Apparatus for assisting manual placement of an original document on an exposure platen of copier

A system for assisting manual placement of odd-shaped original documents on the exposure platen of a copier or scanner includes a detection device disposed on an edge of the platen. The device includes a light source emitting a light beam substantially parallel to a surface of the platen, and a photosensor adapted to detect light resulting from the reflection of the light beam by an object on the surface of the platen. A main focus direction of the light source and a main focus direction of the photosensor intersect at a predetermined position on the surface of the platen.

The present invention relates to an apparatus which assists the manual 
placement of original documents on an exposure platen of a device which 
records the original document, such as a copier or a digital scanner. 
In the everyday use of copiers, the original documents which are copied can 
vary widely in size and in other qualities. Checks and receipts, for 
example, tend to be on paper which is not only small in size but 
relatively thin compared to typing paper. If a person wishes to make 
copies of a large number of small documents such as receipts and checks, 
one is typically required to place the original document manually on the 
exposure platen, because automatic document handling systems for originals 
are typically unsuited for circulating odd-shaped documents. Even if the 
documents are manually placed on the platen, it may be desirable to 
provide structures on the copier which assist on the manual placement of 
documents. One type of assistance may be in the form of a "stop" disposed 
along one edge of the platen, against which a person may gently urge the 
original document, so that the document is placed properly on the platen. 
The advantage of a stop is that one edge of the original document is 
aligned with an edge of the platen, and so the copy image will not be 
crooked on the copy sheet. 
In copying or scanning devices which use an original document handler, it 
is desirable that the surface around the platen be substantially flush 
with the platen so that the original documents moving through the document 
handler can easily slide into position relative to the platen. Thus, while 
a stop at the edge of a platen is useful for manual placement of 
documents, such a stop is likely to interfere with the use of an automatic 
original document handler. The "1090" series of copiers made by the Xerox 
Corporation includes a retractable stop, which is selectably disposable in 
a non-functional and in a functional position at the edge of the platen. 
In a functional position, the stop is raised from a position flush with 
the platen to a position protruding above the platen. This positioning of 
the stop is preformed by electro-mechanical means, such as using a 
solenoid. 
It is an object of the present invention to provide a system that will 
assist in the manual placement of documents on a platen by activating a 
stop when an original document is detected on the platen. The 
document-detection system according to the present invention may also be 
useful in the automatic selection of either magnification or copy sheet 
size in a copier. 
In the prior art, the article "Copy Sheet Size Selection" in IBM Technical 
Disclosure Bulletin Vol. 17, No. 9, February 1975, discloses a system in 
which a detector senses the leading and trailing edges of an original 
sheet circulating through an automatic original document handler, and then 
selects an appropriate copy sheet size based on measuring the original 
document. 
U.S. Pat. No. 4,541,713 discloses a document size-detecting device for a 
copying machine. A platen cover is provided with a plurality of colored 
portions. A light projector irradiates the surface of the platen, 
including the colored portions thereof, and light is reflected into 
light-receiving means which distinguish the colored portions from the rest 
of the surface. The light receiving means generates an output signal which 
is used to determine whether the signal is in the range corresponding to 
the wavelength of the colored portions. 
U.S. Pat. No. 4,588,289 discloses a document size reading device. The edges 
of the original are detected by an edge detector which is mounted on a 
moving unit which passes underneath the original. 
U.S. Pat. No. 4,707,111 discloses a copier wherein the copy sheets can be 
taken from a container or manually supplied. A first detector detects the 
size of the manually supplied copy sheets and a second detector detects 
the size of the copy sheets in the container. A controller controls the 
movement of the scanner (the exposure device) in accordance with the 
detection by the first and second detectors so that the scanning stroke 
length of the scanner is coordinated for the size of the copy sheet. 
U.S. Pat. No. 5,321,624 discloses an "insertion machine" having a plurality 
of document detectors, each detector being preset to a maximum allowable 
document-group-thickness measurement. A processing means determines the 
actual number of documents in a stack according to which detector was the 
first to be "tripped." 
U.S. Pat. No. 5,333,043 discloses an automatic original document feeder 
having a plurality of photosensors to coordinate the motion of sheets 
therethrough. 
According to one aspect of the present invention, there is provided an 
apparatus for assisting placement of an original document on an exposure 
platen. A photosensor is provided, having an effective detection zone 
extending substantially parallel to a surface of the platen. An extendible 
stop is disposed adjacent an edge of the platen, the stop being adapted 
for manual urging of an original document thereagainst. Control means 
extend the stop from a non-functional position to a functional position in 
response to a sheet being detected on the surface of the platen by the 
photosensor. 
