Information
-
Patent Grant
-
6357848
-
Patent Number
6,357,848
-
Date Filed
Wednesday, December 22, 199924 years ago
-
Date Issued
Tuesday, March 19, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 347 16
- 347 101
- 347 104
- 347 19
- 400 630
- 400 632
- 400 579
- 271 26501
- 346 134
- 358 112
-
International Classifications
-
Abstract
An apparatus and method for reducing print media edge margin tolerances in a printing device with one or more supplies of print media are disclosed. An apparatus embodiment includes a sensor that detects a supply of print media and outputs a signal indicative of the detected supply of print media. The apparatus also includes a computing device that receives the signal indicative of the detected supply of print media. The computing device determines a median position of the supply of print media in a printzone of the printing device based on a plurality of trials of feeding the supply of print media into the printzone and adjusts a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone. A method embodiment includes determining a range of positions of a supply of print media in a printzone of a printing device and determining a median position of the supply of print media in the printzone. The method additionally includes adjusting a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone. Further characteristics and features of the apparatus and method are disclosed herein, as are exemplary alternative embodiments.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to printing devices. More particularly, the present invention relates to an apparatus and method for reducing print media edge margin tolerances in a printing device with one or more supplies of print media.
Printing devices, such as inkjet printers and laser printers, use printing composition (e.g., ink or toner) to print text, graphics, images, etc. onto a print medium in a printzone of the printing device. Inkjet printers may use print cartridges, also known as “pens”, which shoot drops of printing composition, referred to generally herein as “ink”, onto a print medium such as paper, transparencies or cloth. Each pen has a printhead that includes a plurality of nozzles. Each nozzle has an orifice through which the drops are fired. To print an image, the printhead is propelled back and forth across the page by, for example, a carriage while shooting drops of ink in a desired pattern as the printhead moves. The particular ink ejection mechanism within the printhead may take on a variety of different forms known to those skilled in the art, such as thermal printhead technology.
In a current thermal system, a barrier layer containing ink channels and vaporization chambers is located between an orifice plate and a substrate layer. This substrate layer typically contains linear arrays of heating elements, such as resistors, which are energized to heat ink within the vaporization chambers. Upon heating, the ink in the vaporization chamber turns into a gaseous state and forces or ejects an ink drop from an orifice associated with the energized resistor. By selectively energizing the resistors as the printhead moves across the print medium, the ink is expelled in a pattern onto the print medium to form a desired image (e.g. picture, chart and/or text).
Printing devices typically include one or more print media input devices, such as print media input trays for sheets of print media or input racks for rolls of print media. These input devices feed a supply of print media into the printzone of the printing device where printing composition is deposited on the print media to form the desired image.
Ideally, the print media is fed into the printzone each time at the same location to help assure that the image is exactly placed on the print media. However, due to design and manufacturing tolerances, such exact positioning is not possible. Instead, the supply of print media is actually positioned in a range of distances around the ideal or desired location. If this range is wide enough, then the output print quality of images from a printing device suffers. In certain instances, the output print quality may be illegible and require a new print job to be run which is wasteful and time consuming, particularly for large print jobs or print jobs that are left to run unattended, such as those that are done overnight. As a consequence, printing device throughput is also reduced. Also, usable print area may be wasted depending on where the print media is actually placed in the printzone. These problems are only exacerbated as the number of print media input devices increases because each input device has a different range of distances around the ideal or desired location, which range of distances tends to increase as an input device is positioned further from the printzone.
One way in which to help alleviate these problems is to attempt to minimize design and manufacturing tolerances which should reduce the range of distances around the ideal or desired location. This approach, however, is not without its own problems including increased complexity of both design and manufacture, as well as increased cost for such a print media input device. Again these problems are only exacerbated as the number of input devices increases.
Another approach to help alleviate these problems is to sense the edge of a print medium each time the print medium is feed into a printzone and adjust the position of where printing begins based on where the edge is located in the printzone. Such an approach, while greatly increasing image placement accuracy on a print medium and, therefore, printing device output print quality, has the drawback of decreasing printing device throughput because of the time required to sense the edge of the print medium in the printzone each time a new print medium enters the printzone, and adjust image placement accordingly.
A further approach to help alleviate these problems is to use print media registration devices that position print media correctly in the printzone. This approach, as with those that attempt to minimize design and manufacturing tolerances, is not without its own problems including increased complexity of both design and manufacture, as well as increased cost for such a print media input device. As discussed above, such problems are only exacerbated as the number of input devices increases.
