U.S. patent application number 09/853693 was filed with the patent office on 2002-01-24 for printing in selected record mode with reduced displacement of raster lines.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Mitsuzawa, Toyohiko.
Application Number | 20020008730 09/853693 |
Document ID | / |
Family ID | 18650099 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020008730 |
Kind Code |
A1 |
Mitsuzawa, Toyohiko |
January 24, 2002 |
Printing in selected record mode with reduced displacement of
raster lines
Abstract
The technique of the present invention enables a desired dot
record mode to be readily set for an individual dot recording
apparatus. The procedure generates first displacement data, which
represents deviations of dot recording position in a sub-scanning
direction intrinsic to respective dot forming elements, as well as
second displacement data, which represents errors of sub-scan feed.
The procedure then selects a desired dot record mode among a
plurality of dot record modes having identical resolution and
recording speed but different combinations of feeding amounts of
sub-scan, based on the first displacement data and the second
displacement data. The dot recording apparatus then carries out
main scan and sub-scan with a dot record head to record dots on a
printing medium in the selected dot record mode.
Inventors: |
Mitsuzawa, Toyohiko;
(Nagano-ken, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
SEIKO EPSON CORPORATION
Shinjuku-ku
JP
|
Family ID: |
18650099 |
Appl. No.: |
09/853693 |
Filed: |
May 14, 2001 |
Current U.S.
Class: |
347/40 |
Current CPC
Class: |
B41J 11/42 20130101;
B41J 2/2135 20130101; G06K 15/107 20130101; B41J 2202/10 20130101;
B41J 2202/17 20130101 |
Class at
Publication: |
347/40 |
International
Class: |
B41J 002/145 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2000 |
JP |
2000-143254(P) |
Claims
What is claimed is:
1. A dot recording apparatus that records dots on a surface of a
printing medium comprising: a dot record head having a plurality of
dot forming elements, which are used to form dots; a main scan
drive unit configured to carry out main scan, which shifts at least
one of the dot record head and the printing medium in a main
scanning direction; a sub-scan drive unit configured to carry out
sub-scan, which shifts at least one of the dot record head and the
printing medium in a sub-scanning direction perpendicular to the
main scanning direction; a first storage unit configured to store
first displacement data, the first displacement data substantially
representing deviations of dot recording positions in the
sub-scanning direction with respect to the plurality of dot forming
elements from a reference dot recording position by a reference dot
forming element selected among the plurality of dot forming
elements; a second storage unit configured to store second
displacement data, the second displacement data substantially
representing feeding errors of the sub-scan in the sub-scanning
direction; a record mode storage unit configured to store a
plurality of dot record modes, each of the dot record modes
specifying operations of the main scan and the sub-scan to record
dots, the plurality of dot record modes having a same dot
resolution and a substantially same recording speed but different
combinations of feeding amounts for the sub-scan carried out in
respective intervals of adjoining passes of the main scan; and a
control unit configured to control the respective units, wherein
the control unit comprises a selection unit that selects one dot
record mode among the plurality of dot record modes stored in the
record mode storage unit, based on the first displacement data and
the second displacement data.
2. A dot recording apparatus in accordance with claim 1, wherein
the dot record head is replaceable, and the first storage unit is
provided on the dot record head.
3. A dot recording apparatus in accordance with claim 1, wherein
the control unit controls the sub-scan drive unit, the main scan
drive unit, and the dot record head to repeatedly carry out the
sub-scan by a predetermined combination of feeding amounts in
respective intervals of adjoining passes of the main scan, and
thereby record dots on raster lines on the printing medium in each
of the dot record modes, the control unit further comprises: a
displacement calculation unit that calculates a sum of accumulated
feeding errors of the sub-scan with respect to each raster line of
interest before the raster line of interest on the printing medium
is recorded and a deviation of a dot recording position in the
sub-scanning direction by a dot forming element used for recording
the raster line of interest from the reference dot recording
position, and specifies the sum as a displacement of dot recording
position on each raster line, the selection unit calculates a
evaluation value relating to a variation in intervals of adjoining
raster lines in the sub-scanning direction, based on the
displacement of dot recording position on each raster line on the
printing medium, and selects the dot record mode according to the
evaluation value.
4. A dot recording apparatus in accordance with claim 3, wherein
the displacement calculation unit calculates the displacement of
dot recording position with regard to an equal number of raster
lines in each of the dot record modes.
5. A dot recording apparatus in accordance with claim 3, wherein
the displacement calculation unit calculates the displacement of
dot recording position with regard to raster lines to be recorded
while one set of the sub-scan is carried out by the combination of
feeding amounts for each dot record mode.
6. A dot recording apparatus in accordance with claim 3, further
comprises a sensor that reads a sub-scan-induced displacement
detection pattern printed on the printing medium for the purpose of
detecting a sub-scan-induced displacement in the sub-scanning
direction, wherein the control unit comprises: a sub-scan-induced
displacement detection pattern recording unit configured to control
the sub-scan drive unit, the main scan drive unit, and the dot
record head to record dots with an identical dot forming element in
each pass of the main scan while carrying out the sub-scan by the
combination of feeding amounts in respective intervals of the
adjoining passes of the main scan, so as to record the
sub-scan-induced displacement detection pattern in each dot record
mode; and a second displacement data generation unit that generates
the second displacement data, based on an output of the sensor.
7. A method of recording dots on a printing medium with a dot
record head having a plurality of dot forming elements, which are
used to form dots on the printing medium, by carrying out main scan
and sub-scan, where the main scan shifts at least one of the dot
record head and the printing medium in a main scanning direction
and the sub-scan shifts at least one of the dot record head and the
printing medium in a sub-scanning direction perpendicular to the
main scanning direction, the method comprising the steps of: (a)
generating first displacement data, which substantially represents
deviations of dot recording positions in the sub-scanning direction
with respect to the plurality of dot forming elements from a
reference dot recording position by a reference dot forming element
selected among the plurality of dot forming elements; (b)
generating second displacement data, which substantially represents
feeding errors of the sub-scan in the sub-scanning direction; (c)
selecting a dot record mode among a plurality of dot record modes,
based on the first displacement data and the second displacement
data, each of the dot record modes specifying operations of the
main scan and the sub-scan to record dots, the plurality of dot
record modes having a same dot resolution and a substantially same
recording speed but different combinations of feeding amounts for
the sub-scan carried out in respective intervals of adjoining
passes of the main scan; and (d) carrying out the main scan and the
sub-scan to record dots in the selected dot record mode.
8. A method in accordance with claim 7, wherein the step (d)
comprising the step of carrying out the sub-scan repeatedly by a
predetermined combination of feeding amounts in respective
intervals of adjoining passes of the main scan, and thereby records
dots on raster lines on the printing medium in the selected dot
record mode, and the step (c) comprising the steps of: (c1)
calculating a sum of accumulated feeding errors of the sub-scan
with respect to each raster line of interest before the raster line
of interest on the printing medium is recorded and a deviation of a
dot recording position in the sub-scanning direction by a dot
forming element used for recording the raster line of interest from
the reference dot recording position, and specifying the sum as a
displacement of dot recording position on each raster line; and
(c2) calculating a evaluation value relating to a variation in
intervals of adjoining raster lines in the sub-scanning direction,
based on the displacement of dot recording position on each raster
line on the printing medium, and selecting the dot record mode
according to the evaluation value.
9. A method in accordance with claim 8, wherein the step (c1)
comprising the step of calculating the displacement of dot
recording position with regard to an equal number of raster lines
in each of the dot record modes.
10. A method in accordance with claim 8, wherein the step (c1)
comprising the step of calculating the displacement of dot
recording position with regard to raster lines to be recorded while
one set of the sub-scan is carried out by the combination of
feeding amounts for each dot record mode.
