Paper feed cassette

The invention provides a sheet feed cassette for holding various sizes of sheets to be fed to an image recording apparatus in a feed direction. The cassette comprises a first casing having a sheet placement area, and a second casing slidably connected to the first casing for expanding the area. The first casing is detachably mounted on the image recording apparatus.

BACKGROUND OF THE INVENTION 
The present invention relates to a paper feed cassette for sheets used in 
an image recording apparatus such as a copier, facsimile, printer, or the 
like. 
A plurality of papers used in the image recording apparatus is loaded in a 
paper feed cassette which is usually made to match a specific paper size. 
The paper feed cassette is mounted on the recording apparatus, and the 
paper is automatically pulled out sheet by sheet from the cassette by a 
paper feed means such as paper feed rollers and the like provided in the 
image recording apparatus. 
Generally, in a recording apparatus which can record on papers of different 
sizes, a plurality of paper feed cassettes, each being used for one paper 
size, is mounted on the side or the front of the apparatus main body so 
that papers can be fed selectively. However, the recording apparatus in 
which papers with multiple sizes are fed requires a plurality of paper 
feeds and, thus, the apparatus becomes complicated and its cost is 
increased. Furthermore, its overall height is increased, resulting in 
large size. 
In order to avoid these problems, there has been used a recording apparatus 
in which a universal paper feed cassette is detachably provided to a paper 
feed device in the apparatus main body. The universal paper feed cassette 
is a cassette in which a position regulation member can be set in various 
positions so that papers with different sizes can be loaded in the 
cassette. 
The above-described universal paper feed cassette has a casing which can 
accept the paper of the largest size, and it is provided with a position 
regulation member with which the papers with different sizes can be 
positioned, and therefore, the casing becomes large in size. For this 
reason, a portion of the paper feed cassette protrudes from the side or 
front of the main body of the recording apparatus when the universal paper 
feed cassette is mounted on the apparatus, resulting in the used for a 
large installation space and creating an obstruction in operation. 
Furthermore, when using small or medium-sized papers (for example, A4 
size, B5 size, or the like) which are frequently used in such apparatus, 
it is undesirable for the large-sized universal paper feed cassette to 
protrude from the apparatus. Especially, when the paper feed cassette 
protrudes to a great extent from the front of the apparatus, it causes not 
only the obstruction in the operation, but also the risk of damage to the 
cassette caused by an impact. When the paper feed cassette is covered by 
enlarged enclosures of the recording apparatus in order to reduce the 
amount of protrusion of the paper feed cassette, the recording apparatus 
has a disadvantage of a large size. 
SUMMARY OF THE INVENTION 
An object of the present invention is to solve the above-described problems 
of the conventional paper feed cassette, and to provide a paper feed 
cassette in which, when using the cassette for papers of frequently used 
sizes, the protrusion of the cassette from the front of the recording 
apparatus main body or from the side thereof is minimized and, when a 
large-sized paper is fed, the paper placement area can be easily enlarged 
so that the large-sized paper can be loaded. 
In order to accomplish the above-described objects a paper feed cassette of 
the present invention comprises: a first casing which has a paper 
placement area capable of holding the smallest-sized paper and a second 
casing which is movably connected to the first casing and is capable of 
holding the large sized paper by enlarging the paper placement area, in a 
universal type paper feed cassette which can hold papers of various sizes 
by regulating their positions and can be mounted on a paper feed device. 
In an embodiment of the paper feed cassette of the invention, the leading 
edge regulator, which regulates the downstream side of the paper, is 
provided on the first casing, and a trailing edge regulator which 
regulates the upstream side of the paper is provided on the second casing. 
Another embodiment of the cassette of the present invention comprises: a 
first casing which can hold at least the smallest-sized paper and can be 
mounted on the paper feed device; a second casing which is connected to 
the first casing and is movable in the direction of the paper feed, a 
first moving device for moving width regulation plates in the 
perpendicular direction to the paper feed direction and for arranging the 
paper width in the first casing; and a second moving device which moves 
the second casing; in the paper feed direction in cooperation with the 
first moving device in a universal type paper feed cassette which can 
contain papers of various sizes including a large size and a small size by 
regulating to be positioned, and can be mounted on a paper feed device. 
