U.S. patent number 3,926,519 [Application Number 05/475,689] was granted by the patent office on 1975-12-16 for control device for an electrophotographic printing machine.
This patent grant is currently assigned to Xerox Corporation. Invention is credited to Robert P. Rebres.
United States Patent |
3,926,519 |
Rebres |
December 16, 1975 |
Control device for an electrophotographic printing machine
Abstract
A cassette which holds a stack of sheet material in an
electrophotographic printing machine. The printing machine includes
a fuser having at least two temperature set-points. When positioned
in the sheet feeding apparatus, the cassette is arranged to switch
the fuser temperature set-point from a first temperature to a
second temperature.
Inventors: |
Rebres; Robert P. (Fairport,
NY) |
Assignee: |
Xerox Corporation (Stamford,
CT)
|
Family
ID: |
23888683 |
Appl.
No.: |
05/475,689 |
Filed: |
June 3, 1974 |
Current U.S.
Class: |
399/45; 219/216;
399/69; 271/154 |
Current CPC
Class: |
G03G
15/6502 (20130101); G03G 15/2003 (20130101) |
Current International
Class: |
G03G
15/20 (20060101); G03G 15/00 (20060101); G03G
015/00 () |
Field of
Search: |
;355/14,133
;354/174,275,276,284 ;271/145,154,171 ;219/216 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Braun; Fred L.
Attorney, Agent or Firm: Fleischer; H. Ralabate; J. J.
Green; C. A.
Claims
What is claimed is:
1. An electrophotographic printing machine of the type having a
fusing apparatus to substantially permanently affix a powder image
to a sheet of support material, including:
means for separating and advancing successive sheets of support
material from a stack thereof;
means for supporting a first stack of sheet material in said
separating and advancing means;
removable means for supporting a second stack of sheet material in
said separating and advancing means; and
means, responsive to insertion of said second stack supporting
means in said separating and advancing means, for automatically
switching the fuser temperature set-point from a first temperature
for the first stack of sheet material to a second temperature for
the second stack of sheet material.
2. A printing machine as recited in claim 1, wherein said switching
means controls the number of copies made from an original document
disposed in the printing machine for each energization thereof.
3. A printing machine as recited in claim 1, wherein said first
stack supporting means includes:
a frame member; and
a base plate mounted pivotably on said frame member and arranged to
hold the first stack of sheet material thereon.
4. A printing machine as recited in claim 3, wherein said second
stack supporting means includes:
a bottom member positioned on the first stack supported on said
base plate, said bottom member having a generally planar surface
arranged to support the second stack of sheet material thereon;
a first side member secured to and extending in a direction
substantially normal to said bottom member; and
a protuberance secured to and extending in an outwardly direction
from said first side member, said protuberance being adapted to
actuate said switching means to change the fuser temperature
set-point from the first temperature to the second temperature.
5. A printing machine as recited in claim 4, wherein the first
stack of sheet material includes a plurality of fibrous sheets.
6. A printing machine as recited in claim 4, wherein the second
stack of sheet material includes a plurality of substantially
transparent non-fibrous sheets.
7. A printing machine as recited in claim 4, further including:
a back member secured to said bottom member and extending in an
upwardly direction substantially normal thereto;
a top member secured to said back member with the leading marginal
portion thereof hinged to the rear portion thereof, said top member
extending in a direction substantially parallel to said bottom
member; and
a front member hinged to the leading marginal portion of said top
member and extending in a downwardly direction substantially normal
thereto.
8. A printing machine as recited in claim 7, further including a
second side member secured to and extending in a direction
substantially normal to said bottom member and the rear portion of
said top member opposed from said first side member, said second
side member extending over a portion of said bottom member and the
rear portion of said top member.