11. A method in accordance with claim 7, wherein the step (d)
comprising the step of carrying out the sub-scan repeatedly by a
predetermined combination of feeding amounts in respective
intervals of adjoining passes of the main scan, and thereby records
dots on raster lines on the printing medium in the selected dot
record mode, and the step (b) comprising the steps of: (b1)
shifting the dot record head in a direction identical with the main
scanning direction and recording dots with an identical dot forming
element, while carrying out the sub-scan by the combination of
feeding amounts in respective intervals of adjoining shifts, so as
to record a sub-scan-induced displacement detection pattern in each
dot record mode; (b2) reading the sub-scan-induced displacement
detection pattern with a sensor; and (b3) generating the second
displacement data based on an output of the sensor.
12. A computer program product for selecting a dot record mode
using a computer, the computer being connected with a dot recording
apparatus, the dot recording apparatus being configured to record
dots on a surface of a printing medium, the dot recording apparatus
comprising: a dot record head having a plurality of dot forming
elements, which are used to form dots, and a scan drive unit
configured to carry out main scan and sub-scan, the main scan
shifting at least one of the dot record head and the printing
medium in a main scanning direction, the sub-scan shifting at least
one of the dot record head and the printing medium in a
sub-scanning direction perpendicular to the main scanning
direction, the computer program product comprising: a computer
readable medium; and a computer program stored on the computer
readable medium, the computer program comprising: a first program
for causing the computer to generate first displacement data, which
substantially represents deviations of dot recording positions in
the sub-scanning direction with respect to the plurality of dot
forming elements in the sub-scanning direction from a reference dot
recording position by a reference dot forming element selected
among the plurality of dot forming elements; a second program for
causing the computer to generate second displacement data, which
substantially represents feeding errors of the sub-scan in the
sub-scanning direction; a third program for causing the computer to
select one dot record mode among a plurality of dot record modes,
based on the first displacement data and the second displacement
data, each of the dot record modes specifying operations of the
main scan and the sub-scan to record dots, the plurality of dot
record modes having a same dot resolution and a substantially same
recording speed but different combinations of feeding amounts for
the sub-scan carried out in respective intervals of adjoining
passes of the main scan; and a fourth program for causing the
computer to carries out the main scan and the sub-scan to record
dots in the selected dot record mode.
13. A computer readable recording medium in accordance with claim
12, wherein the fourth program comprising a subprogram for carrying
out the sub-scan repeatedly by a predetermined combination of
feeding amounts in respective intervals of adjoining passes of the
main scan, and thereby records dots on raster lines on the printing
medium in the selected dot record mode, and the third program
comprising a first subprogram for calculating a sum of accumulated
feeding errors of the sub-scan with respect to each raster line of
interest before the raster line of interest on the printing medium
is recorded and a deviation of a dot recording position in the
sub-scanning direction by a dot forming element used for recording
the raster line of interest from the reference dot recording
position, and specifying the sum as a displacement of dot recording
position on each raster line; and a second subprogram for
calculating a evaluation value relating to a variation in intervals
of adjoining raster lines in the sub-scanning direction, based on
the displacement of dot recording position on each raster line on
the printing medium, and selecting the dot record mode according to
the evaluation value.
14. A computer readable recording medium in accordance with claim
13, wherein the first subprogram comprising a subprogram for
calculating the displacement of dot recording position with regard
to an equal number of raster lines in each of the dot record
modes.
15. A computer readable recording medium in accordance with claim
13, wherein the first subprogram comprising a subprogram for
calculating the displacement of dot recording position with regard
to raster lines to be recorded while one set of the sub-scan is
carried out by the combination of feeding amounts for each dot
record mode.
16. A computer readable recording medium in accordance with claim
12, wherein the fourth program comprising a subprogram for carrying
out the sub-scan repeatedly by a predetermined combination of
feeding amounts in respective intervals of adjoining passes of the
main scan, and thereby records dots on raster lines on the printing
medium in the selected dot record mode, and the second program
comprising; a subprogram for shifting the dot record head in a
direction identical with the main scanning direction and recording
dots with an identical dot forming element, while carrying out the
sub-scan by the combination of feeding amounts in respective
intervals of adjoining shifts, so as to record a sub-scan-induced
displacement detection pattern in each dot record mode; a
subprogram for reading the sub-scan-induced displacement detection
pattern with a sensor; and a subprogram for generating the second
displacement data based on an output of the sensor.
17. A method of manufacturing a printing apparatus by combining a
dot record head with a scan drive unit, the dot record head having
a plurality of dot forming elements, which are used to form dots on
a printing medium, the scan drive unit carrying out main scan and
sub-scan, where the main scan shifts at least one of the dot record
head and the printing medium in a main scanning direction and the
sub-scan shifts at least one of the dot record head and the
printing medium in a sub-scanning direction perpendicular to the
main scanning direction, the method comprising the steps of: (a)
generating first displacement data, which substantially represents
deviations of dot recording positions in the sub-scanning direction
with respect to the plurality of dot forming elements from a
reference dot recording position by a reference dot forming element
selected among the plurality of dot forming elements; (b)
generating second displacement data, which substantially represents
feeding errors of the sub-scan in the sub-scanning direction; (c)
attaching the dot record head to the scan drive unit; (d) selecting
a dot record mode among a plurality of dot record modes, based on
the first displacement data and the second displacement data, each
of the dot record modes specifying operations of the main scan and
the sub-scan to record dots, the plurality of dot record modes
having a same dot resolution and a substantially same recording
speed but different combinations of feeding amounts for the
sub-scan carried out in respective intervals of adjoining passes of
the main scan; and (e) storing the selected dot record mode in a
third storage unit provided in the printing apparatus.
18. A method in accordance with claim 17, wherein the printing
apparatus repeatedly carries out the sub-scan by a predetermined
combination of feeding amounts in respective intervals of adjoining
passes of the main scan, and thereby records dots on raster lines
on the printing medium in each of the dot record modes, and the
step (d) comprising the steps of: (d1) calculating a sum of
accumulated feeding errors of the sub-scan with respect to each
raster line of interest before the raster line of interest on the
printing medium is recorded and a deviation of a dot recording
position in the sub-scanning direction by a dot forming element
used for recording the raster line of interest from the reference
dot recording position, and specifying the sum as a displacement of
dot recording position on each raster line; and (d2) calculating a
evaluation value relating to a variation in intervals of adjoining
raster lines in the sub-scanning direction, based on the
displacement of dot recording position on each raster line on the
printing medium, and selecting the dot record mode according to the
evaluation value.
19. A method in accordance with claim 18, wherein the step (d1)
comprising the step of calculating the displacement of dot
recording position with regard to an equal number of raster lines
in each of the dot record modes.
20. A method in accordance with claim 18, wherein the step (d1)
comprising the step of calculating the displacement of dot
recording position with regard to raster lines to be recorded while
one set of the sub-scan is carried out by the combination of
feeding amounts for each dot record mode.
21. A method in accordance with claim 17, wherein the printing
apparatus repeatedly carries out the sub-scan by a predetermined
combination of feeding amounts in respective intervals of adjoining
passes of the main scan, and thereby records dots on raster lines
on the printing medium in each of the dot record modes, and the
step (b) comprising the steps of: (b1) shifting the dot record head
in a direction identical with the main scanning direction and
recording dots with an identical dot forming element, while
carrying out the sub-scan by the combination of feeding amounts in
respective intervals of adjoining shifts, so as to record a
sub-scan-induced displacement detection pattern in each dot record
mode; (b2) reading the sub-scan-induced displacement detection
pattern with a sensor; and (b3) generating the second displacement
data based on an output of the sensor.
22. A method in accordance with claim 17, wherein the step (a)
comprising the steps of: (a1) driving each of the dot forming
elements while shifting the dot record head in a direction
identical with the main scanning direction, so as to print a
head-induced displacement detection pattern; (a2) reading the
head-induced displacement detection pattern with a sensor; and (a3)
generating the first displacement data based on an output of the
sensor.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a technique of recording
dots on the surface of a printing medium, so as to print an
image.