Alleviation of these problems would be a welcome improvement, thereby helping minimize delay in the completion of printing tasks, helping maximize printing device throughput, and helping prevent instances of waste of print media. Accordingly, the present invention is directed to solving those problems caused by positioning of print media in a range of distances around an ideal or desired location in the printzone of a printing device. The present invention accomplishes this objective by providing an apparatus and method for reducing edge margin tolerances in a printing device with one or more supplies of print media while at the same time attempting to minimize the impact on printing device throughput.
An embodiment of a method in accordance with the present invention for use in a printing device, the printing device having a supply of print media and being configured to feed the supply of print media into a printzone where printing composition is deposited on the supply of print media, includes determining a range of positions of the supply of print media in the printzone. The method additionally includes determining a median position of the supply of print media in the printzone and adjusting a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
In the above-described embodiment of a method in accordance with the present invention, the range of positions of an edge of the supply of print media may be determined, as can the median position of the edge of the supply of print media in the printzone. Based on the determined median position of the edge of the supply of print media in the printzone, the position in the printzone for the supply of printing media where printing composition is deposited may be adjusted.
The above-described embodiments of a method in accordance with the present invention may be modified to work with any number of additional supplies of print media where the printing device is configured to selectively feed any one of the supplies of print media into the printzone where printing composition is deposited on the selected supply of print media. Additionally, the supply or supplies of print media may comprise at least one sheet of print media in a print media input tray.
An embodiment of an apparatus in accordance with the present invention for use in a printing device, the printing device having a supply of print media and being configured to feed the supply of print media into a printzone where printing composition is deposited on the supply of print media, includes a sensor configured to detect the supply of print media and output a signal indicative of the detected supply of print media. The apparatus also includes a computing device coupled to the sensor to receive the signal indicative of the detected supply of print media. The computing device is configured to determine a median position of the supply of print media in the printzone based on a plurality of trials of feeding the supply of print media into the printzone. The computing device is further configured to adjust a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
In the above-described embodiment of a apparatus in accordance with the present invention, the sensor may be configured to detect an edge of the supply of print media and output a signal indicative of the detected edge of the supply of print media. In such cases, the computing device is configured to determine a median position of the edge of the supply of print media in the printzone based on a plurality of trials of feeding the supply of print media into the printzone and to adjust a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the edge of the supply of print media in the printzone.
The above-described embodiments of an apparatus in accordance with the present invention may be modified to work with any number of additional supplies of print media where the printing device is configured to selectively feed any one of the supplies of print media into the printzone where printing composition is deposited on the selected supply of print media. Additionally, the supply or supplies of print media may comprise at least one sheet of print media in a print media input tray.
An alternative embodiment of an apparatus in accordance with the present invention for use in a printing device, the printing device having a supply of print media and being configured to feed the supply of print media into a printzone where printing composition is deposited on the supply of print media, includes structure for determining a range of positions of the supply of print media in the printzone. The apparatus also includes structure for determining a median position of the supply of print media in the printzone and structure for adjusting a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
In the above-described alternative embodiment of an apparatus in accordance with the present invention, the structure for determining a range of positions may determine the range of positions of an edge of the supply of print media in the printzone and the structure for determining a median position may determine the median position of the edge of the supply of print media in the printzone. In such cases, the structure for adjusting a position in the printzone may adjust the position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the edge of the supply of print media in the printzone.
The above-described alternative embodiments of an apparatus in accordance with the present invention may be modified to work with any number of additional supplies of print media where the printing device is configured to selectively feed any one of the supplies of print media into the printzone where printing composition is deposited on the selected supply of print media. Additionally, the supply or supplies of print media may comprise at least one sheet of print media in a print media input tray.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of a printing device that includes an embodiment of the present invention.
FIG. 2
is a diagrammatic view of an alternative embodiment of a printing device that includes an embodiment of the present invention.
FIG. 3
is a side view of a print medium edge sensor in accordance with the present invention configured to detect an edge of a print medium.
FIG. 4
is a diagram illustrating ranges of positions of edges of supplies of print media in a printzone of the printing device shown in
FIG. 2
, and also an ideal edge location for a sheet of print media in the printzone of the printing device shown in FIG.
2
.
FIG. 5
is a graph of probability distributions of determined ranges of edges of supplies of print media in the printzone of the printing device shown in
FIG. 2
for each feeder of the printing device.
FIG. 6
is a graph of probability distributions of the ranges of edges of supplies of print media in the printzone for each feeder of the printing device shown in
FIG. 2
after adjustment of where printing occurs in the printzone for each feeder in accordance with the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1
illustrates an embodiment of an inkjet printing device, sometimes referred to simply as a “printer,”
20
, here shown as an [a] “off-axis” inkjet printer, that includes an embodiment of the present invention and which may be used for printing business reports, correspondence, desktop publishing, and the like, in a industrial, office, home or other environment. A variety of inkjet printing devices are commercially available. For instance, some of the printing devices that may embody the present invention include plotters, portable printing units, copiers, cameras, video printers, and facsimile machines, to name a few, as well as various combination devices, such as combination facsimiles and printers. In addition, the present invention may be used in other types of printing devices such as “on-axis” inkjet printers, dot matrix printers, copiers, fax machines, and laser [jet] printers. For convenience, the concepts of the present invention are illustrated in the environment of inkjet printer
20
and an analogous generic printing device
100
, which is discussed more fully below in connection with FIG.