9. A printing machine as recited in claim 1, wherein said
separating and advancing means includes:
a frame member;
a retard roller mounted eccentrically on said frame member;
biasing means for resiliently urging said retard roller to pivot
from an inoperative position spaced from one surface of an
advancing sheet to an operative position in contact therewith;
and
a rotary driven feed roller having a first portion of the
circumferential surface thereof engaging the other surface of the
advancing sheet and a second portion of the circumferential surface
engaging the circumferential surface of said retard roller disposed
in the operative position thereof prior to the advancing sheet
being interposed therebetween, said feed roller being adapted to
advance the sheet into the nip defined by said feed roller and said
retard roller to prevent multiple sheet feeding.
Description
This invention relates generally to an electrophotographic printing
machine, and more particularly, to a cassette for holding a stack
of sheet material therein.
A typical electrophotographic printing machine employed in a
business office is provided with cut sheets of support material.
These sheets are utilized as an image receiving member for the
printing machine. Although paper is the most commonly employed
sheet material, certain non-fibrous plastic sheets characterized
generally by having a high surface gloss and a smooth surface
finish are increasingly being employed. These non-fibrous sheets
are frequently more durable than paper and, when transparent, have
utility as transparencies, i.e. a conventional projector may
project images therefrom onto a screen.
In general, the sheet material is of a pre-selected size and
advances through the printing machine, one sheet at a time, for
suitable processing therein. Inasmuch as copies may be made at high
speeds, it is advantageous to stack a pile of sheets in the
printing machine feeding mechanism which advances the sheets one at
a time therefrom. The sheets are advanced until the stack thereof
is depleted, whereupon the operator refills the machine with a new
stack of sheets. However, it has been found that when a non-fibrous
sheet material is substituted for conventional paper, operational
difficulties frequently occur. For example, the fusing temperature
in the case of a transparency or a thermoplastic material is
different from that of a sheet of paper. This results in the
operator having to reset the fuser temperature set-point manually.
In addition, it is frequently difficult to furnish a large stack of
sheet material and place it in the sheet feeding apparatus when a
stack of paper has been previously disposed therein. In the past,
this has not been a significant problem in that the utilization of
transparencies has been somewhat limited. However, with the advent
of multicolor printing, these problems have become somewhat more
significant.
In a multi-color electrophotographic printing machine, it is highly
desirable to have the capability of creating multi-color
transparencies. Transparencies of this type are frequently employed
for display purposes, i.e. by projection onto screens for seminars
or business meetings. Hence, there is a continuing need for
trouble-free maintenance and supplying of thermoplastic
transparencies particularly in the case of multi-color
electrophotographic printing machines.
Accordingly, it is the primary object of the present invention to
provide an improved cassette for use in a sheet feeding apparatus
of a multi-color electrophotographic printing machine.
SUMMARY OF THE INVENTION
Briefly stated, and in accordance with the present invention, there
is provided a cassette for holding a stack of sheet material in a
sheet feeding apparatus of an electrophotographic printing machine.
The printing machine includes a fuser having at least two
temperature set points.
Pursuant to the present invention, the cassette includes a bottom
member positioned in the sheet feeding apparatus and having a
generally planar surface arranged to support the stack of sheet
material thereon. A protuberance is secured to and extends in an
outwardly direction from a marginal region of the bottom member.
Means are provided for switching the fuser temperature set-point.
The switching means is in communication with the protuberance of
the bottom member and the fuser. The protuberance is adapted to
actuate the switching means to change the fuser temperature
set-point from a first temperature to a second temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become
apparent upon reading the following detailed description and upon
reference to the drawings, in which:
FIG. 1 illustrates a schematic perspective view of an
electrophotographic printing machine incorporating therein the
cassette of the present invention;
FIG. 2 depicts a schematic perspective view of the FIG. 1 printing
machine sheet feeding apparatus with the cassette of the present
invention disposed therein;
FIG. 3 shows a schematic perspective view of the cassette
controlling the FIG. 1 printing machine fuser temperature
set-point; and
FIG. 4 depicts a perspective view of the cassette opened with the
sheet material extending outwardly therefrom.