[0003] 2. Description of the Related Art
[0004] Typical examples of the dot recording apparatus that records
dots while scanning a dot record head in a main scanning direction
and in a sub-scanning direction include serial scan printers and
drum scan printers. Parameters defining the dot recording mode in
such printers include the number of nozzles used for printing with
regard to one color, the nozzle pitch, and the feeding amounts of
sub-scan. One printer may adopts a plurality of different dot
recording modes having different settings for some of these
parameters.
[0005] Pixels, which are the measure for defining the dot recording
position, are virtually arranged along the width and the length of
a printing medium. An array of pixels arranged in the main scanning
direction on the printing medium is called a raster line. For the
high-quality printing result, it is desirable to record dots on the
respective raster lines at equal intervals in the sub-scanning
direction. The manufacturing error of an individual dot recording
apparatus may, however, cause the dots on the respective raster
lines to be not recorded at equal intervals in the sub-scanning
direction. One proposed technique disclosed in JP10-337864A selects
the dot recording mode suitable for each dot recording apparatus,
which has a little variation in dot array interval in the
sub-scanning direction, among a plurality of dot recording modes by
taking into account the manufacturing error of the dot recording
apparatus.
[0006] This prior art technique measures the distance between
raster lines actually recorded in each dot recording mode and
selects a desired dot recording mode based on the measurement
results. This method records linear ruled lines on the raster lines
with regard to all the possible combinations of nozzles that may
record adjoining raster lines. The method of actually printing the
ruled lines with regard to all the combinations of the nozzles and
the sub-scan feeds in the respective dot recording modes is a heavy
load and takes a significantly long time.
SUMMARY OF THE INVENTION
[0007] The object of the present invention is thus to provide a
technique that enables a desired dot record mode to be readily set
in an individual dot recording apparatus.
[0008] In order to attain at least part of the above and other
objects, the present invention applies some technique to recording
dots on a printing medium with a dot record head having a plurality
of dot forming elements, which are used to form dots on the
printing medium, by carrying out main scan and sub-scan, where the
main scan shifts at least one of the dot record head and the
printing medium in a main scanning direction and the sub-scan
shifts at least one of the dot record head and the printing medium
in a sub-scanning direction perpendicular to the main scanning
direction. First displacement data is generated which substantially
represents deviations of dot recording positions in the
sub-scanning direction with respect to the plurality of dot forming
elements from a reference dot recording position by a reference dot
forming element selected among the plurality of dot forming
elements. Second displacement data is also generated which
substantially represents feeding errors of the sub-scan in the
sub-scanning direction. Then a dot record mode is selected among a
plurality of dot record modes, based on the first displacement data
and the second displacement data, each of the dot record modes
specifying operations of the main scan and the sub-scan to record
dots, the plurality of dot record modes having a same dot
resolution and a substantially same recording speed but different
combinations of feeding amounts for the sub-scan carried out in
respective intervals of adjoining passes of the main scan. Then the
main scan and the sub-scan are carried out to record dots in the
selected dot record mode.
[0009] This arrangement enables a deviation of dot recording
position on each raster line to be checked easily without actually
recording dots on the raster line. The optimum dot record mode is
then selected, based on the information regarding the displacement
of dot recording position.
[0010] When the dot record head is replaceable, it is preferable
that the first displacement data is stored in the first storage
unit provided on the dot record head. Even when the dot record head
is replaced with a new one, this arrangement enables a desired dot
record mode suitable for the new dot record head to be
selected.
[0011] One applicable dot recording method carries out the sub-scan
by a predetermined combination of feeding amounts in respective
intervals of adjoining sub-scan feeds, so as to record dots on each
raster line on the printing medium. In this dot recording method,
it is preferable that the dot record mode is selected according to
the procedure discussed below. A sum of accumulated feeding errors
of the sub-scan and a deviation of a dot recording position in the
sub-scanning direction is calculated. The accumulated feeding
errors of the sub-scan is the errors with respect to each raster
line of interest efore the raster line of interest on the printing
medium is recorded. The deviation of a dot recording position in
the sub-scanning direction is the deviation by a dot forming
element used for recording the raster line of interest from the
reference dot recording position. The sum is specified as a
displacement of dot recording position on each raster line. A
evaluation value relating to a variation in intervals of adjoining
raster lines in the sub-scanning direction is calculated based on
the displacement of dot recording position on each raster line on
the printing medium, and selecting the dot record mode according to
the evaluation value.
[0012] This arrangement enables the displacement of dot recording
position to be calculated with high accuracy from the feeding
errors of sub-scan and the deviation of the dot recording position
with regard to the corresponding dot forming element.
[0013] It is preferable that the displacement of dot recording
position is calculated with regard to an equal number of raster
lines in each of the dot record modes. This application ensures the
accurate evaluation of the displacement and the selection of the
appropriate dot record mode even when the evaluation value is
affected by the number of samples.
[0014] The displacement of dot recording position may be calculated
with regard to raster lines to be recorded while one set of the
sub-scan is carried out by the combination of feeding amounts for
each dot record mode. When the respective feeding amounts of
sub-scan included in the combination set for each dot record mode
have intrinsic errors, the arrangement of calculating the
displacement of dot recording position on each of the above raster
lines ensures the appropriate evaluation of the displacement in
each dot record mode.
[0015] The second displacement data may be generated according to
the following procedure. The dot record head is shifted in a
direction identical with the main scanning direction and recording
dots with an identical dot forming element, while carrying out the
sub-scan by the combination of feeding amounts in respective
intervals of adjoining shifts, so as to record a sub-scan-induced
displacement detection pattern in each dot record mode. The
sub-scan-induced displacement detection pattern is read with a
sensor. Then the second displacement data is generated based on an
output of the sensor.
[0016] This application enables the feeding errors of sub-scan to
be evaluated based on the actual printing result. Since the
identical dot forming element is used to record dots, the net
feeding errors of sub-scan can be evaluated adequately.
[0017] The first displacement data may be generated according to
the following procedure. Each of the dot forming elements are
driven while shifting the dot record head in a direction identical
with the main scanning direction, so as to print a head-induced
displacement detection pattern. The head-induced displacement
detection pattern is read with a sensor. Then the first
displacement data is generated based on an output of the
sensor.
[0018] This application enables the deviations of the dot recording
positions in the sub-scanning direction with regard to the
respective dot forming elements to be evaluated based on the actual
printing result. Since dots are recorded without any sub-scan, the
net deviations of the dot recording positions intrinsic to the
respective dot forming elements can be evaluated adequately.
[0019] The technique of the present invention may be actualized by
any of various applications listed below:
[0020] (1) a printing apparatus and a printing control
apparatus;
[0021] (2) a printing method, a printing control method, and a
method of manufacturing the printing apparatus;
[0022] (3) a dot record head;
[0023] (4) a method of manufacturing the dot record head;
[0024] (5) a computer program for actualizing any of the above
apparatuses and methods;
[0025] (6) a recording medium in which the computer program for
actualizing any of the above apparatuses and methods is recorded;
and
[0026] (7) a data signal that includes the computer program for
actualizing any of the above apparatuses and methods and is
embodied in a carrier wave.
[0027] These and other objects, features, aspects, and advantages
of the present invention will become more apparent from the
following detailed description of the preferred embodiments with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a block diagram illustrating the structure of an
image processing system in one embodiment of the present
invention;
[0029] FIG. 2 schematically illustrates the structure of a color
printer included in the image processing system;
[0030] FIGS. 3A and 3B show an arrangement of ink jet nozzles on
ink ejection heads of a print head in the color printer of FIG.