2
.
While printing device components may vary from model to model, a typical inkjet printer
20
includes a frame or chassis
22
surrounded by a housing, casing or enclosure
24
, typically made of a plastic material. Sheets of print media are fed through a printzone
25
by a print media handling system
26
. The print media may be any type of suitable material, such as paper, card-stock, transparencies, photographic paper, fabric, metalized media, etc. Print media handling system
26
includes a print media input tray
28
for storing sheets of print media for printing. A series of conventional print media drive rollers
30
rotate about on shaft
31
which is driven by a motor
35
through a series of drive gears
33
and
34
. Gears
33
and
34
are rotateably coupled to shaft
31
to rotate shaft
31
in a direction generally indicated by arrow
93
. Drive rollers
30
are used to move print media from input tray
28
, through printzone
25
and, after printing, onto a pair of extendable output drying wing members
36
, shown in a retracted or rest position in FIG.
1
. Wings
36
momentarily hold a newly printed sheet of print media above any previously printed sheets still drying in an output tray
37
. Print media handling system
26
also includes means for accommodating different sizes of print media, including letter, legal, A-4, B, envelopes, etc. This means includes a print medium length adjuster
38
and a print medium width adjuster
39
. Print medium length adjuster
38
and print medium width adjuster
39
are manually repositionable against the sides of different sizes of print medium, and thereby accommodate for these different sizes. An envelope feed port
29
may be used in lieu of repositioning print medium length adjuster
38
and print medium width adjuster
39
to accommodate for the smaller size of such envelopes.
As shown in
FIG. 1
, print media handling system
26
also includes an additional print media input tray
41
. For storing sheets of print media for printing. Drive rollers
30
are also used to move print media from input tray
41
, through printzone
25
and, after printing, onto extendable output drying wing members
36
, as discussed above. Although not shown in
FIG. 1
, it is to be understood that print media input tray
41
may also include means for accommodating different sizes of print media, including letter, legal, A-4, B, envelopes, etc., such as print medium length adjuster
38
and a print medium width adjuster
39
.
The present invention may be used with printing devices that include any number of additional print media input trays for sheets of print media and/or print media racks for rolls of print media. Additionally, the present invention may be used with printing devices that include only one print media input tray for sheets of print media or only one print media rack for rolls of print media. Further, print media handling system
26
and printing device
20
may be configured to support specific print tasks such as duplex printing (i.e., printing on both sides of the sheet of print media) and banner printing.
Printing device
20
also has a computing device
40
, illustrated as a microprocessor or controller, that receives instructions from a host device, typically a computer, such as a personal computer (not shown). Many of the functions of computing device
40
may be performed by a host computer, including any printing device drivers resident on the host computer, by electronics in the printing device, or by interactions between the host computer and the electronics. As used herein, the term “computing device
40
” encompass these functions, whether performed by a host computer, printing device
20
, an intermediary device between the host computer and printing device
20
, or by combined interaction of such elements. Computing device
40
may also operate in response to user inputs provided through a keypad
42
located on the exterior of casing
24
. A monitor (not shown) coupled to the computer host may be used to display visual information to a user of printing device
20
, such as the printer status or a particular program being run on the host computer. Personal computers, input devices, such as a keyboard and/or a mouse device, and monitors are all known to those skilled the art.
A carriage guide rod
44
is supported by chassis
22
to slideably support an off-axis inkjet carriage
45
for travel back and forth across printzone
25
along a scanning axis generally designated by arrow
46
in FIG.
1
. As can be seen in
FIG. 1
, scanning axis
46
is substantially parallel to be X-axis of the XYZ coordinate system shown in FIG.
1
. It should be noted that the use of the word “substantially” in this document is used to account for things such as engineering and manufacturing tolerances, as well as variations not affecting performance of the present invention. Carriage
45
is also propelled along guide rod
44
into a servicing region, generally indicated by arrow
48
, located within the interior of housing
24
of printing device
20
. A conventional carriage drive gear and motor assembly (both of which are not shown in
FIG. 1
) may be coupled to drive an endless loop, which may be secured in a conventional manner to carriage
45
, with the motor operating in response to control signals received from a computing device
40
to incrementally advanced carriage
45
along guide rod
44
in response to movement of the motor.