While the present invention will be described in connection with a
preferred embodiment thereof, it will be understood that it is not
intended to limit the invention to that embodiment. On the
contrary, it is intended to cover all alternatives, modifications,
and equivalents as may be included within the spirit and scope of
the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
A general understanding of an electrophotographic printing machine,
in which the present invention may be incorporated, is had by
referring to FIG. 1. FIG. 1 schematically illustrates the various
components of a printing machine adapted to produce color copies
from a multi-colored original document. Continued reference will
hereinafter be made to the drawings wherein like reference numerals
have been used throughout to designate like elements.
Turning now to FIG. 1, the printing machine depicted therein
employs a drum 10 with a photoconductive surface 12 entrained about
and secured thereto. Drum 10 is mounted rotatably within the
machine frame (not shown) and is adapted to rotate in the direction
of arrow 14. A timing disc (not shown) is mounted in the region of
one end of the shaft of drum 10. In association with the timing
disc is a photosensor and a light source. The timing disc includes
a plurality of slits in the periphery thereof with the remainder
being opaque. The disc is interposed between the light source and
the photosensor to act as a light chopper periodically exciting the
photosensor to control the various processing stations within the
printing machine.
As drum 10 rotates in the direction of arrow 14, it passes through
a plurality of processing stations. These processing stations will
be described briefly hereinafter.
Initially, drum 10 rotates in the direction of arrow 14 to move
photoconductive surface 12 through charging station A. At charging
station A, a corona generating device, indicated generally at 16,
produces a spray of ions with charge photoconductive surface 12 to
a relatively high, substantially uniform potential. To achieve
this, corona generating device 16 extends in a generally transverse
direction across photoconductive surface 12. A suitable corona
generating device is described in U.S. Pat. No. 2,778,946 issued to
Mayo in 1957.
Thereafter, drum 10 rotates to exposure station B where the charged
photoconductive surface 12 is irradiated with a color-filter light
image of the original document. A moving lens system, generally
designated by the reference numeral 18, and a color-filter
mechanism, shown generally at 20, are located at exposure station
B. U.S. Pat. No. 3,062,108 issued to Mayo in 1962 is one type of
moving lens system suitable for use in the foregoing
electrophotographic printing machine. As illustrated in FIG. 1,
original document 22 is supported stationarily face down upon
transparent viewing platen 24. Successive incremental areas of
original document 22 are scanned by lamp assembly 26 and lens
system 18 moving in a timed relationship with drum 10. This
scanning process produces a flowing light image of original
document 22 on photoconductive surface 12. During exposure, filter
mechanism 20 interposes selected color filters into the optical
light path of lens 18. Each filter operates on the light rays
passing through lens 18 to record an electrostatic latent image on
photoconductive surface 12 corresponding to a preselected spectral
region of the electromagnetic wave spectrum, hereinafter referred
to as a single color electrostatic latent image.
After the single color electrostatic latent image is recorded on
photoconductive surface 12, drum 10 rotates to development station
C. At development station C, there are located three individual
developer units, generally designated by the reference numbers 28,
30 and 32, respectively. Each of the foregoing developer units is
of the type described in copending application Ser. No. 255,259
filed on May 19, 1972 now U.S. Pat. No. 3,854,449. As disclosed
therein, developer units 28, 30 and 32, respectively, are all of a
magnetic brush variety. A typical magnetic brush system employs a
magnetizable developer mix having carrier granules and toner
particles therein. This developer mix is continually brought
through a directional flux field to form a brush thereof.
Development is achieved by bringing the electrostatic latent image
recorded on photoconductive surface 12 into contact with the brush
of developer mix. Each of the respective developer units, i.e. 28,
30 and 32, contain discretely colored toner particles corresponding
to the complement of the spectral region of the wavelength of light
transmitted through filter 20. For example, a green filtered
electrostatic latent image is rendered visible by depositing green
absorbing magenta toner particles thereon. Similarly, blue and red
electrostatic latent images are developed with yellow and cyan
toner particles, respectively.
Once the single color electrostatic latent image is developed, drum
10 rotates to transfer station D. At transfer station D, the single
color powder image adhering electrostatically to photoconductive
surface 12 is transferred to a sheet of final support material 34.