2;
[0031] FIG. 4 is a functional block diagram showing the structure
relating to drive control operations according to a dot record
mode;
[0032] FIG. 5 shows a first dot recording mode at k=4;
[0033] FIGS. 6A and 6B show scanning parameters in the first dot
recording mode at k=4 and effective raster line numbers allocated
to effective raster lines recorded with respective nozzles;
[0034] FIG. 7 shows nozzle numbers allocated to the nozzles used
for recording the effective raster lines in the first dot recording
mode at k=4;
[0035] FIGS. 8A and 8B show scanning parameters in a second dot
recording mode at k=4 and effective raster line numbers allocated
to effective raster lines recorded with respective nozzles;
[0036] FIG. 9 shows nozzle numbers allocated to the nozzles used
for recording the effective raster lines in the second dot
recording mode at k=4;
[0037] FIG. 10 is a flowchart showing a procedure of manufacturing
a printing apparatus;
[0038] FIG. 11 is a flowchart showing the details of the process of
generating first displacement data at step S1 in the flowchart of
FIG. 10;
[0039] FIG. 12 shows an example of head-induced displacement
detection pattern recorded at step S11 in the flowchart of FIG. 11
and a process of reading the head-induced displacement detection
pattern;
[0040] FIG. 13 is a flowchart showing the details of the process of
generating second displacement data at step S2 in the flowchart of
FIG. 10;
[0041] FIG. 14 shows an example of sub-scan-induced displacement
detection pattern recorded at step S21 and a process of reading the
sub-scan-induced displacement detection pattern;
[0042] FIG. 15 shows the relations among a displacement calculation
unit included in a computer, which is part of the equipment for
manufacturing printers, a head ID memory on the print head, and a
sub-scan displacement memory included in a scan drive unit;
[0043] FIG. 16 is a flowchart showing another procedure of
manufacturing the printing apparatus;
[0044] FIG. 17 is a flowchart showing the details of the process of
generating the first displacement data at step S1a in the flowchart
of FIG. 16;
[0045] FIG. 18 is a flowchart showing the details of the process of
generating the second displacement data at step S2a in the
flowchart of FIG. 16;
[0046] FIG. 19 is a flowchart showing the details of the process of
calculating the evaluation value with regard to each dot record
mode at step S5a in the flowchart of FIG. 16;
[0047] FIG. 20 shows the principle of calculating a dot array
interval between adjoining raster lines as the evaluation
value;
[0048] FIG. 21 is a flowchart showing a procedure of determining
the dot record mode after attachment of the print head to the scan
drive unit;
[0049] FIG. 22 is a block diagram showing the structure of another
printer driver that includes a mode specification unit as a
functional unit thereof;
[0050] FIG. 23 is a block diagram showing the structure of still
another printer driver that includes a first displacement data
generation unit and a head-induced displacement detection pattern
recording unit as functional units thereof; and
[0051] FIG. 24 is a block diagram showing the structure of another
printer driver that includes a second displacement data generation
unit and a sub-scan-induced displacement detection pattern
recording unit as functional units thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] Embodiments of the present invention will be described in
the following order:
[0053] A. Structure of Printing Apparatus
[0054] B. Various Dot recording modes
[0055] C. Manufacture of Printer (Method of Setting Displacement
Data)
[0056] D. Another Method of Setting Displacement Data
[0057] E. Other Modifications
[0058] A. Structure of Printing Apparatus
[0059] FIG. 1 is a block diagram illustrating the structure of an
image processing system in one embodiment of the present invention.
The image processing system includes a scanner 12, a personal
computer 90, and a color printer 22. The personal computer 90 has a
color display 21. The scanner 12 reads color image data from a
color original and supplies original color image data ORG composed
of three color components, R, G, and B, to the computer 90.
[0060] The computer 90 includes a CPU, a RAM, and a ROM, and other
constituents (none of them is shown). In the computer 90, an
application program 95 works under the control of a predetermined
operating system. A video driver 91 and a printer driver 96 are
incorporated in the operating system. The application program 95
outputs final color image data FNL via these drivers 91 and 96. The
application program 95, which carries out series of processing like
generation and retouching of images, inputs an original image read
by the scanner 12, makes the input image subject to a predetermined
series of processing, and causes a resulting processed image to be
displayed on the color display 21 via the video driver 91. In
response to a printing instruction output from the application
program 95, the printer driver 96 in the computer 90 receives image
information from the application program 95 and converts the image
information to signals printable by the printer 22 (in this
embodiment, binarized signals with regard to the respective colors,
C, M, Y, and K, used in the printer 22). In the structure of the
embodiment shown in FIG. 1, the printer driver 96 includes a
rasterizer 97 that converts color image data processed by the
application program 95 to image data of a printing resolution, a
color correction modules 98 that converts the image data to another
image data including color components for the ink colors C, M, Y
used in the printer 22, and a color correction table CT that is
referred to by the color correction module 98. The printer driver
96 further includes a halftone module 99 that generates halftone
image data, which expresses the density of the image according to
the presence or absence of ink at each dot position, based on the
color corrected image data. The printer driver 96 also includes a
print mode setting module 110 that functions to write print mode
selection information (discussed later) into a memory of the color
printer 22.
[0061] FIG. 2 schematically illustrates the structure of the
printer 22. The printer 22 has a sub-scan mechanism of driving a
sheet feed motor 23 to feed a sheet of printing paper P, a main
scan mechanism of driving a carriage motor 24 to move a carriage 31
forward and backward along an axis of a platen 26, a head driving
mechanism of driving a print head 28 mounted on the carriage 31 to
implement ink ejection and dot creation, and a control circuit 40
that controls transmission of signals to and from the sheet feed
motor 23, the carriage motor 24, the print head 28, and a control
panel 32.
[0062] A black ink cartridge 71 for black ink (K) and a color ink
cartridge 72 in which three color inks, that is, cyan (C), magenta
(M), and yellow (Y), are accommodated are detachably attached to
the carriage 31 in the printer 22. A total of four ink ejection
heads 61 through 64 are formed on the print head 28 that is
disposed in the lower portion of the carriage 31. Ink conduits (not
shown) are formed in the bottom of the carriage 31 to lead supplies
of inks from ink reservoirs to the respective ink ejection heads.
When the ink cartridges 71 and 72 are pressed down to the carriage
31, the ink conduits are fitted in connection ports formed in the
respective ink cartridges, so that the supplies of the respective
color inks are flown into the corresponding ink ejection heads 61
through 64.
[0063] FIG. 3A shows an arrangement of ink ejection nozzles in the
respective ink ejection heads 61 through 64. The first ink ejection
head 61 has a nozzle array for black ink. The second through the
fourth ink ejection heads 62 through 64 respectively have nozzle
arrays for cyan, magenta, and yellow inks. The four nozzle arrays
are mounted at an identical sub-scanning position.
[0064] Each of the four nozzle arrays includes a plurality of
nozzles (dot forming elements) n arranged in zigzag at a fixed
nozzle pitch k in the sub-scanning direction. An ink particle Ip is
ejected at a high speed from each nozzle n. The ink particles Ip
soak into the printing paper P set on the platen 26, so as to form
dots as shown in FIG. 3B and implement printing. The plurality of
nozzles n included in each nozzle array may be arranged in
alignment, instead of in zigzag. The zigzag arrangement shown in
FIG. 3A, however, has an advantage that the nozzle array can be
designed to have a small nozzle pitch k.
[0065] The printer 22 drives the sheet feed motor 23 to rotate the
platen 26 and other related rollers to thereby feed the printing
paper P. The printer 22 also drives the carriage motor 24 to move
the carriage 31 back and forth, and simultaneously actuates
piezoelectric elements provided in the respective ink ejection
heads 61 through 64 of the print head 28 to eject the respective
inks. These procedures enable a multi-color image to be printed on
the printing paper P.
[0066] The mechanism of feeding the printing paper P has a gear
train (not shown) that transmits the rotations of the sheet feed
motor 23 to the platen 26 and a sheet feed roller (not shown). The
mechanism of reciprocating the carriage 31 includes a sliding shaft
34 that is arranged in parallel with the axis of the platen 26 to
support the carriage 31 in a slidable manner, a pulley 38 that is
combined with the carriage motor 24 to support an endless drive
belt 36 spanned therebetween, and a position sensor 39 that detects
the carriage 31 at its reference position.
