Read/write bar for multi-mode reproduction machine

A dual mode reproduction machine or copier incorporating a full width read/write bar having at least one linear array of LEDs for selectively illuminating and scanning a document original in a read mode or exposing the copier photoreceptor in a write mode. A Selfoc lens array provides a lens element for focusing each LED, the rear/write bar and lens array being combined in a unitary structure mounted for selective movement between a read and write position.

The invention relates to a multi-mode reproduction machine, and more 
particularly to a full width image read/write bar for use in machines of 
this type. 
Typical reproduction machines such as xerographic type copiers may be 
classified as single mode machines in that machines of this type commonly 
have just one function, namely to produce copies from document originals. 
And, while machines of this type may come in a variety of designs, operate 
at various speeds, and incorporate various and sundry aids such as 
document handlers, they remain a single mode machine. 
Recently, interest has arisen in multi-mode machines, namely, reproduction 
machines or copiers that in addition to or in lieu of performing the usual 
copying function also are capable of reading a document image and 
converting the image to electrical signals or pixels, which then may be 
stored in memory, transmitted to a remote site via a suitable data 
communication channel, etc. And as a further supplemental or alternate 
mode, capable of writing images on the machine imaging member in 
accordance with an image signal or pixel input from a suitable source 
which may as in the case of the reading mode discussed above, comprise a 
memory, data communication channel, etc. However, attempts to provide 
machines combining one or both of these additional operating functions or 
modes have been handicapped by problems of greatly increased expense and 
complexity, problems which have mitigated against the commercial 
acceptance of machines of this type. For example, one type of image 
writing system requires a high intensity beam of light which normally 
requires the use of a relatively expensive laser. But further, a 
relatively sophisticated optical system is needed; an optical system which 
requires in addition to the usual lenses and mirrors, a device such as a 
rotating polygon to scan the light beam across the machine imaging element 
and a modulator such as an acousto-optical type modulator to modulate the 
beam in accordance with the content of the image signal or pixel input. 
Coupled with this is the need for complex and expensive electronic 
circuitry for operating the writing mechanism in timed synchronization 
with the reproduction machine or copier with which it is associated which 
often requires the use of large amounts of relatively expensive memory. 
The invention seeks to permit a simpler, less expensive multi-mode 
apparatus capable of reading a document original and converting the image 
to electrical signals or pixels, or of writing image copies in response to 
an image signal input, and provides a combined document reading, 
illuminating, and writing means for either scanning a document to provide 
image signals representative of the document image or scanning an imaging 
member to expose the imaging member in accordance with an image signal 
input and write images represented by the image signal input on said 
imaging member, comprising in combination: a substrate; plural light 
emitting and light sensing scanning elements on the substrate, the 
scanning elements being arranged on the substrate in at least one linear 
array capable of either scanning a document or scanning the imaging 
member; and control means for operating first ones of the elements as 
light emitters for illuminating a line-like portion of the document and 
the remaining second ones of the elements as image sensors for scanning 
the document illuminated portion and converting the document image to 
image signals or for operating both the first and second ones of the 
elements as selectively actuable light emitters for exposing the imaging 
member in accordance with the image signal input.

Referring to FIGS. 1 and 2, the dual function image read/write bar of the 
present invention, designated generally by the numeral 10, is thereshown 
in combination with a multi-mode copier or reproduction machine 12. As 
will appear, reproduction machine 12 is operable in a READ mode to scan a 
document original 11 disposed on viewing platen 16 and convert the 
document image to electrical signals or pixels, in a WRITE mode to expose 
imaging member 20 thereof in accordance with an image signal input to 
create image copies or reproductions. Reproduction machine 12 is a 
xerographic based system in which the imaging member 20 comprises a 
photoreceptor 22 in the form of a drum supported for rotation in a 
suitable housing or enclosure (not shown). A suitable motor (not shown) 
rotates drum 22 in the direction shown by the solid line arrow during 
operation of reproduction machine 12. A suitable corona charging device or 
corotron 24 is disposed in operative relationship with photoreceptor 22, 
corotron 24 serving to place a uniform electrostatic charge on 
photoreceptor drum 22 preparatory to exposure thereof. 