A suitable final support material may be plain paper, or a
thermoplastic sheet, amongst others. A bias transfer roll, shown
generally at 36, recirculates support material 34 and is
electrically biased to a potential of sufficient magnitude and
polarity to electrostatically attract toner particles from
photoconductive surface 12 to sheet 34. U.S. Pat. No. 3,612,677
issued to Langdon, et al. in 1971 describes a suitable electrically
biased transfer roll. Transfer roll 36 rotates in synchronism with
drum 10 enabling a plurality of successive single color toner
powder images to be transferred to sheet 34 in registration with
one another. As shown in FIG. 1, transfer roll 36 rotates in the
direction of arrow 38. Sheet 34 is advanced either from a stack 40
housed in the sheet feeding apparatus, indicated generally by the
reference numeral 42, or from a cassette 44 disposed therein. The
sheet feeding apparatus 42 and the cassette 44 will be discussed
hereinafter in greater detail. Feed roller 46 in operative
communication with retard roller 48 advances the uppermost sheet
into chute 50. The sheet then moves into the nip between register
rollers 52. Register rollers 52 align and forward the sheet to
gripper fingers 54. Gripper fingers 54 are mounted on transfer roll
36 and secure releasably thereto the sheet of support material for
movement therewith in a recirculating path.
After a plurality of toner powder images have been transferred to
sheet 34, gripper fingers 54 release sheet 34 and stripper bar 56
separates sheet 34 from transfer roll 36. Sheet 34 is stripped from
transfer roll 36 and transported on endless belt conveyor 58 to
fixing station E.
At fixing station E a fuser, indicated generally at 60, permanently
affixes the multi-layered toner powder image to sheet 34. Fuser 60
and the operation thereof in conjunction with the cassette 44 will
be described hereinafter in greater detail with reference to FIG.
3. After the fusing process, sheet 34 is advanced by endless belt
conveyors 62 and 64 to a catch tray 66 for subsequent removal
therefrom by the machine operator.
Although a preponderance of the toner particles are transferred to
sheet 34, invariably some residual toner particles remain on
photoconductive surface 12 after the transfer thereof. These
residual toner particles are removed from drum 10 as it passes
through cleaning station F. At cleaning station F, the residual
toner particles are initially brought under the influence of a
cleaning corona generating device (not shown) adapted to neutralize
the electrostatic charge remaining on photoconductive surface 12
and the residual toner particles. These neutralized toner particles
are then cleaned from photoconductive surface 12 by a rotatably
mounted fibrous brush 68 in contact therewith. A suitable brush
cleaning device is described in U.S. Pat. No. 3,590,412 issued to
Gerbasi in 1971.
It is believed that the foregoing description is for the purposes
of the present application to illustrate the general operation of
an electrophotographic printing machine embodying the teachings of
the present invention therein.
Referring now to FIG. 2, sheet feeding apparatus 42 is depicted
therein in detail. Sheet feeding apparatus 42 includes a sheet
tray, indicated generally by the reference numeral 70, mounted
pivotably on frame 72 secured fixedly to the printing machine.
Sheet tray 70 pivots in a clockwise direction so that the leading
marginal edge portion of the uppermost sheet 74 engages feed roller
46. A pair of springs, (not shown) suitably mounted to tray 70
resiliently urge tray 70 to pivot in the clockwise direction. Tray
70 includes a base plate 76 having a generally planar surface for
supporting stack 40 thereon. Stack 40 is positioned both
longitudinally and laterally on base plate 76 by means of margin
guides 78 and 80. Margin guide 80 is mounted movably on base plate
76 and adjusts the stack so that the side opposed therefrom is in
registration with stationary wall 82. In this manner, the sheet
feeding apparatus is adjustable to accomodate various width stacks
thereon. Similarly, margin guide 78 is adjustable lengthwise so as
to align and position the stack on base plate 76. Feed roller 46 is
driven by a suitable motor (not shown) in the direction of arrow 84
to advance the uppermost sheet 74 in the direction of arrow 86.
