair of endless chains that
move in a path around a series of parallel sprockets,
a sheet guide roll consisting of
a plurality of collars rigidly mounted on a shaft be
tween a pair of said sprockets,
a pin mounted on each of said collars,
an arcuate guide plate pivotably mounted on said pins,
said guide plate having a curved peripheral section
equal to the pitch circle of said sprockets and a ?at
segment attached to said curved section,
and spring means connected to said ?at section and to
said collars to normally bias said guide plate in a
position wherein said curved section is coincidental
with the pitch circle of said sprockets and said ?at
section is ‘in interference relation with the path of 15
travel with‘ said gripper mechanism.
3. The apparatus of claim 2, wherein said collars con
tain two positioning pins, said pins extending outwardly
in interference relationship with the pivotable movement
of said guide plate, and said pins positioned on said col
lar to limit the maximum movement of said guide plate,
whereby, upon failure of said spring means, the move
ment of said guide plate will be limited by, said position
ing pins and will not interfere with the movement of
said gripper mechanism.
References Cited in the ?le of this patent
Harrold ____________ __ Apr. 23, 1940
Kaddleland ___________ _.. Jan. 8, 1946
Luehrs et a1. __________ __ Ian. 1, 1957
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