Photoreceptor 22 is exposed at an exposure station 25 downstream of 
corotron 24 in a manner to be more fully described hereinbelow, such 
exposure creating a latent electrostatic image on the surface of 
photoreceptor 22. Following exposure, the latent electrostatic image on 
photoreceptor 22 is developed by a suitable developer 26 illustrated 
herein as a magnetic brush developing roll 27. Magnetic brush developing 
roll 27 is rotatably disposed at a suitable developer housing 28, the 
lower portion of which forms a sump or reservoir 29 for a supply of 
developer material. A suitable developer loading device illustrated herein 
as a donor roll 31 serves to draw developer from sump 29 and load the same 
onto developing roll 27, the magnetic forces generated by suitable magnets 
internal of developing roll 27 (not shown) serving to attract and hold at 
least a portion of the developer material on the exterior surface of 
developing roll 27. As will be understood by those skilled in the 
xerographic arts, developer material may comprise a mixture of relatively 
large carrier beads and relatively smaller toner or ink particles, the 
toner adhering to and being carried on the relatively larger carrier beads 
through electrostatic forces. On disposition of developer material into 
operative relationship with photoreceptor 22, toner is attracted to the 
latent electrostatic image on the photoreceptor from developing roll 27 in 
proportion to the electrostatic forces to render the latent electrostatic 
image on photoreceptor 22 visible. 
Following development of the latent electrostatic image, the developed 
image is carried by photoreceptor 22 to transfer station 33 whereat the 
developed image is transferred from photoreceptor 22 to a suitable copy 
substrate material shown here as a sheet 34 of copy paper brought forward 
by a suitable copy sheet feeder 36 in timed relation to arrival of the 
developed image on photoreceptor 22 at transfer station 33. To facilitate 
transfer, a transfer corotron 35 is disposed opposite the photoreceptor at 
transfer station 33. The copy sheet 34 bearing the developed image is 
carried to a suitable fusing or fixing device (not shown) where the toner 
image is permanently adhered to the copy sheet 34. A cleaning station 38 
downstream of transfer station 33 serves to remove any leftover developing 
material on the photoreceptor 22 prior to making the next image. In the 
exemplary copier shown, a cleaning brush 39 is provided at cleaning 
station 38 for this purpose. 
Image read/write bar 10 comprises an elongated generally rectangular base 
or substrate 40, having an array of individual elements such as Light 
Emitting Diodes 42 (LEDs herein) arranged in a linear row 41 thereacross. 
Preferably, the width of substrate 40 in a cross scan direction (the X 
direction) is such that the length of the row 41 of LEDs 42 is 
substantially equal to the effective width of the photoreceptor 22. LEDs 
42 are preferably integrated into and fabricated with LED control 75 
(shown in FIG. 3) on substrate 40 to form a unitary structure, the number 
of LEDs 42 per increment of length of substrate 40 being determinative of 
the image resolution achieved. 
A linear array lens 45 of gradient optical fibers or fiber lenses 46 is 
provided, there being one optical fiber 46 for each LED 42 on read/write 
bar 10. Lens array 45 is disposed in predetermined spaced relationship to 
the surface of read/write bar 10 and LEDs 42, the optical fibers 46 of 
lens array 45 being optically aligned with the LEDs 42 associated 
therewith. Optical fibers of the type referred to herein are produced 
under the tradename "SELFOC," registered in Japan and owned by Nippon 
Sheet Glass Co., Ltd. To assure a predetermined spatial relationship 
between read/write bar 40 and lens array 45, suitable frame elements 48 
are used to rigidly couple read/write bar 40 with lens array 45 to form a 
combined read/write bar-lens array structure 50. To enable the read/write 
bar-lens array structure 50 to be selectively moved between read and write 
positions as will appear, the read/write bar-lens array 50 is supported 
for pivotal movement as by means of pins 51 between photoreceptor 22 and a 
slit-like document scanning aperture 60 in an adjoining document 
supporting platen 16. One or more torsion type springs 54 serve to bias 
the structure 50 to one position (illustrated herein as the image read 
position). A suitable operator such as solenoid 56 is drivingly coupled to 
the read/write bar-lens array structure 50, solenoid 56 being operative 
when energized to rotate the structure 50 through an arc of approximately 
90.degree. to place the read/write bar-lens array structure 50 to a second 
write position. Adjustable stops 57, 58 limit rotation of the structure 50 
and permit preadjustment of the position of the structure 50 in proper 
axial alignment with scan aperture 60 and exposure station 25 for optimum 
operation in both the read and write modes. 