Shaft 88 secures feed roller 46 fixedly to the printing machine.
Feed roller 46 is preferably arranged only to rotate in the
direction of arrow 84 and does not articulate in any manner but
remains stationary, the uppermost sheet of the stack being brought
into engagement therewith. Feed roller 46 has a first portion 88 of
the circumferential surface thereof engaging retard roller 48 and a
second portion 90 of the circumferential surface thereof engaging
sheet 74. As positioned, feed roller 46 has first portion 88
engaging retard roller 48 substantially simultaneously with second
portion 90 engaging sheet 74. Retard roller 48 is mounted
eccentrically on shaft 92. Shaft 92 is mounted rotatably within the
printing machine frame and is adapted to pivot retard roller 48
from a first position spaced from feed roller 46 to a second
position in engagement therewith. Biasing means or spring 94 pivots
handle 96 in the direction of arrow 98. Handle 96 is secured to one
end portion of shaft 92. In this way, retard roll 48 is pivoted
into engagement with feed roller 46. Spring 94 is secured to handle
96 and attached fixedly to frame 72. Preferably, spring 94 has 7
coils and an initial tension of about 0.5 pounds with an outer
diameter of 0.5 inches. The spring wire has a thickness of about
0.016 inches. Handle 100 is secured to the other end portion of
shaft 92 and adapted to be manually moved in the direction of arrow
102 to disengage retard roller 48 from feed roller 46. Cassette 44
is shown positioned on top of stack 40 with feed roller 46 in
engagement with the sheet material extending outwardly from
cassette 44. In this way, feed roller 46 advances successive sheets
from cassette 44 rather than from stack 40. The detailed structure
of cassette 44 will be discussed hereinafter with reference to
FIGS. 3 and 4.
Referring now to FIG. 3, cassette 44 includes a bottom member 104
with a back member 106 secured to and extending in an upwardly
direction therefrom. A first side member 108 is normal to bottom
member 104 and back member 106 and is secured to both of the
foregoing. A second side member 110 extends over a portion of
bottom member 104 and is secured thereto in a normal direction. Top
member 112 is substantially parallel to bottom member 104 and is
secured to side members 108 and 110 as well as back member 106.
Front member 113 is secured to the leading marginal portion 112a of
top member 112 and extends in a downwardly direction substantially
normal thereto. Leading portion 112a is hinged to rear portion 112b
of top member 112. Similarly, front member 113 is hinged to leading
portion 112a and is secured releasably to bottom member 104 when in
a closed position, by a suitable latch (not shown). When in the
opened position, leading portion 112a is flipped back over rear
portion 112b and lies substantially flat thereon. Front member 113
also lies substantially flat on rear portion 112b when cassette 44
is in the opened position. Top member 112, side member 108, side
member 110, bottom member 104, back member 106 and front member 113
together define a substantially box-shaped container for storing a
stack of sheets therein.
Protuberance 114 is secured to side member 110 and extends in an
outwardly direction therefrom. When the leading top portion 112a
and front member 113 are pivoted to the opened position it defines
an open ended box. In this way, the stack may be encompassed within
cassette 44 and the leading top portion 112a of top member 112 and
front member 113 pivoted back to expose the leading marginal
portions of the stack contained therein. Hence, when a stack of
transparencies 116 are to be employed in the printing machine,
cassette 44 is placed on top of stack 40 and the leading edge
portion 112a of top member 112 and front member 113 are pivoted to
the opened position exposing the leading edge portion of stack 116
(FIG. 4).