In printzone
25
, a sheet of print medium receives ink from an inkjet cartridge, such as black ink cartridge
50
and three monochrome color ink cartridges
52
,
54
, and
56
. Cartridges
50
,
52
,
54
, and
56
are also called “pens” by those skill the art. Pens
50
,
52
,
54
, and
56
each include small reservoirs for storing a supply of printing composition, referred to generally herein as “ink” in what is known as an “off-axis” ink delivery system, which is in contrast to a replaceable ink cartridge system where each pen has a reservoir that carries the entire ink supply as the printhead reciprocates over printzone
25
along carriage scan axis
46
. The replaceable ink cartridge system may be considered an “on-axis” system, whereas systems which store the main ink supply at a stationary location remote from the printzone scanning axis are called “off-axis” systems. It should be noted that the present invention is operable in both off-axis and on-axis systems, as well as non-inkjet systems such as dot matrix and laser jet systems.
In the illustrated off-axis printing device
20
, ink of each color from each printhead is delivered via a conduit or tubing system
58
from a group of main ink reservoirs
60
,
62
,
64
, and
66
to the on-board reservoirs of respective pens
50
,
52
,
54
, and
56
. Ink reservoirs
60
,
62
,
64
, and
66
are replaceable ink supplies stored in a receptacle
68
supported by printer chassis
22
. Each of pens
50
,
52
,
54
, and
56
has a respective printhead, as generally indicated by arrows
70
,
72
,
74
, and
76
, which selectively ejects ink to form an image on a print medium in printzone
25
.
Printheads
70
,
72
,
74
, and
76
each have an orifice plate with a plurality of nozzles formed therethrough in a manner well-known to those skill the art. The illustrated printheads
70
,
72
,
74
, and
76
are thermal inkjet printheads, although other types of printheads may be used, such as piezoelectric printheads. Thermal printheads
70
,
72
,
74
, and
76
typically include a plurality of resistors which are associated with the nozzles. Upon energizing a selected resistor, a bubble of gas is formed which ejects a droplet of ink from the nozzle onto the print medium in printzone
25
under the nozzle. The printhead resistors are selectively energized in response to firing command control signals delivered by a multi-conductor strip
78
(a portion of which is shown in
FIG. 1
) from computing device
40
to printhead carriage
45
.
An optical quadrature encoder strip
80
extends along the length of printzone
25
and over the area of service station region
48
to provide carriage
45
positional feedback information to computing device
40
, with a carriage position quadrature encoder reader (not shown in
FIG. 1
) being mounted on a back surface of printhead carriage
45
to read positional information provided by optical quadrature encoder strip
80
. Together, optical quadrature encoder strip
80
and carriage position quadrature encoder reader constitute a printing device carriage position quadrature encoder. Printing device
20
uses optical quadrature encoder strip
80
and the carriage position quadrature encoder reader to trigger the firing of printheads
70
,
72
,
74
, and
76
and to provide feedback for position and velocity of carriage
45
.
Optical encoder strip
80
may be made from things such as photo imaged MYLAR brand film, and works with a light source and a light detector (both of which are not shown in
FIG. 1
) of carriage position quadrature encoder reader. The light source directs light through strip
80
which is received by the light detector and converted into an electrical signal which is used by computing device
40
of printing device
20
to control firing of printheads
70
,
72
,
74
, and
76
and to control carriage
45
position and velocity. Markings or indicia on encoder strip
80
periodically block this light from the light detector of carriage position quadrature encoder reader in a predetermined manner which results in a corresponding change in the electrical signal from the detector of carriage position quadrature encoder reader which is processed by computing device
40
.
A print medium axis position quadrature encoder
84
is also shown in FIG.
1
. Print medium axis position quadrature encoder
84
provides positional feedback information to computing device
40
regarding the position of print media drive rollers
30
. Printing device
20
uses print medium axis position quadrature encoder
84
in combination with flag
86
to help accurately position print medium in printzone
25
and to control printing by one or more of printheads
70
,
72
,
74
, and
76
. Flag
86
detects the presence of print medium in printzone
25
. Print medium axis position quadrature encoder
84
includes a rotary encoder
88
and a pair of rotary encoder readers
90
and
92
. Rotary encoder
88
is coupled to shaft
31
to rotate therewith in the direction generally indicated by arrow
93
.
Rotary encoder
88
may be made from things such as photo imaged MYLAR brand film, and works with a light source and a light detector (both of which are not shown) of each of rotary encoder readers
90
and
92
. These light sources direct light through rotary encoder
88
which is received by the light detectors and converted into an electrical signal which is used by computing device
40
of printing device
20
to help accurately position print medium in printzone
25
and to control firing of printheads
70
,
72
,
74
, and
76
. Markings or indicia on rotary encoder
88
periodically block this light from the light detectors of rotary encoder readers
90
and
92
in a predetermined manner which results in a corresponding change in the electrical signal from the detectors of rotary encoder readers
90
and
92
which is processed by computing device
40
.