When either one of the width regulation plate or the second casing is 
moved over a predetermined length, the above-described first moving device 
and the second moving device are moved in cooperation with each other so 
that the second casing or the width regulation plate are moved over 
another predetermined length. 
In another embodiment of the paper feed cassette, the paper placement area 
formed between the first casing and second casing is determined so that 
when the width regulation plate is set for one dimension of a standard 
size paper, the second casing will be set for the other dimension of the 
paper. 
Further, the above-described paper feed cassette can further comprise a 
first moving device having a first rack gear and a first pinion gear 
engaging the first rack gear, a second moving device having a second rack 
gear and a second pinion gear engaging the second rack gear. The first and 
the second pinion gears have a common axis of rotation, and their gear 
ratio is determined based on the desired relative movement of the width 
regulation plates and the second casing. 
Furthermore, the paper feed cassette of the present invention can comprise 
a paper size indicator on the side walls of the first casing or the second 
casing; and a detector can be provided in the paper feed device in the 
apparatus thereby the movement of the indicator based on the movement of 
the second casing is detected by the detector so that the size of paper 
loaded in the cassette can be determined.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 9 shows the main sectional view from the left side of a color printer 
on which the paper feed cassette of the present invention can be mounted. 
FIG. 10 shows a corresponding perspective view. Apparatus main body 10 is 
enclosed by operation panel 11 on its front surface, upper cover (an upper 
lid member) 12, which can be opened and closed, toner supply cover 13, 
front cover 14, and the like. Detachable process cartridge 15 and paper 
feed cassette 16 are provided on the apparatus main body. 
Process cartridge 15 comprises photoreceptor belt 17, developing units 23, 
charger 21, cleaning unit 25. Photoreceptor belt 17, which is an image 
carrier, is coated with a photosensitive layer such as an organic 
photoconductor layer (OPC) on its surface and Belt 17 is stretched between 
driving roller 18 and driven roller 19 for clockwise rotation. A charging 
means, an exposure means, a developing means, a transfer means, and a 
cleaning means are provided around photoreceptor belt 17. Charging means 
21 can be a conventional charger such as a corona charger, or a Scorotron 
charger. 
The developing means comprises a plurality of developing units 23a, 23b, 
23c and 23d in which toners (developing agents) of different colors such 
as yellow, magenta, cyan, and black are contained respectively. These 
developing units 23a-23d develop the latent image on photoreceptor belt 17 
and form a visible toner image by, in this case, the non-contact 
development. 
The cleaning blade of cleaning means 25 is kept apart from the surface of 
photoreceptor belt 17 during the image forming process, and closely 
contacts the surface of photoreceptor belt 17 with pressure to clean it 
only after transferring the toner image onto transfer material P. Toner 
collecting box 26 receives the residual toner on photoreceptor belt 17 
which is removed by cleaning means 25. 
In the present example, processing units forming the above-described image 
forming portion of a printer such as photoreceptor belt 17, charger 21, 
developing units 23a through 23d in which toner of each color is contained 
respectively, cleaning means 25, and toner collecting box 26 are 
integrated into process cartridge 15 as a unit, which can be detachably 
mounted on apparatus main body 10. When the process cartridge 15 is 
mounted on the main body to form images, the exposure means, transfer 
means and other elements are positioned around photoreceptor belt 17. 
The exposure means is semiconductor laser-writing optical system unit 
(hereinafter, called an optical system unit) 22, which exposes the surface 
of photoreceptor belt 17 charged by charger 21 and forms a latent image 
thereon. The transfer means transfers the toner image formed on 
photoreceptor belt 17 to transfer material P by transfer unit 24, which 
may be a transfer corona discharger. 
FIG. 1 and FIG. 2 show an embodiment cf the paper feed cassette of the 
present invention. FIG. 1(A) shows a plan view of a paper feed cassette 
which is adjusted to accept small papers, FIG. 1(B) shows its central 
sectional view, and FIG. 1(C) shows its side view. 
Paper feed cassette 16 of the present invention has a two-piece structure, 
and comprises first casing 161 having a paper placement area capable of 
holding the smallest-sized paper (for example, A4 sized-paper) and second 
casing 162 which can hold a large sized-paper (for example, A3 
sized-paper) by extending the paper placement area through slidable 
connection with first casing 161. Movable bottom plate 163 is slidably 
supported on the bottom portion of first casing 161. 