Platen 16 forms a relatively flat or planar surface 64 for supporting the 
document 11 to be scanned, scanning taking place through the slit-like 
scanning aperture 60 in platen 16. The longitudinal axis of scanning 
aperture 60 extends in a direction paralleling the scan axis of read/write 
bar 10 (i.e. the X direction), the longitudinal dimension of aperture 60 
being equal to or slightly greater than the length of the LED row 41 while 
the dimension of the aperture 60 along the scan axis (the Y direction) is 
sufficient to permit at least one line of the document to be viewed at a 
time by read/write bar 10. 
To advance the document 11 to be scanned across platen 16 and scanning 
aperture 60, a suitable feeder illustrated herein as a constant velocity 
transport (CVT) document feed roll 70 is provided. Platen 16 and feed roll 
70 cooperate to form a nip between which the document is fed. Document 
feed roll 70, which is preferably disposed adjacent one edge of aperture 
60, is driven by a suitable motor such as step motor 72. 
Referring now to FIG. 3, during operation in the READ mode, read/write bar 
10 functions as both a scanning array to read the portion of document 
opposite scanning aperture 60 and as an illumination source for 
illuminating scanning aperture 60 and the portion of the document 11 
thereover. To effectuate this and in a preferred embodiment, alternate 
LEDs 42-1, 42-3, . . . 42-N-1 are coupled to a suitable voltage source 115 
such that LEDs 42-1, 42-3, . . . 42-N-1 are energized continuously during 
operation in the READ mode to illuminate aperture 60 and the portion of 
document thereover. The remaining LEDs 42-2, 42-4, . . . 42-N function as 
light detectors to scan the portion of the document 11 illuminated by LEDs 
42-1, 42-2, . . . 42-N-1 and convert the image portion viewed to 
electrical signals or pixels representative of the image grey levels. 
Other LED illumination sequences may be envisioned as for example that 
shown in the embodiment of FIG. 4 where one LED (42-2, 42-5, . . . 42-N-1) 
serves to provide illumination for the LEDs (42-1, 42-3; 42-4, 42-6; . . . 
42-N-2, 42 N) on either side thereof. 
During operation in the WRITE mode, the entire row 41 of LEDs 42 are 
utilized as selectively actuatable light sources to expose the 
photoreceptor 22, the individual LEDs actuated at any one time being a 
function of the image signal input. 
Referring particularly to FIG. 5, an LED control 75 is provided for 
operating the machine 12 in either the image READ or WRITE mode. LED 
control 75 comprises a matrix system for selectively operating LEDs 42 as 
appropriate in either read the document 11 or write images on 
photoreceptor 22. Pursuant thereto, LEDs 42 are segregated into groups 
77-1, 77-2, . . . 77-N of an equal number of LEDs each, with a pair of 
group control switches 78-1, 78-1'; 78-2, 78-2'; . . . 78-N, 78-N' for 
every other LED that comprises each LED group 77-1, 77-2, . . . 77-N. 
Individual LED control switches 80-1, 80-2, . . . 80-N are provided, the 
number of control switches being equal to the number of LEDs that comprise 
the read/write bar 10. 
A pair of LED control shift registers 85, 85' have successive output stages 
coupled through OR function gates 82 and control lines 86-1, 86-3, . . . 
86-N-1 and 86-2, 86-4, . . . 86-N respectively to the control terminals of 
LED control switches 80-1, 80-3, . . . 80-N-1 and 80-2, 80-4, . . . 80-N 
respectively. Shift registers 85, 85' control actuation of the LED control 
switches 80-1, 80-2, . . . 80-N in timed sequence in response to clock 
signals .theta. output by a clock 94 during the image WRITE mode and LED 
control switches 80-2, 80-4, . . . 80-N only during the image READ mode. 
During the image READ mode, LED control switches 80-1, 80-3, . . . 80-N-1 
are held activated to permit LEDs 42-1, 42-3, . . . 42-N-1 to be 
continuously energized to illuminate the document being scanned. 
A LED group control shift register 95 has successive output stages thereof 
coupled to LED group control switches 78-1, 78-1'; 78-2, 78-2', . . . 