When cassette 44 is disposed in sheet feeding apparatus 42,
protuberance 114 engages switch 118. Switch 118 is mounted on
stationary side wall 82 of sheet feeding apparatus 42. Switch 118
is electrically connected to fuser 60 and adapted to change the
mode of operation thereof from a first temperature to a second
temperature. Thus, when cassette 44 is positioned in sheet feeding
apparatus 42, switch 118 is actuated. This changes the temperature
set point of fuser 60 so as to be optimum for the sheet material
contained within cassette 44. Additionally, switch 118 controls the
sheet feeding apparatus so that single sheets are advanced from
cassette 44 each time the operator presses the print button. This
prevents the automatic multiple copying of a single original
document. Thus, in this mode of operation, multiple copying is
prevented and for each copy the print button must be actuated.
Fuser 60 includes a radiant energy source and an auxiliary heater.
Initially, the radiant energy source operates at a full power of
about 1750 watts. When the endless belt conveying the support
material is raised to a pre-selected temperature condition which
may range from about 390.degree.F to about 420.degree.F, depending
upon humidity conditions, the radiant energy source is
de-energized. Fuser 60 is maintained at a standby temperature by an
auxiliary heater disposed beneath the endless conveyor for
transporting the sheet of support material. As a sheet of support
material enters fuser 60, the machine logic energizes the radiant
energy source at the upper power level (in this case 1750 watts)
and de-energizes the auxiliary heater. As the sheet of support
material exits fuser 60, the machine control logic energizes the
auxiliary heater and de-energizes the radiant energy source. This
type of control cycle continues as long as the thermostat
positioned in the air space between the outer and inner reflectors
of the radiant energy source indicate a temperature below about
440.degree.F. If, however, the temperature exceeds about
440.degree.F, the radiant energy source is energized at a lower
power level (in this case 1250 watts) when the sheet of support
material enters fuser 60. In addition thereto, the auxiliary heater
remains energized. As the sheet of support material exits fuser 60,
the machine control logic de-energizes the radiant energy source
while the auxiliary heater remains energized. When cassette 44 is
disposed on sheet feeding apparatus 42, protuberance 114 actuates
switch 118 which de-energizes the radiant energy source and
maintains the auxiliary heater activated. Thus, fuser 60 has the
temperature set point thereof changed from a first temperature to
second temperature which is substantially optimum for permanently
affixing the toner powder image to a substantially transparent
sheet of thermoplastic material. The detailed description of fuser
60 and the control circuitry associated therewith is described in
U.S. Pat. No. 3,781,516 issued to Tsilibes, et al. in 1973, the
disclosure of which is hereby incorporated into the present
application.
Referring now to FIG. 4, there is shown cassette 44 with the
leading edge portion 112a pivoted to the opened position so that
stack 116 extends outwardly therefrom. As shown therein, leading
edge portion 112a is secured hingedly to the remaining portion 112b
of top member 112. Once again, side member 108 is secured to bottom
member 104 and portion 112b of top member 112. Thus cassette 44
defines a substantially rectangular chamber adapted to house a
stack of transparencies 116 therein. The leading portion 112a
thereof and front member 113 are flipped back over rear portion
112b exposing the leading portion of stack 116.
In recapitulation, the cassette of the present invention is adapted
to regulate the temperature of the fusing apparatus. Thus, fuser 60
may be arranged to permanently affix the toner powder image formed
on a sheet of paper at a first temperature set point, whereas a
second temperature set point is required for a transparency. Hence,
when cassette 44 is disposed in sheet feeding apparatus 42 it
actuates switch 118 which, in turn, resets the temperature set
point of fuser 60. Hence, the temperature set point of fuser 60 is
adjusted from a first set point to a second set point substantially
optimum for permanently affixing toner powder images to sheets of
thermoplastic material.
Thus, it is apparent that there has been provided, in accordance
with this invention, a cassette for regulating the temperature set
point of a fusing apparatus in accordance with the type of sheet
material being employed in the electrophotographic printing
machine. This cassette fully satisfies the objects, aims and
advantages set forth above. While this invention has been described
in conjunction with specific embodiments thereof, it is evident
that many alternatives, modifications, and variations will be
apparent to those skilled in the art in light of the foregoing
description. Accordingly, it is intended to embrace all such
alternatives, modifications and variations that fall within the
spirit and broad scope of the appended claims.
* * * * *