A schematic view of an alternative embodiment of a printing device
100
that also includes an embodiment of the present invention is shown in FIG.
2
. Some of the major elements of printing device
100
are shown in
FIG. 2
, including print engine
102
, print media handling system
104
, vacuum plenum
105
, and housing or casing
106
.
Print engine
102
may comprise any type of apparatus by which an image is recorded on a print medium, including inkjet printing mechanisms like those discussed above in connection with FIG.
1
and laser jet printing mechanisms. A computing device (not shown) like, for example, computing device
40
is used to control formation of images on print media by print engine
102
.
Print media handling system
104
includes a belt or web transport
108
that is disposed around a pair of driven rollers
110
and
112
. Rollers
110
and
112
may be selectively driven by the computing device (not shown) of printing device
100
and one or more motors and drive gears (both of which are not shown) so as to rotate about points
114
and
116
in either a clockwise or counter-clockwise direction which allows belt transport
108
to selectively move in either of the directions indicated by arrows
118
and
120
. Belt transport
108
is in fluid communication with vacuum plenum
105
by, for example, a plurality of apertures (not shown) formed though belt transport
108
. In this manner, print medium is held down on belt transport
108
for the span of the length of vacuum plenum
105
and can be moved to and from printzone
129
any number of times. This span may be changed by resizing the dimensions of vacuum plenum.
As can also be seen in
FIG. 2
, print media handing system
104
also includes a plurality of print media feeders
122
,
124
,
126
, and
128
. Feeders
122
,
124
,
126
, and
128
each include a tray for sheets of print media or a rack for a roll of print media, as well as the necessary components to transport print media to printzone
129
of printing device
100
for printing by print engine
102
via feed paths
130
,
132
,
134
, and
136
. Feeders
122
,
124
,
126
, and
128
may each be separately configured to hold various sized print media or fixed sized print media. The computing device (not shown) of printing device
100
is also coupled to each of feeders
122
,
124
,
126
, and
128
to control selective transport of print media from any one of feeders
122
,
124
,
126
, and
128
to printzone
129
for printing of images by print engine
102
.
As discussed above, the present invention may be used with printing devices having any number of print media input trays and/or racks which is noted in FIG.
2
through the use of the designation “Feeder n” for feeder
128
. Also, although not shown in
FIG. 2
, it is to be understood that printing device
100
includes many of the same components of printing device
20
which may be necessary for operation, such as one or more print media output trays or racks, a user interface, and one or more position encoders.
A side view of a print medium edge sensor
138
constructed in accordance with the present invention is shown in FIG.
3
. Print medium edge sensor
138
is configured to detect an edge of a print medium transported by either print media handling system
26
or print media handling system
104
to respective printzone
25
or printzone
129
, such as print medium
140
. Although some of the components of the print engine of printing device
20
are illustrated in
FIG. 3
, it is to be understood that print medium edge sensor
138
of the present invention may also be used with print engine
102
of printing device
100
, as well as with print engines of other printing devices.
As can be seen in
FIG. 3
, an embodiment of print medium edge sensor
138
includes optical quadrature encoder strip
80
, carriage position quadrature encoder reader
82
, and a print medium edge detector
142
.
In operation, print medium
140
is transported from either input tray
28
or input tray
41
to printzone
25
by print media handling system
26
. Upon entering printzone
25
, carriage
45
is moved in the direction of arrow
144
so that edge
146
of print medium
140
is detected by beam
148
of print medium edge detector
142
. Upon detection of edge
146
, the position on optical quadrature encoder strip
80
is recorded. A signal from sensor
138
is sent to computing device
40
indicating the position on optical quadrature encoder strip
80
at which edge
146
of print medium
140
was detected.
Ideally, the print media is fed into printzone
25
or
129
each time at the same location to help assure that the image is exactly placed on the print media. However, due to design and manufacturing tolerances, such exact positioning is not possible. Instead, the supply of print media is actually positioned in a range of distances around the ideal or desired location. If this range is wide enough, then the output print quality of images from a printing device
20
or
100
suffers. In certain instances, the output print quality may be illegible and require a new print job to be run which is wasteful and time consuming, particularly for large print jobs or print jobs that are left to run unattended, such as those that are done overnight. As a consequence, printing device
20
or
100
throughput is also reduced. Also, usable print area may be wasted depending on where the print media is actually placed in printzone
25
or
129
. These problems are only exacerbated as the number of print media input devices increases because each input device has a different range of distances around the ideal or desired location, which range of distances tends to increase as an input device is positioned further from printzone
25
or
129
.