First casing 161 comprises a box, the upper surface and the right side of 
which are open; and has a lateral width W in terms of the inside 
dimensions is set slightly larger than the width of small sized-paper P2 
(for example, the width of A4 sized-paper, 297 mm) to be loaded therein. 
Length l in terms of the inside dimensions is slightly longer than the 
length of small sized-paper P2 (for example, the length of A4 sized-paper, 
210 mm) to be loaded therein. An inside wall facing toward the direction 
of the paper feed of first casing 161 has a leading edge regulator 161A 
against which the leading edge of the paper is aligned. An inside wall 
facing toward the upstream direction of the paper feed of second casing 
162 has trailing edge regulator 162A which contacts the trailing edge of 
the paper to align it. 
Small-sized paper P2 (for example, A4 sized-paper) can be loaded in the 
inside dimensions W and l of the paper feed cassette shown in FIG. 1 
wherein first casing 161 and second casing 162 are combined to form a 
closed casing. Paper feed cassette 16 thus structured is mounted on the 
paper feed portion of the image recording apparatus. 
FIG. 2(A) shows a plan view of the paper feed cassette such that large 
sized-paper can be loaded, FIG. 2(B) shows its central sectional view, and 
FIG. 2(C) shows its side view. Groove portions 161B formed on both sides 
of first casing 161, engage claw portions 162B of second casing 162 so 
that the claw portions may slide along the groove portions. When second 
casing 162 is pulled out until an end of upper groove portion 161B comes 
into contact with claw portion 162B and stops, the paper placement area is 
enlarged and formed into the shape shown in FIG. 2. Large-sized paper P1 
having the length L can be loaded therein. After replenishing or changing 
paper P2, the casing is mounted on the paper feed portion of the image 
recording apparatus. 
Expandable universal paper feed cassette 16 in which both of large 
sized-paper of A3 and small-sized paper of A4 which having the same width 
W and different lengths (L and l) can be loaded by regulating the 
positions of the leading edge and the trailing edge has been explained 
above. However, the present invention can also be applied to a universal 
paper feed cassette in which B4 and B5 sized-papers in JIS-B system can be 
loaded. The present invention can also be applied to a universal paper 
feed cassette in which papers of other standards such as letter size paper 
(8.5 inches .times.11 inches) and legal size paper (8.5 inches .times.14 
inches) in the U.S.A. paper size standards can be loaded. 
Referring to FIG. 1(C) and FIG. 2(C), indication plates for paper size 
indication (for example, reflecting plates) 164A and 164B are affixed on 
both sides of first casing 161. On the other hand, sensors for paper size 
detection (for example, reflection type photosensors) 165A, 165B are fixed 
on the cassette receive portion of the paper feed portion of the image 
recording apparatus. 
When paper feed cassette 16, which holds small-sized paper P2 shown in FIG. 
1(C) is mounted on the cassette receiving portion, size indicating plate 
164A, affixed to the second casing, is detected by second sensor 165A, and 
the presence of small-sized paper is detected thereby. The proper paper 
size (for example, A4) can be displayed on operation panel 11. At this 
time, size indicating plate 164B, on casing 161 is not detected because it 
is covered by the side wall of second casing 162. 
When the paper feed cassette shown in FIG. 2(C), which holds large-sized 
paper P1 shown in FIG. 2(C) is mounted on the cassette receiving portion, 
size detection plate 164B affixed to the first casing is detected by 
sensor 165B, and the presence of large-sized paper is detected thereby. 
The paper size (for example, A3) can be displayed on operation panel 11. 
In the same way as the foregoing, for a combination paper feed cassette for 
various sizes of papers, appropriate size indicating plates can also be 
provided, and the paper sizes can be identified and displayed by a 
plurality of sensors. For example, when four sensors are placed in 
parallel, 15 kinds of papers (2.sup.4 -1=15) can be identified. The 
detected paper size can be transmitted to the image recording apparatus 
for any other desired function. 