[0067] The control circuit 40 includes a programmable ROM (PROM) 42
as a rewritable non-volatile memory as shown in FIG. 2, in addition
to a CPU and main memories like a ROM and a RAM (not shown). PROM
42 stores dot record mode information including parameters with
regard to a plurality of dot record modes. Here the "dot record
mode" represents a dot recording mode defined by the number of
working nozzles N in each nozzle array actually used for printing
and the sub-scan feed amount L. In the specification hereof, the
term "recording process" is substantially synonymous with the terms
"record mode" and "printing mode". Concrete examples of the dot
record mode and their parameters will be discussed later. PROM 42
also stores print mode selection information, which is used to
select a desired dot record mode among the plurality of dot record
modes. For example, in the case where dot record mode information
of 16 modes can be stored in the PROM 42, the print mode selection
information is 4-bit data.
[0068] The dot record mode information is read from the PROM 42 by
the printer driver 96 (see FIG. 1), when the printer driver 96 is
installed on the start of the computer 90. The printer driver 96
reads the dot record mode information corresponding to a desired
dot record mode specified by the print mode selection information
from the PROM 42. The series of processing by the rasterizer 97 and
the halftone module 99 and the main scan and sub-scan operations
are carried out according to the input dot record mode
information.
[0069] PROM 42 may be any rewritable non-volatile memory, and a
diversity of non-volatile memories like an EEPROM and a flash
memory may be applicable for the PROM 42. While it is preferable
that the print mode selection information is stored in the
rewritable non-volatile memory, the dot record mode information may
be stored in a non-rewritable ROM. The dot record mode information
may be stored in a storage unit other than the PROM 42 or may
alternatively be registered in the printer driver 96.
[0070] FIG. 4 is a functional block diagram showing the structure
relating to drive control operations according to the dot record
mode. The functional block diagram includes a mode selection memory
220, a record mode setting unit 204, a record mode table 206, a
drive unit controller 208, a main scan drive unit 210, a sub-scan
drive unit 212, a print head drive unit 214, a raster data storage
unit 216, the print head 28, and the printing paper P. The mode
selection memory 220 and the record mode table 206 respectively
correspond to the third storage unit and the record mode storage
unit of the present invention.
[0071] The mode selection memory 220 stores the print mode
selection information that is used to specify a desired dot record
mode. The record mode table 206 stores the dot record mode
information representing a plurality of dot record modes. The dot
record mode information includes a printing resolution, a mode
class, a record mode number allocated to each record mode, the
number of working nozzles N, and the sub-scan feed amount L. The
printing resolution represents the resolution of dots recorded on
the printing paper P. The mode class specifies one of the two
classes "Fast" and "Fine". For example, the "Fine" mode class is an
overlap record mode that causes each raster line to be recorded
with a plurality of nozzles. The "Fast" mode class is not an
overlap record mode and is the mode that causes each raster line to
be recorded with each nozzle by one pass of the main scan. In the
example of FIG. 4, three dot record modes are registered for the
"720 dpi, Fine" mode. Record mode numbers 1, 2, and 3 are allocated
to these dot record modes. The number of working nozzles N
represents the number of nozzles actually used for printing. The
sub-scan feed amount L represents the number of dot spaces by which
the printing paper P is fed in the course of sub-scan. The dot
record mode information also includes a variety of other parameters
for specifying the main scan and sub-scan operations, although such
parameters are omitted from the illustration of FIG. 4.
[0072] The record mode setting unit 204 sends parameters, which
specify the main scan and sub-scan operations, to the drive unit
controller 208 and the raster data storage unit 216 according to
the print data transmitted from the computer 90 and the print mode
selection information transmitted from the mode selection memory
220 in the PROM 42. The print data here is the same as the final
color image data FNL shown in FIG. 1. A header portion (not shown)
of the print data includes data representing the printing
resolution and the mode class. The record mode setting unit 204
specifies the dot record mode used for printing, based on the
printing resolution, the mode class, and the print mode selection
information transmitted from the mode selection memory 220. The
plural dot record modes as possible options are registered only for
the "720 dpi, Fine" mode in the example of FIG. 4. As for the other
combinations of the mode class and the printing resolution, one dot
record mode is specified only based on the printing resolution and
the mode class regardless of the print mode selection
information,.
[0073] The record mode setting unit 204 transmits the scanning
parameters, which include the number of working nozzles N and the
sub-scan feed amount L, with regard to the dot record mode thus
specified to the drive unit controller 208 and the raster data
storage unit 216. As discussed later, the number of working nozzles
N and the sub-scan feed amount L may be varied on each pass of the
scan. The scanning parameters including the number of working
nozzles N and the sub-scan feed amount L are thus transmitted to
the drive unit controller 208 and the raster data storage unit 216,
prior to each pass of the main scan.
[0074] The raster data storage unit 216 stores the print data into
a non-illustrated buffer memory according to the scanning
parameters including the number of working nozzles N and the
sub-scan feed amount L. The drive unit controller 208 controls the
main scan drive unit 210, the sub-scan drive unit 212, and the
print head drive unit 214 according to these scanning parameters
including the number of working nozzles N and the sub-scan feed
amount L.
[0075] The record mode table 206 and the mode selection memory 220
are provided in the PROM 42. The record mode setting unit 204, the
drive unit controller 208, and the raster data storage unit 216 are
provided in the control circuit 40 shown in FIG. 2. The main scan
drive unit 210 is actualized by the feeding mechanism of the
carriage 31 including the carriage motor 24 shown in FIG. 2. The
sub-scan drive unit 212 is actualized by the feeding mechanism of
the printing paper P including the sheet feed motor 23. The print
head drive unit 214 is actualized by a circuit including
piezoelectric elements allocated to the respective nozzles.
[0076] B. Various Dot Recording Modes
[0077] FIG. 5 shows a first dot recording mode at the dot pitch k
equal to 4 dots. The scanning parameters in the first dot recording
mode are the nozzle pitch k=4 dots, the number of working nozzles
N=8, the number of scan repeats s=1, and the number of effective
nozzles Neff=8 as shown in the bottom of FIG. 5. The number of sub
scan feeds s denotes the number of main scan passes performed to
complete dot formation on each raster line. The number of effective
nozzles Neff is obtained by dividing the number of working nozzles
N by the numbers of scan repeats s.
[0078] In the example of FIG. 5, nozzle numbers #0 through #7 are
sequentially allocated to the eight working nozzles. In the first
dot recording mode at k=4, one cycle includes four sub-scan feeds
that respectively have the sub-scan feed amount L of 10, 7, 6, and
9 dots. Namely a plurality of different values are set to the
sub-scan feed amount L in one cycle of sub-scan feeds. The
positions of the eight working nozzles after the respective
sub-scan feeds are shown by four different symbols. The right side
drawing of FIG. 5 shows the dots on respective raster lines in an
effective recording area recorded with the nozzles after the
respective sub-scan feeds. The effective recording area denotes an
area in which all raster lines can be recorded without any line
skip. In contrast, an areas in which some raster line cannot
recorded is referred to as "non-effective recording area." In the
first dot recording mode at k=4, a non-effective recording area of
20 raster line spaces is present prior to the effective recording
area. In other words, the effective recording area starts at the
21.sup.st raster line from the upper end of a nozzle scanning area
(that is, the total area including both the effective recording
area and the non-effective recording area). The position of the
nozzles in the first pass of main scan is set at a predetermined
distance from the upper end of the printing paper. The earlier and
upper starting of the effective recording area thus enables
recording of dots to begin at the position closer to the upper end
of the printing paper.
[0079] FIG. 6A shows the scanning parameters in the first dot
recording mode at k=4. The table of FIG. 6A shows the sub-scan feed
amount L, the summation thereof .SIGMA.L, and the offset F of the
nozzles after each pass of sub-scan.