According to another aspect of the present invention, there is provided an 
apparatus for assisting placement of an original document on an exposure 
platen, comprising a light source emitting a light beam substantially 
parallel to a surface of the platen, and a photosensor adapted to detect 
light resulting from the reflection of the light beam by a sheet on the 
surface of the platen. 
According to another aspect of the present invention, there is provided an 
apparatus for assisting placement of an original document on an exposure 
platen, comprising a light source emitting a light beam in a focus 
direction substantially parallel to a surface of the platen, and a 
photosensor adapted to detect light resulting from the reflection of the 
light beam by an object on the surface of the platen. A main focus 
direction of the photosensor intersects the focus direction of the light 
source at a predetermined position on the surface of the platen.

FIG. 1 is a simplified elevational view showing the basic elements of a 
copier with which the system of the present invention may be used. In the 
present application, the word "copier" is used in the broad sense of any 
device in which a hard-copy original is exposed and the information 
thereon recorded. As such, the word "copier" can mean the familiar 
light-lens copier, and also any digital system in which light reflected 
from the original document is recorded on a photosensitive device and 
converted into digital signals. 
A hard-copy original document is placed on a platen 10, where it is 
illuminated by light source 12, and the light reflected therefrom directed 
to an image recording device here indicated as 14. The reflected light 
from original document 10 may pass through any number of focusing and/or 
magnification means such as that indicated as 16. As shown in FIG. 1, the 
image recording device is shown as a photoreceptor drum, but could 
conceivably include any other means for recording and/or copying an image, 
such as a CCD or other photosensitive device, and could also be used to 
create a copy of the original image either by use of a photoreceptor, or 
other means such as an ink-jet printhead. 
When an image is copied by the copier, the copied image must be placed on a 
copy sheet. It is common in the art that a copier is able to provide at 
least two different types of copy sheet such as letter-size or legal-size, 
or else plain paper and letterhead, or two different colors of paper, or 
the copier may have an option of creating the copy image on a 
transparency. As shown in FIG. 1, there are provided two trays for 
different types of copy sheet. Either tray 20 and 22 includes feeder means 
such as motorized rolls 21 or 23 respectively which cause a sheet taken 
from the tray to pass through an apparatus where an image will be placed 
on the sheet, in this case photoreceptor 14. The sheets having copy images 
placed thereon are then fed out (:in an electrophotographic system) 
through a fuser such as 26, and deposited in an output tray 28. 
It can also be seen in FIG. 1 that there is provided, at the top of the 
copier, an original document handler generally indicated as 30. Various 
designs of automatic original document handlers are known in the art. 
Basically, the function of the original document handler is to cause a set 
of original documents loaded thereon to be sequentially indexed past the 
platen 10 for exposure. The actual operation of the automatic original 
document handler is not directly relevant to the present invention, but a 
common design is to place the document handler on a hinge such as 32 so 
that the document handler 30 can be swung out of the way when the document 
handler is not desired to be used. The platen 10 can then be directly 
accessed for manual placement of original documents. 
FIG. 2 is a plan view, looking down in the view marked 2 in FIG. 1, showing 
details of the platen 10 in an apparatus according to the present 
invention. It is common in commercially-available copiers and other 
scanners that an original document be positioned relative to a reference 
position on the platen so that the document will be properly placed 
relative to the exposing apparatus. Proper placement of an original 
document is particularly important when magnification is used. In the 
illustrated embodiment, it is intended that the corner of the original 
document be placed in the reference corner K as shown in the Figure; using 
a corner of the platen 10 as a reference point is a fairly common design 
in copiers and scanners. 
Along one edge of the platen 10 is a set of stops indicated as 40. Some of 
these stops are preferably located generally near reference corner K of 
the platen 10. Also disposed near the reference corner K opposite the 
stops 40 is a detector, such as indicated as 50, which is preferably in 
the form of a "passive infrared" or "passive IR" device. Device 50 is 
preferably of a type which is commercially available, such as, for 
example, the device known as OPB2731 made by Optek, Inc., or an equivalent 
device such as made by TRW. According to the present invention, there is 
provided (such as within the passive IR device 50) a light source which 
emits a light beam in a direction substantially parallel to the surface of 
the platen, and also a photosensor, (i.e., an infrared sensor) which is 
adapted to detect light resulting from the reflection of light from the 
light source by an object, such as a sheet, placed on the surface of the 
platen. It is common with infrared sensors to include a lens, pinhole, or 
similar element in combination with the sensor, so that the photosensor is 
in effect "focused" to detect light received along a specific direction. 
As described in the claims herein, the "detection zone" of the photosensor 
is the zone from which a photosensor is readily able to detect light of a 
certain type, and such a zone is typically in the form of a 
narrowly-defined area extending from the photosensor. 