78-N, 78-N', control signals output by shift register 95 serving to 
actuate LED group control gates 78-1, 78-1', 78-2, . . . 78-N in timed 
succession to enable the indivdual LED groups 77-1, 77-2, . . . 77-N 
associated therewith. LED group control shift register 95 is driven by 
clock signals .theta..sub.2 which are a fraction of the clock signals 
.theta..sub.1 used to control actuation of the individual LED control 
switches 80-1, 80-2, . . . 80-N. Clock signals .theta..sub.2 are derived 
from clock signals .theta..sub.1 through divide by n circuit 99, it being 
understood that the ratio of clock pulses .theta..sub.1 to .theta..sub.2 
and the setting of divide by n circuit 99 is proportional to the number of 
LEDs 42 in each LED group 77-1, 77-2, . . . 77-n. 
A suitable multi-section mode selector, illustrated herein in the form of 
switch 100, is provided to permit the operator or user to select the 
operating mode desired, either READ or WRITE mode. Section 100-1 of 
selector switch 100 controls energization of document feeder motor 72 and 
reproduction machine 12 through lines 102, 104 respectively, and clock 94 
through OR function gate 106. Additionally, selector switch section 100-1 
controls operation of solenoid 56 through line 110. Selector switch 
section 100-2 couples LED group control switches 78-1', 78-2', . . . 78-N' 
to the image signal output line 112 when the image READ mode is selected 
and couples LED group control switches 78-1', 78-2', . . . 78-N' to 
voltage source 115 when the image WRITE mode is selected. LED group 
control switches 78-1, 78-2, . . . 78-N are coupled to voltage source 115 
through line 116. Selector switch section 100-3 selectively couples the 
other side of LED circuit 75 to either ground or a suitable source of 
video image signals designated herein by the numeral 120. As will be 
understood by those skilled in the art, image signal output line 112 may 
be coupled to any suitable image user such as a memory, communication 
channel, etc. Similarly, image signal source 120 may comprise memory, 
communication channel, image reader, etc. 
To permit LEDs 42-1, 42-3, . . . 42-N-1 to be operated continuously during 
the image READ mode and serve as the source of document illumination for 
the remaining LEDs 42-2, 42-4, . . . 42-N of read/write bar 10, OR 
function gates 117 are provided in the control line to LED group control 
switches 78-1, 78-2, . . . 78-N, one input terminal of gates 117 being 
coupled to alternate output stages of shift register 95 through lines 96 
and switches 124 of selector switch section 100-4, and the other input 
terminal being coupled by line 118 through switch 123 of selector switch 
section 100-4 to a suitable steady state signal source 119. 
OR function gates 82 are provided in the control lines to LED control gates 
80-1, 80-3, 80-N-1, gates 82 having one input coupled by lines 86 to the 
output side of shift register 85' while the other input terminal of gates 
82 is coupled by line 118' to the output side of selector switch section 
100-4. Switch 122 of selector switch section 100-4 is provided in the 
clock line to shift register 85. 
OPERATION 
Referring to FIGS. 1-6, where operation in the READ mode is desired, 
selector switch 100 is set to the solid line position shown in the 
drawings. In this operational mode, LEDs 42-2, 42-4, . . . 42-N function 
as light detectors to output an electrical signal or pixel, the potential 
of which reflects the grey level of the image portion viewed while LEDs 
42-1, 42-3, . . . 42-N-1 function as light sources to illuminate the 
portion of document 11 opposite scanning aperture 60. In this setting, 
selector switch section 100-1 enables document feed motor 72 so that on a 
demand for image signals, the document 11 is moved across scanning 
aperture 60. It is understood that the document 11 to be scanned is 
previously inserted into the nip formed by roll 70 and platen 16. Clock 94 
is enabled to scan LEDs 42-2, 42-4, . . . 42-N of read/write bar 10. 
Selector switch section 100-2 couples LED group control switches 78-1', 
78-2', . . . 78-N' to image signal output line 112 while selector switch 
section 100-3 couples LED circuit 75 to ground. Selector switch section 
100-4 couples (through gates 117) the control terminals of LED group 
control switches 78-1, 78-2, . . . 78-N and (through gates 82) LED control 
switches 80-1, 80-3, . . . 80-N to signal source 119. As a result, LED 
group control switches 78-1, 78-3, . . . 78-N and LED control switches 
80-1, 80-3, . . . 80-N are actuated to couple LEDs 42-1, 42-3, . . . 42-N 
to voltage source 115 to energize LEDs 42-1, 42-3, . . . 42-N and 
illuminate scanning aperture 60 and the portion of document 11 thereover. 
Concurrently, switches 122, 124 of selector switch section 100-4 
interrupts the clock signal input line to shift register 85 and the clock 
signal output lines 96 of register 95 to gates 117. 