[0080] FIG. 6B shows effective raster line numbers allocated to
effective raster lines recorded with the respective nozzles in the
main scan after each pass of sub-scan in the first dot recording
mode at k=4. The left end column in the table of FIG. 6B shows the
nozzles numbers #0 through #7. The numbers in the other columns
represent which raster lines in the effective recording area are
recorded with these nozzles #0 through #7 after the 0.sup.th pass
to the 7.sup.th pass of sub-scan. For example, in the main scan
after the 0.sup.th pass of sub-scan (that is, the first pass of
main scan to record the effective recording area), the nozzles #5
through #7 respectively record the 1.sup.st, 5.sup.th, and 9.sup.th
effective raster lines. In the main scan after the 1.sup.st pass of
sub-scan, the nozzles #3 through #7 respectively record the
3.sup.rd, 7.sup.th, 11.sup.th, 15.sup.th, and 19.sup.th effective
raster lines. Here the effective raster lines represent raster
lines in the effective recording area.
[0081] In the example of FIG. 6B, the effective raster lines
recorded in one identical pass of main scan are present at
intervals of the nozzle pitch k (=4). One cycle of the main scan
accordingly records N.times.k (=32 in this example) raster lines.
The nozzles are arranged at the intervals of the nozzle pitch k, so
that the 32 raster lines recorded in one cycle are not consecutive
as clearly understood from FIG. 5. The table of FIG. 6B shows which
nozzles are used to record the first 32 raster lines in the
effective recording area.
[0082] In the table of FIG. 6B, the effective raster line numbers
expressed by the bracketed numerals show that raster lines at the
equivalent positions to those of the bracketed raster lines under
the current scanning conditions have been recorded in a previous
cycle. The value obtained by subtracting 32 from the bracketed
numeral represents the effective raster line number allocated to
the equivalent raster line. For example, the effective raster line
No. 36 recorded with the nozzle #0 is the raster line at the
equivalent position to that of the effective raster line No. 4
under the current scanning conditions.
[0083] FIG. 7 shows the nozzle numbers allocated to the nozzles
used for recording the effective raster lines in the first dot
recording mode at k=4. The numerals 1 through 31 in the left end
column of FIG. 7 represent the effective raster line numbers. The
right side columns show the effective raster lines recorded with
the 8 working nozzles #0 through #7 in the main scan after the
respective sub-scan feeds. For example, in the main scan after
0.sup.th pass of sub-scan, the nozzles #5 through #7 respectively
record the 1.sup.st, 5.sup.th, and 9.sup.th effective raster lines.
The comparison between FIG. 7 and FIG. 6B clearly shows the
relationship between the effective raster line number and the
nozzle number.
[0084] The four different symbols .cndot., .times., .Arrow-up
bold., .dwnarw. appearing in the second left column of@in FIG. 7
show whether or not adjoining raster lines have already been
recorded at the time when each raster line of interest is recorded.
These symbols have the following meanings:
[0085] .dwnarw.: Only the adjoining raster line after the raster
line of interest has already been recorded;
[0086] .Arrow-up bold.: Only the adjoining raster line before the
raster line of interest has already been recorded;
[0087] .times.: Both the adjoining raster lines before and after
the raster line of interest have already been recorded; and
[0088] .cndot.: Neither of the adjoining raster lines before and
after the raster line of interest have not yet been recorded.
[0089] The presence or the absence of the record of the adjoining
raster lines before and after each raster line of interest affects
the picture quality of the raster line of interest that is
currently recorded. The picture quality is affected by the drying
degree of ink on the adjoining recorded raster lines and by the
errors of sub-scan feed. The appearance of the pattern@defined by
the above four symbols at a relatively large period on the printing
paper may deteriorate the picture quality of the resulting printed
image. In the first dot recording mode shown in FIG. 7, the
pattern@defined by the four symbols does not show any clear
periodicity. It is accordingly expected that the resulting recorded
image is not subject to significant deterioration of the picture
quality due to the periodic pattern but has relatively good picture
quality.
[0090] The value .DELTA. in the third left column of FIG. 7 shows
the maximum number of sub-scan feeds between recording of an
adjoining raster line and recording of each raster line of
interest. This value A is hereinafter called "the differential
number of sub-scans." For example, the 2.sup.nd effective raster
line is recorded with the nozzle #1 after the 2.sup.nd pass of
sub-scan, whereas the 1.sup.st effective raster line is recorded
with the nozzle #5 after the 0.sup.th pass of sub-scan. Namely the
2.sup.nd raster line has the differential number of sub-scan feeds
.DELTA.=2. In a similar manner, there are 3 sub-scan feeds between
recording of the 5.sup.th effective raster line and recording of
the 4.sup.th effective raster line. The 4.sup.th effective raster
line accordingly has the differential number of sub-scan feeds
.DELTA.=3.
[0091] One cycle includes k (=4) sub-scan feeds. The differential
number of sub-scan feeds .DELTA. thus ranges from 0 to k. In the
first dot recording mode at k=4, the maximum differential number of
sub-scan feeds .DELTA. is equal to 3. This is smaller than the
upper limit k (=4).
[0092] It is ideal that the actual sub-scan feed amount is an exact
integral multiples of the dot pitch. In the actual state, however,
there are some feeding errors. The errors of sub-scan feed are
accumulated on each pass of sub-scan. In the case where many
sub-scan feeds are interposed between two passes of main scan for
recording two adjoining raster lines, there may be a displacement
of raster lines due to the accumulated errors of sub-scan feed
between the two adjoining raster lines. As described above, the
differential number of sub-scan feeds .DELTA. shown in FIG. 7
represents the number of sub-scan feeds between recording of an
adjoining raster line and recording of each raster line of
interest. The smaller differential number of sub-scan feeds .DELTA.
is preferable to reduce the displacement of adjoining raster lines
due to the accumulated errors of sub-scan feed. In the first dot
recording mode at k=4 shown in FIG. 7, the differential number of
sub-scan feeds .DELTA. is not greater than 3, which is smaller than
the upper limit 4. This characteristic also ensures the favorable
picture quality of the resulting image recorded by the first dot
recording mode at k=4.
[0093] FIG. 8 shows scanning parameters in a second dot recording
mode at k=4 and effective raster line numbers allocated to
effective raster lines recorded with the respective nozzles. This
corresponds to FIG. 5 in the first dot recording mode at k=4. The
second dot recording mode and the first dot recording mode at k=4
have the same nozzle pitch k and the same number of effective
nozzles Neff and thus enable an image to be recorded at a same
resolution [dpi] and a same recording speed. The difference between
the first dot recording mode and the second dot recording mode at
k=4 is only the sequence of the variation in sub-scan feed amount
L. In the first dot recording mode at k=4, the sub-scan feed amount
L varies as 10, 7 6, and 9 dot spaces in this order. In the second
dot recording mode at k=4, on the other hand, the sub-scan feed
amount L varies as 7, 6, 9, and 10 dot spaces in this order.
[0094] Like the first dot recording mode at k=4, the second dot
recording mode at k=4 has two characteristics. First, the nozzle
pitch k and the number of working nozzles N are integers that are
not less than 2 and are not prime to each other. Second, a
plurality of different values are set to the sub-scan feed amount
L.
[0095] FIG. 9 shows the nozzle numbers allocated to the nozzles
used for recording the effective raster lines in the second dot
recording mode at k=4. This corresponds to FIG. 7 in the first dot
recording mode at k=4. As in the case of the first dot recording
mode at k=4 shown in FIG. 7, in the second dot recording mode at
k=4 shown in FIG. 9, the pattern@defined by the four different
symbols, which represent the presence or absence of recorded
adjoining raster lines at the time when each raster line of
interest is recorded, does not have any clear periodicity. It is
accordingly expected that the resulting recorded image have
relatively good picture quality. In the second dot recording mode
at k=4, the differential number of sub-scan feeds .DELTA. is also
not greater than 3. This causes the smaller accumulated errors of
sub-scan feed and thus ensures the favorable picture quality of the
resulting image recorded by the second dot recording mode at
k=4.