According to the present invention, the photosensor should be focused in a 
direction substantially parallel to the surface of the platen. Turning to 
the example in FIG. 2, the device 50 includes a light source 52 and a 
photosensor 54, the focus direction of each being shown by the arrows 
emanating therefrom. As shown in the Figure, these focus directions 
preferably intersect at a location between 1/4 inch and one inch from the 
edge of the platen 10. In such a position, the device 50 is capable of 
detecting the presence of objects, such as an edge of a sheet bearing 
original images, on the surface of platen 10, and particularly in the area 
of intersection. 
The photodetector of the present invention is preferably disposed so that 
the light source 52 and photodetector 54 are focused as close to the 
surface of platen 10 as possible. FIG. 3 is a partial sectional view 
through the line 3--3 in FIG. 2, showing the preferred position of the 
device 50. There can also be seen in FIG. 3 one extendible stop 40. 
According to the present invention, this stop is extendible from a 
non-functional position, wherein it is essentially flush with the surface 
of platen 10, to a functional position, wherein it protrudes above the 
surface of the platen, as shown in phantom in the Figure. This extension 
of the stop 40 is carried out by electro-mechanical means generally 
indicated as 44, which could include, for example, a small electric motor, 
stepper motor, or solenoid, or any device which is capable of changing 
position in response to an electrical signal. When the electro-mechanical 
means 44 is activated, stop 40 (or any number of stops 40) extends to a 
functional position protruding above the surface of platen 10. Stop 40 in 
the functional position can assist in the manual positioning of an 
original document, such as a small receipt or check, so that it is 
straight on the platen and results in an image on the copy sheet which is 
properly aligned relative to the edges of the copy sheet. 
According to one embodiment of the invention, when the copier is in a mode 
for accepting manual placement of original documents on the platen 10, the 
detector 50 is adapted to detect sheets or other objects (such as a book) 
on the surface of platen 10. As shown in FIG. 3, the device 50 is 
operatively connected to a control means such as 60, which operatively 
connects the device 50 (or, more specifically, the photosensor 54 in 
device 50) to the electro-mechanical means 44 which ultimately cause stop 
40 to extend to the functional position. Thus, when a person places a 
document such as a check or a book manually on the surface of platen 10, 
the infrared light emitted from infrared source 52 will reflect from the 
edge of the sheet or book, and the reflected light will be detected by 
photosensor 54. 
When a detector such as device 50 is mounted relative to the platen 10 as 
shown, even single sheets may be detected because the direction of focus 
of both the light source 52 and photodetector 54 are as close as possible 
to being directly across the surface of platen 10. Typically, the 
protrusion of device 50 over the surface of platen 10 need be no more than 
1 mm, and preferably closer to 0.5 mm. When such a sheet or other object 
is detected, a signal will appear on photosensor 54, and this signal from 
photosensor 54 can be used to activate, through means known to one of 
skill in the art, control means 60, which in turn activates the 
electro-mechanical means 44, typically by applying an electrical signal 
thereto. When the stop 40 is extended to a functional position, the person 
manually placing documents on the platen 10 will then have the surface of 
stop 40 against which to gently urge the small document so that the 
document will be properly aligned with the edge of the platen 10. 
One variation to the present invention would be to provide, instead of a 
discrete emission/detection device such as 50, a more general source of IR 
or other light, such as a light bar emitting light evenly along one edge 
of platen 10, in combination with a set of pinpoint-size photodetectors 
along the same or another edge of platen 10. Such an arrangement may have 
advantages for specific document-handling applications. Another variation 
would be to provide an arrangement of fiber-optic devices to place the 
infrared source 52 and photosensor 54 in effect at the desired positions 
at the edge of the platen 10, even if the actual light source and detector 
are disposed elsewhere in the apparatus. That is, infrared source 52 and 
photosensor 54 could be placed on chips deep within the copier and 
fiber-optic cable could be used to optically connect the chips to the 
desired locations at the edge of the platen 10. 
It will also be noted in FIG. 3, that the control means 60 should interact 
with the position of the automatic original document handler indicated as 
30 in FIG. 1, and shown as a box in FIG. 3. Generally, the means for 
raising the stop 40 according to the present invention is only necessary 
when documents are being placed manually on the platen 10, and otherwise 
would probably interfere with the function of an automatic original 
document handler 30. Thus, the feature of raising the stop 40 when a 
document is detected on the platen 10 can be disabled when the document 
handler 30 is lowered to a usable position. This may be accomplished by 
any means known in the art, such as, for example, having the pivoted 
document handler press down a switch when it is lowered into the usable 
position, or any other means for indicating the use of an automatic 
document handler. Of course, the feature of raising the stop 40 when a 
document is detected on platen 10 can also be activated or disabled by a 
switch on the machine itself accessible directly to the human user. 