One way in which to help alleviate these problems is to attempt to minimize design and manufacturing tolerances which should reduce the range of distances around the ideal or desired location. This approach, however, is not without its own problems including increased complexity of both design and manufacture, as well as increased cost for such a print media input device. Again these problems are only exacerbated as the number of input devices increases.
Another approach to help alleviate these problems is to sense the edge of a print medium each time the print medium is feed into printzone
129
and adjust the position of where printing begins based on where the edge is located in printzone
25
or
129
. Such an approach, while greatly increasing image placement accuracy on the print medium and, therefore, printing device
20
or
100
output print quality, has the drawback of decreasing printing device
100
throughput because of the time required to sense the edge of the print medium in printzone
25
or
129
each time a new print medium enters printzone
25
or
129
, and adjust the image placement accordingly.
A further approach to help alleviate these problems is to use print media registration devices that position print media correctly in printzone
25
or
129
. This approach, as with those that attempt to minimize design and manufacturing tolerances, is not without its own problems including increased complexity of both design and manufacture, as well as increased cost for such a print media input device. As discussed above, such problems are only exacerbated as the number of input devices increases.
Alleviation of these problems would be a welcome improvement, thereby helping minimize delay in the completion of printing tasks, helping maximize printing device throughput, and helping prevent instances of waste of print media. Accordingly, the present invention is directed to solving those problems caused by positioning of print media in a range of distances around an ideal or desired location in the printzone of a printing device. The present invention accomplishes this objective by providing an apparatus and method for reducing edge margin tolerances in a printing device with one or more supplies of print media while at the same time attempting to minimize the impact on printing device throughput.
Referring again to
FIG. 3
, in accordance with the present invention, computing device
40
of printing device
20
actuates print media handling system
26
to transport print media from print media input tray
28
to printzone
25
and also from print media input tray
41
to printzone
25
multiple times for each print media input tray to determine the range of positions of edge
146
of print media
140
in printzone
25
for print media input tray
28
and also for print media input tray
41
. Similarly, in accordance with the present invention, the computing device (not shown) of printing device
100
actuates print media handling system
104
to transport print media from print media feeders
122
,
124
,
126
, and
128
to printzone
129
multiple times for each print media feeder
122
,
124
,
126
, and
128
to determine the range of positions of the edge of print media in printzone
129
for print media feeders
122
,
124
,
126
, and
128
. Edge sensing by print medium edge detector
142
is dispensed with subsequent to the determination of such range of positions. As discussed above, the lack of the requirement to sense the edge of a print medium each time the print medium is feed into a printzone and adjust the position of where image printing begins based on that detected edge increases throughput of the printing device.
A diagram illustrating determined ranges of positions of edges of supplies of print media
154
,
156
,
158
, and
160
from respective feeders
122
,
124
,
126
, and
128
in printzone
129
of the printing device
100
is shown in FIG.
4
. Ranges
154
,
156
,
158
, and
160
are determined by the computing device (not shown) of printing device
100
from signals received from print medium edge sensor
138
. Also shown in
FIG. 4
is an ideal edge location
150
for sheets of print media like sheet of print media
152
in printzone
129
of printing device
100
. Although not shown, it is to be understood that a diagram for print media input trays
29
and
41
of printing device
20
would have distributions similar to those shown in FIG.
4
.
As can be seen in
FIG. 4
, each of the determined ranges of positions
154
,
156
,
158
, and
160
has a generally Gaussian or normal probability distribution. As can also be seen in
FIG. 4
, the edge margin error for all of feeders
122
,
124
,
126
, and
128
taken together extends over a range of sheet of print media
152
defined by lines
170
and
172
, and arrow
174
.
A graph
170
of these probability distributions of the determined ranges of positions
154
,
156
,
158
, and
160
is shown in FIG.
5
. In accordance with the present invention, the computing device (not shown) of printing device
100
is configured to determine the median positions
162
,
164
,
166
, and
168
of each of the edges of the supplies of print media from each of respective feeders
122
,
124
,
126
, and
128
in printzone
129
. These edges are those that correspond to edge
150
of sheet of print media
152
which are detected by a print medium edge sensor like print medium edge sensor
138
, as discussed above in connection with FIG.
3
. Median position
162
represents the most frequent location of an edge of a print medium from feeder
122
in printzone
129
. Median position
164
represents the most frequent location of an edge of a print medium from feeder
124
in printzone
129
. Median position
166
represents the most frequent location of an edge of a print medium from feeder
126
in printzone
129
. Median position
168
represents the most frequent location of an edge of a print medium from feeder
128
in printzone
129
.