[0096] As described above, the first dot recording mode and the
second dot recording mode at k=4 have the first characteristic that
the nozzle pitch k and the number of working nozzles N are integers
that are not less than 2 and are not prime to each other, and the
second characteristic that a plurality of different values are set
to the sub-scan feed amount L. There may be a large number of
equivalent dot recording modes having different sequences of the
variation in sub-scan feed amount L. In the case where there are a
plurality of equivalent dot recording modes having different
sequences of the variation in sub-scan feed amount L but identical
resolution and recording speed, which of the equivalent dot
recording modes attains the highest picture quality depends upon
the individual printers. This is because the picture quality of the
image recorded by each printer is affected by the combination of
errors caused by the manufacture of the printer (for example, the
errors of the nozzle pitch and the errors of sub-scan feed) with
the adopted scanning method in the dot recording mode (mainly the
set of feeding amounts of sub-scan). When there are a plurality of
equivalent dot recording modes having different sequences of the
variation in sub-scan feed amount like the first and the second dot
recording modes discussed above, it is preferable to select the
optimum dot recording mode that attains the highest picture quality
with regard to each printer.
[0097] C. Manufacture of Printer (Method of Setting Displacement
Data)
[0098] FIG. 10 is a flowchart showing a procedure of manufacturing
the printing apparatus. The procedure first manufactures the print
head 28 at step S1 and a scan drive unit at step S2. The scan drive
unit is a part of the color printer 22 including the main scan
drive unit 210 and the sub-scan drive unit 212. As mentioned
previously, the main scan drive unit 210 is actualized by the
feeding mechanism of the carriage 31 including the carriage motor
24, and the sub-scan drive unit 212 is actualized by the feeding
mechanism of the printing paper P including the sheet feed motor 23
(see FIG. 2). The procedure of step S1 generates first displacement
data in the course of manufacturing the print head 28. The first
displacement data substantially represents deviations of the dot
recording positions in the sub-scanning direction by the other
nozzles from the dot recording position by a reference nozzle #7
(hereinafter may be referred to as the vertical displacement). The
procedure of step S2 generates second displacement data, which
substantially represents errors of sub-scan feed in the
sub-scanning direction, in the course of manufacturing the scan
drive unit. The processes of generating the first and second
displacement data will be discussed in detail later.
[0099] The procedure attaches the print head 28 to the scan drive
unit at step S3, and calculates a displacement of dot recording
position on each raster line in each dot record mode at step S4.
The procedure then calculates an evaluation value of each dot
record mode from the calculated displacement on the raster line at
step S5, and selects the optimum dot record mode based on the
calculated evaluation value at step S6. The procedure subsequently
stores the selected dot record mode into the mode selection memory
220 included in the PROM 42 (see FIGS. 2 and 4) at step S7. In the
example of FIG. 4, only the "720 dpi, Fine" mode has a plurality of
dot record modes as selectable options. When there are a plurality
of mode classes, each having a plurality of dot record modes as
selectable options, the procedures of steps S4 through S7 are
repeatedly executed to select one optimum dot record mode with
regard to each mode class. The information representing the
selected dot record modes is collectively stored as the print mode
selection information in the mode selection memory 220. The
procedures of the respective steps are discussed in detail
below.
[0100] FIG. 11 is a flowchart showing the details of the process of
generating the first displacement data at step S1 in the flowchart
of FIG. 10. The procedure of step S1 attaches the manufactured
print head 28 to a predetermined test scan drive unit (not shown).
When the program enters the routine of FIG. 11, a head-induced
displacement detection pattern recording unit 324 (see FIG. 12)
first causes the print head 28 to eject ink droplets while being
fed in the direction of the main scan, so as to print ruled lines
in the feeding direction at step S11. The ruled lines recorded here
form a head-induced displacement detection pattern.
[0101] FIG. 12 shows an example of the head-induced displacement
detection pattern recorded at step S11 and a process of reading the
head-induced displacement detection pattern. The print head 28
attached to the scan drive unit included in the printing apparatus
is fed in the direction perpendicular to the alignment of the
nozzle array (see FIG. 3) in the respective passes of main scan.
The print head 28 is fed in the direction identical with the main
scanning direction, that is, the direction perpendicular to the
alignment of the nozzle array, in the process of recording the
head-induced displacement detection pattern. The head-induced
displacement detection pattern recording unit 324, which controls
the print head 28 to record the ruled lines, is actualized by
execution of a predetermined computer program by a computer 390,
which is part of the equipment for manufacturing printers.
[0102] The upper portion of FIG. 12 shows an example of horizontal
ruled lines recorded with all the nozzles included in one nozzle
array for one color ink. The numeral with the symbol # above each
ruled line represents the nozzle used to record the ruled line. In
this example, it is assumed that the nozzle array includes 8
nozzles #0 through #7. The nozzles of even ordinal numbers record
ruled lines on the left half of the printing paper, whereas the
nozzles of odd ordinal numbers record ruled lines on the right half
of the printing paper. If the ruled lines are recorded with
adjoining nozzles in an identical horizontal range on the printing
paper, the adjoining ruled lines are close to each other and are
not readily distinguishable from each other. The horizontal range
in which the respective ruled lines are recorded may be divided
into three sections, instead of the two sections. The ruled line on
the lower most end (the ruled line recorded with the nozzle #7) is
a common ruled line CR. The common ruled line CR is used as the
reference line for evaluation of the displacement of the other
ruled lines. The nozzle recording this common ruled line CR is the
reference nozzle. These ruled lines are recorded simultaneously by
one pass in the main scanning direction. The interval between the
adjoining ruled lines is thus equal to the nozzle pitch k [dots] on
the design. The lower portion of FIG. 12 shows an image sensor 320,
a first displacement data generation unit 322, and the head-induced
displacement detection pattern recording unit 324, which are used
for the series of processing shown in the flowchart of FIG. 11. The
first displacement data generation unit 322 is actualized by
execution of a predetermined computer program by the computer
390.
[0103] Referring back to the flowchart of FIG. 11, the procedure
actuates the image sensor 320 (see FIG. 12) to read the center
positions of the respective ruled lines at step S12. A linear image
sensor of CCDs or a two-dimensional image sensor may be applied for
the image sensor 320.
[0104] In accordance with a concrete procedure of step S12, the
first displacement data generation unit 322 causes each ruled line
read by the image sensor 320 to be subjected to the core line
process to determine the center position of the ruled line. The
center position of each ruled line is measured as a distance DIS
from the common ruled line CR. In the example of FIG. 12, the
center positions of the ruled lines recorded with the nozzles #0
and #1 are respectively obtained as distances DISO.sub.0-7 and
DIS.sub.1-7 from the common ruled line CR.
[0105] At step S13 in the flowchart of FIG. 11, the first
displacement data generation unit 322 calculates deviations of the
center positions DH on the respective ruled lines recorded with the
corresponding nozzles. Each of center position deviations DH.sub.0
to DH.sub.6 on the respective ruled lines represents the difference
between the center position DIS measured by the image sensor 320
and a designed center position. For example, the interval between
the nozzles #6 and #7 is equal to the nozzle pitch k [dots] on the
design. The designed center position on the ruled line recorded
with the nozzle #6 is thus equal to k [dots], whereas the observed
center position is DIS.sub.6-7. The center position deviation
DH.sub.6 with regard to the nozzle #6 is obtained by the equation
given below:
DH.sub.6=DIS.sub.6-7-k.multidot.w
[0106] where w denotes the dot pitch [inch].
[0107] The center position deviation DH.sub.5 with regard to the
nozzle #5 is the difference between the observed center position
DIS.sub.5-7 and 2.multidot.k [dots]. The center position deviation
DH.sub.4 with regard to the nozzle #4 is the difference between the
observed center position DIS.sub.4-7 and 3.multidot.k [dots]. The
center position deviations with regard to the other nozzles are
defined in the same manner. In general, the center position
deviation DH.sub.n on the ruled line recorded with the nozzle #n
(n=0 to 6) is written as Equation (1) given below:
DH.sub.n=DIS.sub.n.multidot.N-(N-n).multidot.k.multidot.w (1)
[0108] where N denotes the number of nozzles included in each
nozzle array.