A universal paper feed cassette which is used for papers with the same 
width W (A3 and A4, B4 and B5, legal size and letter size, etc.) has been 
described above. However, the present invention can be applied also to a 
universal paper feed cassette which can hold papers having different 
widths W and lengths L. (FIG. 3) 
FIGS. 3, 4 and 5 are partially broken away plan views of another embodiment 
of the present invention. In FIG. 3, two long groove portions 161C and 
161D are perpendicular to the paper feed direction and are located on a 
paper placement area on the upper surface of first casing 161. Width 
regulation plate 166A standing vertically on the upper side of first 
casing 161, and rack gear 167A on the rear side are integrally fixed and 
sandwiching long groove portion 161C, so that they can move along the long 
groove portion 161C. In the same way, width regulation plate 166B and rack 
gear 167B can move along the other long groove portion 161D. 
Rack gears 167A and 167B mesh with rotatable pinion gear 169A which engages 
shaft 168 located on center line CL of the first casing. When either width 
regulation plate 166A or 166B is moved inwardly in a direction 
perpendicular to the paper feed direction the other width regulation 
plate, which is linked with the other regulation plate, is moved the same 
distance toward the center line CL. 
FIG. 4 and FIG. 5 show an embodiment having means for moving second casing 
162 based upon the length/width relationship of standard paper sizes; the 
movement of the second casing and the movement of the width regulation 
plates are inter connecting. In FIG. 4 and FIG. 5, pinion gear 169B having 
a larger pitch circle than pinion gear 169A is integral with and located 
on same axis 168 as pinion gear 169A, which moves the width regulation 
plate and can be rotated together with pinion gear 169A. Pinion gear 169B 
meshes with rack gear 170 which is fixed to the rear surface of second 
casing 162; pinion gear 169B and rack gear 170 forms the second moving 
device. Second casing 162 slides along a guide surface of the inner 
surface of first casing 161; thus, the paper placement area is expanded to 
accept larger papers. 
Thus the first moving means which can move in the direction perpendicular 
to that of paper feed, and the second moving means which can move in the 
direction of paper feed, are interconnected. When either of the width 
regulation plates 166A and 166B is moved the other width regulation plate 
moves the same distance synchronously and symmetrically; and further, 
second casing 162 moves relative to first casing 161 a distance 
corresponding to the width/length ratio of the desired standard size 
paper. Specifically, in the JIS-A and JIS-B systems the ratio of the 
length to width thereof is about .sqroot.2, therefore, the ratio of the 
number of teeth Z2 of pinion gear 169 B which moves second casing 162 to 
the number of teeth Z1 of pinion gear 169A which is rotated by movement of 
width regulation plates 166A and 166B, is 2.sqroot.2. 
By setting the gear ratio in this way, when width regulation plate 166A or 
166B is moved distance m in the direction perpendicular to the paper feed 
direction, second casing 162 moves a distance 2.sqroot.2 m. Accordingly, 
not only the width of paper P is regulated by the width regulation plates 
166A and 166B, but also and at the same time, the rear half portion of 
paper P is stably placed in second casing 162, so that paper P is 
positioned between leading edge regulator 161A and trailing edge regulator 
162A. 
In the above embodiments, the various size papers are placed on the center 
of lateral position and the left and right width regulation plates are 
moved symmetrically by the same distance. (See FIG. 6(A).) However, as 
shown in FIG. 6(B), when only one of the regulation plates is moved to one 
side of the paper, the gear ratio of pinion gears should be set to 
.sqroot.2. Also, as shown in FIG. 6(C), when the various size papers are 
placed longitudinally in the center thereof, the gear ratio of pinion 
gears should also be set to .sqroot.2. 
In the above-described embodiment, the movement of the width regulation 
plate and second casing is effected by meshing the rack gear with the 
pinion gear. However, the objects of the present invention can also be 
accomplished by a wire wound around a pulley; or a timing pulley combined 
with a timing belt; the ratio of diameters of the pulleys is 2.sqroot.2 or 
.sqroot.2, depending on the orientation of the paper in the cassette. 
Furthermore, instead of the manual operation, the pinion gears 169A and 
169B can be driven by a motor; in that case the width regulation plates 
and the movable second casing can be stopped by the motor-drive at a 
predetermined position determined by the size of recording papers. 