Also in accordance with the present invention, the computing device (not shown) of printing device
100
adjusts the position in printzone
129
for each of the supplies of print media from feeders
122
,
124
,
126
, and
128
where printing composition is deposited based on the determined median position of the edge of the supply of print media in printzone
129
. For example, for print media from feeder
122
(Feeder
1
), the computing device (not shown) of printing device
100
is configured to adjust or shift the edge of the image to be printed by print engine
102
in printzone
129
fourteen (14) units on x-axis
172
to the left of y-axis
174
, where y-axis
174
represents the ideal location of any edge of print media in printzone
129
of printing device
100
. For print media from feeder
126
(Feeder
3
), the computing device of printing device
100
is configured to adjust or shift the edge of the image to be printed by print engine
102
in printzone
129
to a lesser degree than for Feeder
1
, only nine (9) units on x-axis
172
to the left of y-axis
174
. For print media from feeder
124
(Feeder
2
), the computing device of printing device
100
is configured to adjust or shift the edge of the image to be printed by print engine
102
in printzone
129
to a greater degree than for Feeder
1
, twenty-six (26) units on x-axis
172
to the left of y-axis
174
. Even greater adjustment, thirty-five (35) units on x-axis
126
to the left of y-axis
174
, occurs for Feeder n. Each of these adjustments or shifts occurs automatically based only on the feeder from which the print media is supplied. No print medium edge sensing occurs each time the print medium is feed into printzone
129
which helps increase throughput of printing device
100
, as discussed above.
A graph
176
of probability distributions of the ranges of edges of supplies of print media in printzone
129
for each of feeders
122
,
124
,
126
, and
128
of printing device
100
after adjustment of where printing occurs in the printzone for each of feeders
122
,
124
,
126
, and
128
in accordance with the present invention is shown in FIG.
6
. As can be seen by comparing
FIGS. 5 and 6
, the overall adjusted range of variation of where image edge printing begins for printing device
100
, as shown in
FIG. 6
, is smaller than the unadjusted original overall range of variation shown in FIG.
5
. The adjusted range of variation is smaller because the present invention automatically adjusts or shifts the edge of the image to be printed by print engine
102
in printzone
129
of printing device
100
based on the determined median edge position for the particular feeder from which the print medium is being fed.
Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only, and is not to be taken necessarily, unless otherwise stated, as an express limitation. For example, although the probability distributions of the ranges of positions for the edges of the supplies of print media in the printzone were illustrated as Gaussian or normal, the present invention is configured to operate with other probability distributions as well. As another example, in one or more alternative embodiments of the present invention, edges
146
and
147
of print medium
140
may be detected by print medium edge sensor
138
and optical quadrature encoder strip
80
. From this edge information, the center of print medium
140
may be determined, as can the median position of the center of print medium
140
after transport of print medium
140
from print media input tray
28
to printzone
25
multiple times or transport of print medium
140
from print media input tray
41
to printzone
25
multiple times. Once this median position is determined, the position in printzone
25
for print medium
140
where printing composition is deposited can be adjusted based on this determined median position of the center of print medium
140
for each print media input tray or rack. It should be noted, that this alternative technique, in accordance with the present invention, may be applied as well to supplies of print media from respective feeders
122
,
124
,
126
, and
128
. The spirit and scope of the present invention are to be limited only by the terms of the following claims.
Claims
- 1. A method for use in a printing device, the printing device including a supply of print media and the printing device being configured to feed the supply of print media into a printzone where printing composition is deposited on the supply of print media, the method comprising:determining a range of positions of the supply of print media in the printzone; determining a median position of the supply of print media in the printzone; and adjusting a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
- 2. The method of claim 1, wherein the range of positions of an edge of the supply of print media in the printzone is determined, the median position of the edge of the supply of print media in the printzone is determined, and the position in the printzone for the supply of print media where printing composition is deposited is adjusted based on the determined median position of the edge of the supply of print media in the printzone.
- 3. The method of claim 1, wherein the supply of print media comprises at least one sheet of print media in a print media input tray.
- 4. A method for use in a printing device, the printing device including a first supply of print media and a second supply of print media, and the printing device being configured to selectively feed one of the first supply of print media into a printzone where printing composition is deposited on the first supply of print media and the second supply of print media into the printzone where printing composition is deposited on the second supply of print media, the method comprising:determining a range of positions of the first supply of print media in the printzone; determining a range of positions of the second supply of print media in the printzone; determining a median position of the first supply of print media in the printzone; determining a median position of the second supply of print media in the printzone; adjusting a position in the printzone for the first supply of print media where printing composition is deposited based on the determined median position of the first supply of print media in the printzone; and adjusting a position in the printzone for the second supply of print media where printing composition is deposited based on the determined median position of the second supply of print media in the printzone.