Returning to FIG. 2, additional devices similar to 50, such as those 
indicated as 70 and 72, can also be used for other specific purposes which 
may assist in the placement of original documents on the platen 10. For 
example, it can be seen that device 70, which functions in the same manner 
as device 50, is disposed along the same edge of the platen 10 as the 
stops 40. Device 70 is placed in such a position that an original document 
smaller than a given size would not be detected by the device, while an 
original document larger than a certain size would be detected by the 
device. One commonly-useful layout would be, for example, to place the 
device 70 twelve inches from the reference corner K, so that the device 70 
is capable of detecting legal-size (8.5".times.14") paper but would not 
detect letter-size (8.5".times.11") paper. Thus, if legal-size paper is 
detected by device 70, the machine could be automatically activated to 
select legal-size copy paper from a tray such as 20 or 22 as shown in FIG. 
1. 
Similarly, a device such as 72, disposed at a preselected distance from 
reference corner K as shown, could detect the presence of documents of a 
sufficient size relative to the distance between reference corner K and 
one or both of the devices 50 and 72. If an original document is placed on 
the platen 10, and the document is detected at device 50 but not device 
72, then the system may recognize that a document is of a certain small 
size (i.e., large enough to be detected by device 50, but not extending to 
device 72) and that the user may desire the option of magnifying the small 
document. 
FIG. 4 is a simplified systems diagram showing an extended version of the 
control system of the present invention. Once again, as in FIG. 3, the 
control system is generally indicated as 60; the boxes given reference 
numerals are intended to represent the physical elements, such as 
detectors, rollers, etc., disclosed in FIGS. 1-3. In FIG. 4 it can be seen 
that the inputs to control system 60 include detectors 50, 70, and 72, 
which are adapted to indicate the presence of a document at various 
locations along the edges of the platen 10. Among the outputs of control 
system 60 are the motors associated with rollers such as 21 and 23 shown 
in FIG. 1. As mentioned above, activation of one or the other of these 
rollers 21, 23 will relate to the selection of one or another size of copy 
sheet such as legal or letter size. It will be apparent that if the 
detector 70 as shown in FIG. 2 is used to detect an extra-long document, 
the presence of a document detected by device 70 would cause control 
system 60 to select the motor for roller 21 or 23 associated with 
legal-size paper so that the recorded image will fit onto the copy sheet. 
Similarly, control means 60 can be used to activate the 
focus/magnification device 16, as shown in FIG. 1, such as when device 50 
detects the presence of a document while device 72 does not; in such a 
case, what may be present on the platen 10 is a document of such a small 
size that magnification by magnification means 16 could be desired. Of 
course, it may be left to the user whether to activate a magnification 
device 16, and therefore control means 60 could also be operatively 
connected to a user interface generally indicated as 90, which may include 
a screen or other display device which displays to the human user a 
message such as "SMALL ORIGINAL DOCUMENT DETECTED--ADJUST MAGNIFICATION IF 
DESIRED". Also, control means 60 could be used to activate the 
electro-mechanical means 44 which extend the stop 40 to a functional 
position. Another conceivable function of control means 60 could be to 
provide for an automatic exposure of the document (i.e., in effect "push 
the button" of the copier) a fixed time after the document is detected on 
the platen, so that a large number of small documents may be copied 
rapidly. 
FIG. 5 is an example flowchart showing how a system using the present 
invention can be incorporated in a copier. As can be seen in FIG. 5, when 
the automatic document handler 30 is disabled and swung into the up 
position, the sensors such as 52 can detect the presence of a document on 
platen 10. When such a document is detected, stops 40 are raised. After 
some time is given for allowing the user to register the document against 
stops 40, the main drive of the copier, which initiates the entire copying 
process, is activated, in a manner familiar in the art. After the copy is 
made of the document on the platen, various timing devices can be employed 
to determine whether another document is to be manually placed on the 
platen 10. It may be desirable to leave the stops 40 up for a few seconds 
to give time to the user to place another original document on platen 10, 
as shown in the flowchart of FIG. 5. However, if the copier detects no 
activity after a predetermined number of seconds, a time-out procedure can 
be initiated with the stops 40 being retracted. Otherwise, if the lid of 
document handler 30 is put down, an interlock switch which detects the 
position of document handler 30 may be activated, to re-enable the 
document handler 30. The flowchart of FIG. 5 is given as an example only, 
and different system-wide procedures for using the system of the present 
invention are possible, depending on the specific application. 
While this invention has been described in conjunction with various 
embodiments, it is evident that many alternatives, modifications, and 
variations will be apparent to those skilled in the art. Accordingly, it 
is intended to embrace all such alternatives, modifications, and 
variations as fall within the spirit and broad scope of the appended 
claims.