FIG. 7(A) is a plan view of paper feed cassette 16 which holds the 
largest-sized paper (A3 type of length L1). FIG. 7(B) is a central 
sectional view thereof. Second casing 162 is held by the first casing so 
that the second casing is pulled out to its maximum extension. 
FIG. 7(C) is a side view which shows an indicator which means indicates the 
condition of paper feed cassette 16. The loaded status of the A3-size 
paper in the cassette is detected by sensor 165B when the paper size 
detection plate 164B, glued on the outside surface of the first casing is 
detected by sensor 165B. 
When B4-size paper is in paper feed cassette 16, width regulation plates 
166A and 166B are moved to width W2 of the B4 paper and, at the same time, 
the second casing is moved to length L2 in the left direction. At this 
time, size detection plates 164B and 164C are detected by sensors 165B and 
165D. 
Similarly, when A4 paper is loaded, the width is set to W3 and the length 
is set to L3. At this time, size detection plates 164B, 164C, 164D, and 
164E are detected by sensors 165B, 165C, 165A and 165D. FIG. 8(A) is a 
plan view of paper feed cassette 16 wherein the smallest-sized paper (for 
example, B5 paper of width W4 and length L4) is loaded; FIG. 8(B) is its 
center section, and FIG. 8(C) is a side thereof. Reflecting plate 164B of 
first casing 161 is covered by second casing 162, size detection plates 
164D and 164E thereof are detected by sensors 165B and 165C, and the 
loaded paper size is recognized and can be displayed. 
In the above-described embodiments, the long side of the paper has been 
placed in the paper feed direction. However, cassette of the present 
invention is equally operable if the short side of the paper is placed in 
the paper feed direction. Of course, appropriate adjustments of the rack 
and pinion gear ratio must be made. 
In this way, the placement, in a lateral or longitudinal position, of 
papers ranging from the maximum-size A3 to the minimum-size, B5, as well 
as U.S.A. standard-size papers or the like, can be accomodated by 
enlargement and contraction of the casings and, can be easily determined 
by the indicators. 
An example of the indicators is shown in Table 1. 
(TABLE 1) 
______________________________________ 
Size detection plate 164 
No. Paper size A B C D 
______________________________________ 
1 B4 .largecircle. 
.largecircle. 
.largecircle. 
.largecircle. 
2 B5R .largecircle. 
.largecircle. 
.largecircle. 
3 B5 .largecircle. 
.largecircle. 
.largecircle. 
4 B6 .largecircle. 
.largecircle. 
5 A3 .largecircle. .largecircle. 
.largecircle. 
6 A4R .largecircle. .largecircle. 
7 A4 .largecircle. .largecircle. 
8 Post card .largecircle. 
9 8.5" .times. 14" .largecircle. 
.largecircle. 
.largecircle. 
10 F4 .largecircle. 
.largecircle. 
11 .largecircle. 
.largecircle. 
12 5.5" .times. 11R" .largecircle. 
13 11" .times. 17" .largecircle. 
.largecircle. 
14 8.5" .times. 11R" .largecircle. 
15 8.5" .times. 11" .largecircle. 
______________________________________ 
Since the universal paper feed cassette according to the present invention 
can enlarge and contract to accept various paper sizes, when the cassette 
is mounted on the main body of the image recording apparatus, the amount 
of protrusion from the front or the side of the apparatus is at a minimum. 
Thus, the installation area can be minimized, and impact and damage due to 
the cassette protrusion rarely occurs. 
Furthermore, the paper feed cassette according to the present invention can 
position the trailing edge of the paper concurrently with the width 
arrangement of the paper since the movable second casing moves forward and 
backward, being linked with the movement of the paper width regulation 
plate. Or, the cassette can easily be set to a predetermined paper width 
by operating the movable second casing since they are linked. 
Since the paper placement area determined by the width and length of the 
paper can be set automatically by either of the movement of the paper 
width regulation plates or of the second casing, two motions can be 
accomplished at the same time by a single operation. Thus, operability is 
improved, and problems such as defective paper arrangement have been 
minimized. 
Moreover, since various sizes of papers loaded in the universal paper feed 
cassette can easily be detected by the enlargement and contraction of the 
cassette casings at the time of mounting the paper feed unit, wasteful 
recording due to the failure of selection of the proper paper size can 
also be minimized.