- 5. The method of claim 4, wherein the range of positions of an edge of the first supply of print media in the printzone is determined, the range of positions of an edge of the second supply of print media in the printzone is determined, the median position of the edge of the first supply of print media in the printzone is determined, the median position of the edge of the second supply of print media in the printzone is determined, the position in the printzone for the first supply of print media where printing composition is deposited is adjusted based on the determined median position of the edge of the first supply of print media in the printzone, and the position in the printzone for the second supply of print media where printing composition is deposited is adjusted based on the determined median position of the edge of the second supply of print media in the printzone.
- 6. The method of claim 4, wherein at least one of the first supply of print media and the second supply of print media comprise at least one sheet of print media in a print media input tray.
- 7. An apparatus for use in a printing device, the printing device including a supply of print media and the printing device being configured to feed the supply of print media into a printzone where printing composition is deposited on the supply of print media, the apparatus comprising:a sensor configured to detect the supply of print media and output a signal indicative of the detected supply of print media; and a computing device coupled to the sensor to receive the signal indicative of the detected supply of print media, the computing device being configured to determine a median position of the supply of print media in the printzone based on a plurality of trials of feeding the supply of print media into the printzone, and the computing device being further configured to adjust a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
- 8. The apparatus of claim 7, wherein the sensor is configured to detect an edge of the supply of print media and output a signal indicative of the detected edge of the supply of print media, and further wherein the computing device is configured to determine a median position of the edge of the supply of print media in the printzone based on a plurality of trials of feeding the supply of print media into the printzone, and the computing device is still further configured to adjust a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the edge of the supply of print media in the printzone.
- 9. The apparatus of claim 7, wherein the supply of print media comprises at least one sheet of print media in a print media input tray.
- 10. An apparatus for use in a printing device, the printing device including a plurality of supplies of print media and the printing device being configured to selectively feed any one of the supplies of print media into a printzone where printing composition is deposited on the selected supply of print media, the apparatus comprising:a sensor configured to detect each of the supplies of print media and output a signal indicative of each of the detected supplies of print media; and a computing device coupled to the sensor to receive the signal indicative of each of the supplies of print media, the computing device being configured to determine a median position of each of the supplies of print media in the printzone based on a plurality of trials of feeding each of the supplies of print media into the printzone, and the computing device being further configured to adjust a position in the printzone for each of the supplies of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
- 11. The apparatus of claim 10, wherein the sensor is configured to detect an edge of each of the supplies of print media and output a signal indicative of the detected edge of each of the supplies of print media, and further wherein the computing device is configured to determine a median position of the edge of each of the supplies of print media in the printzone based on a plurality of trials of feeding the supply of print media into the printzone, and the computing device is still further configured to adjust a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the edge of the supply of print media in the printzone.
- 12. The apparatus of claim 10, wherein at least one of the supplies of print media comprises at least one sheet of print media in a print media input tray.
- 13. An apparatus for use in a printing device, the printing device including a supply of print media and the printing device being configured to feed the supply of print media into a printzone where printing composition is deposited on the supply of print media, the apparatus comprising:means for determining a range of positions of the supply of print media in the printzone; means for determining a median position of the supply of print media in the printzone; and means for adjusting a position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
- 14. The apparatus of claim 13, wherein the means for determining a range of positions determines the range of positions of an edge of the supply of print media in the printzone, the means for determining a median position determines the median position of the edge of the supply of print media in the printzone, and the means for adjusting a position in the printzone adjusts the position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the edge of the supply of print media in the printzone.
- 15. The apparatus of claim 13, wherein the supply of print media comprises at least one sheet of print media in a print media input tray.
- 16. An apparatus for use in a printing device, the printing device including a plurality of supplies of print media and the printing device being configured to selectively feed any one of the supplies of print media into a printzone where printing composition is deposited on the selected supply of print media, the apparatus comprising:means for determining a range of positions of each of the supplies of print media in the printzone; means for determining a median position of each of the supplies of print media in the printzone; and means for adjusting a position in the printzone for each of the supplies of print media where printing composition is deposited based on the determined median position of the supply of print media in the printzone.
- 17. The apparatus of claim 16, wherein the means for determining a range of positions determines the range of positions of an edge of each of the supplies of print media in the printzone, the means for determining a median position determines the median position of the edge of each of the supplies of print media in the printzone, and the means for adjusting a position in the printzone adjusts the position in the printzone for the supply of print media where printing composition is deposited based on the determined median position of the edge of the supply of print media in the printzone.
- 18. The apparatus of claim 16, wherein at least one of the supplies of print media comprises at least one sheet of print media in a print media input tray.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5346202 |
Jurkewitz |
Sep 1994 |
A |
Foreign Referenced Citations (1)
Number |
Date |
Country |
360067349 |
Apr 1985 |
JP |