It is understood that LED lens array 50 is normally disposed in the solid 
line position shown, springs 54 serving to retain LED lens array 50 
against locating stop 57 so that the individual LEDs 42 on read/write bar 
10 are focused by lens array 45 onto the scan aperture 60 and the document 
portion thereover. 
On demand for image signals following insertion of the document to be 
scanned into the nip formed by document feed roll 70 and platen 16, clock 
signals .theta..sub.1 from clock 94 operate LEDs 42-2, 42-4, . . . 42-N of 
read/write bar 10 to scan the document 11 line by line as the document is 
moved past scanning aperture 60 by roll 70, the clock pulses .theta..sub.1 
driving LED control shift register 85' and LED group control shift 
register 95 to successively couple LEDs 42-2, 42-4, . . . 42-N to output 
line 112, shift register 85' repeatedly actuating in succession 
individual LED control switches 80-2, 80-4, . . . 80-N while shift 
register 95 successively enables LED groups 77-1, 77-2, . . . 77-N in 
synchronism therewith to sample LEDs 42-2, 42-4, . . . 42-N across the 
scan line. It is understood that the remaining LEDs 42-1, 42-3, 42-N-1 of 
LED row 41 are energized continuously during this process to illuminate 
the document portion being scanned. The above process is repeated as each 
line of the document 11 is moved past scanning aperture 60 until scanning 
of the entire document 11 is completed at which time selector switch 100 
may be set to the inoperative or neutral position. 
Where it is desired to operate in the WRITE mode, selector switch 100 is 
moved to the dotted line position. In this operating mode, LEDs 42 
function as individually controlled light emitters effective to 
selectively expose photoreceptor 22 line by line in accordance with an 
image signal input. In this position, selector switch section 100-1 
enables reproduction machine 12 and clock 94, the latter to operate 
read/write bar 10 as will appear. At the same time switch section 100-1 
actuates solenoid 56 to move the read/write bar-lens array structure 50 
through an arc of approximately 90.degree. to the dotted line position 
shown wherein the row 41 of LEDs 42 on read/write bar 10 are focused onto 
photoreceptor 22 of reproduction machine 12 at imaging station 25. 
Selector switch sections 100-2 and 100-3 couple LED control 75 between 
voltage source 115 and image signal source 120 while switch 123 of 
selector switch section 100-4 interrupts input of the control signal from 
signal source 119 to circuits 82, 117. Switches 122, 124 of switch section 
100-4 couple the output of clock 94 to shift register 85 and the output 
stages of shift register 95 to the control gates of LED group control 
switches 78-1, 78-2, . . . 78-N. 
On input of image signals from image signal source 120, reproduction 
machine 12 and read/write bar 10 are actuated, LEDs 42 selectively 
exposing the charged photoreceptor 22 in accordance with the image signal 
output of signal source 120 to form a latent electrostatic image on 
photoreceptor 22. The image is developed by developer 26 and transferred 
to the copy sheet 34 at transfer station 33. In this mode, image signals 
from image signal source 120 are applied in succession to individual LEDs 
42 of read/write bar 10 through LED control switches 80-1, 80-2, . . . 
80-n on an LED group by group basis as determined by LED group control 
switches 78-1, 78-1'; 78-2, 78-2'; . . . 78-N; 78-N'. The selective 
actuation of LEDs 42 in accordance with the image signal content of the 
image signal output of signal source 120 creates a latent electrostatic 
image as described on photoreceptor 22 as described. 
In FIG. 7, an exemplary illumination profile is illustrated for the 
read/write bar 10 operating in the READ mode in accordance with the 
embodiment of FIGS. 1-3, 5 and 6. As is illustrated there, substantially 
uniform illumination is achieved to illuminate the document line for 
scanning purposes. 
While a single row 41 of LEDs 42 is disclosed herein, multiple parallel LED 
rows may be envisioned for reading and for writing multiple lines. In that 
event, during operation in the READ mode, the illuminating LEDs of one row 
may provide additional light for the reading LEDs of an adjacent row or 
rows which may be enhanced by changing, i.e. reversing the LED operating 
order. Further, the LEDs of one row may be axially offset from the LEDs of 
an adjacent row to enhance image reading and writing resolution, it being 
understood in the event that each LED row would process a portion of each 
line. 
While the invention has been described with reference to the structure 
disclosed, it is not confined to the details set forth, but is intended to 
cover such modifications or changes as may come within the scope of the 
following claims.