[0109] Each of the center position deviations DH.sub.0 to DH.sub.6
has a positive value when the ruled line is farther from the common
ruled line CR than the designed value, while having a negative
value when the ruled line is closer to the common ruled lines CR
than the designed value. The nozzle #7 is the reference nozzle, so
that the center position deviation is not defined with regard to
the nozzle #7.
[0110] The center position deviations DH.sub.0 to DH.sub.6 are
regarded as the deviations of dot recording position intrinsic to
the respective nozzles #0 through #6. At step S14 in the flowchart
of FIG. 11, the first displacement data generation unit 322 stores
the center position deviations DH.sub.0 to DH.sub.6 intrinsic to
the respective nozzles #0 through #6 as the first displacement data
into a head ID memory 202, which is provided on the print head 28.
The head ID memory 202 corresponds to the first storage unit of the
present invention.
[0111] FIG. 13 is a flowchart showing the details of the process of
generating the second displacement data at step S2 in the flowchart
of FIG. 10. The procedure of step S2 attaches a predetermined test
head 426 (see FIG. 14) to the manufactured scan drive unit. The
test head 426 has only one nozzle, from which ink is ejected. When
the program enters the routine of FIG. 13, a sub-scan-induced
displacement detection pattern recording unit 424 (see FIG. 14)
causes a sub-scan-induced displacement detection pattern to be
printed on a sheet of printing paper set on the scan drive unit at
step S21. In accordance with a concrete procedure of step S21, the
sub-scan-induced displacement detection pattern recording unit 424
causes the scan drive unit to carry out the main scan and the
sub-scan in each dot record mode, while causing one nozzle on the
test head 426 to eject ink and print ruled lines (the
sub-scan-induced displacement detection pattern). The
sub-scan-induced displacement detection pattern recording unit 424
is actualized by execution of a predetermined computer program by a
computer 490 (see FIG. 14), which is part of the equipment for
manufacturing printers.
[0112] FIG. 14 shows an example of the sub-scan-induced
displacement detection pattern recorded at step S21 and a process
of reading the sub-scan-induced displacement detection pattern. In
the example of FIG. 14, the sub-scan-induced displacement detection
pattern including 5 ruled lines is recorded by the combined
functions of the test head 426 and the sub-scan-induced
displacement detection pattern recording unit 424. The
sub-scan-induced displacement detection pattern recording unit 424
carries out the sub-scan by one cycle of the feeding amounts of
sub-scan set in each dot record mode, while printing the
sub-scan-induced displacement detection pattern in the main scan.
In the first dot recording mode shown in FIG. 5, for example, the
ruled lines are printed in the main scan, while the sub-scan is
carried out between each adjoining passes of the main scan with a
variation in feeding amount as 10 dots, 7 dots, 6 dots, and 9 dots.
This gives the total of five ruled lines including a ruled line
recorded prior to the sub-scan. This ruled line recorded prior to
the sub-scan is hereinafter referred to as a reference ruled line
CR2. These five ruled lines form the sub-scan-induced displacement
detection pattern.
[0113] The lower portion of FIG. 14 shows a linear image sensor 420
and a second displacement data generation unit 422, which are also
used for the series of processing in the flowchart of FIG. 13. The
second displacement data generation unit 422 is actualized by
execution of a predetermined computer program by the computer 490,
which is part of the equipment for manufacturing printers. A linear
image sensor of CCDs or a two-dimensional image sensor may be
applied for the image sensor 420. The procedure actuates the image
sensor 420 to read the center positions of the respective ruled
lines at step S22 in the flowchart of FIG. 13. The procedure of
reading the center positions of the respective ruled lines at step
S22 is identical with the procedure of step S12 in the flowchart of
FIG. 11. The center position of each ruled line is observed as a
distance DRD from the reference ruled line CR2 printed prior to the
sub-scan. In the example of FIG. 14, the center positions of the
respective ruled lines are sequentially obtained as DRD.sub.1 to
DRD.sub.4.
[0114] At step S23 in the flowchart of FIG. 13, the second
displacement data generation unit 422 calculates inter-ruled line
distances DSD from the observed center positions DRD of the
respective ruled lines (that is, the distances from the reference
ruled lines CR2) and deviations DSS of the inter-ruled line
distances. The inter-ruled line distance represents the distance
between two adjoining ruled lines among the ruled lines printed at
step S21. The procedure of step S21 carries out the sub-scan by a
predetermined feeding amount or distance between recording of one
ruled line and recording of a next ruled line. The inter-ruled line
distance DSD accordingly corresponds to each feeding distance of
sub-scan between the adjoining ruled lines. In the example of FIG.
14, an inter-ruled line distance DSD.sub.10 between the reference
ruled line CR2 and the second ruled line is obtained by the
equation given below. Here the feeding amount of sub-scan is equal
to 10 [dots] between printing of the reference ruled line CR2 and
printing of the second ruled line, so that the inter-ruled line
distance between the reference ruled line CR2 and the second ruled
line is expressed as DSD.sub.10.
DSD.sub.10=DRD.sub.1
[0115] In the example of FIG. 14, an inter-ruled line distance
DSD.sub.7 between the second ruled line and the third ruled line
recorded via the sub-scan feed of 7 dots is obtained by the
equation given below:
DSD.sub.7=DRD.sub.2-DRD.sub.1
[0116] Other inter-ruled line distances DSD.sub.6 and DSD.sub.9 are
obtained in a similar manner as:
DSD.sub.6=DRD.sub.3-DRD.sub.2
DSD.sub.9=DRD.sub.4-DRD.sub.3
[0117] Deviations DSS.sub.10, DSS.sub.7, DSS.sub.6, and DSS.sub.9
of the inter-ruled line distances respectively represent the
differences between the inter-ruled line distances DSD.sub.10,
DSD.sub.7, DSD.sub.6, and DSD.sub.9, which are calculated from the
center positions DRD.sub.1 through DRD.sub.4 of the respective
ruled lines measured by the image sensor 420, and designed feeding
amounts of sub-scan. For example, the sub-scan feed of 10 dots is
carried out between printing of the reference ruled line CR2 and
printing of the second ruled line, so that the designed inter-ruled
line distance is equal to 10 [dots]. The deviation DSS.sub.10 of
the inter-ruled line distance under the sub-scan feed of 10 dots is
difference between the calculated inter-ruled line distance
DSD.sub.10 and the designed feeding amount 10 [dots]. The deviation
DSS.sub.10 is expressed by the equation given below:
DSS.sub.10=DSD.sub.10-10.multidot.w
[0118] where w denotes the dot pitch [inch].
[0119] The other deviations DSS.sub.7, DSS.sub.6, and DSS.sub.9 of
the inter-ruled line distances are obtained in a similar manner
as:
DSS.sub.7=DSD.sub.7-7.multidot.w
DSS.sub.6=DSD.sub.6-6.multidot.w
DSS.sub.9=DSD.sub.9-9.multidot.w
[0120] The deviations DSS.sub.10, DSS.sub.7, DSS.sub.6, and
DSS.sub.9 of the inter-ruled line distances respectively correspond
to the errors of sub-scan feed by the feeding amounts of 10 dots, 7
dots, 6 dots, and 9 dots. Each of the deviations DSS.sub.10,
DSS.sub.7, DSS.sub.6, and DSS.sub.9 of the inter-ruled line
distances has a positive value when the actual feeding amount of
sub-scan is greater than the designed feeding amount, while having
a negative value when the actual feeding amount of sub-scan is
smaller than the designed feeding amount.
[0121] At step S23 in the flowchart of FIG. 13, the second
displacement data generation unit 422 calculates the inter-ruled
line distances DSD from the observed center positions DRD of the
respective ruled lines (that is, the distances from the reference
ruled line CR2) and subsequently determines the errors of sub-scan
feed DSS. The second displacement data generation unit 422
subsequently stores the calculated errors of sub-scan feed
DSS.sub.10, DSS.sub.7, DSS.sub.6, and DSS.sub.9 as the second
displacement data in a sub-scan displacement memory 222 included in
the PROM 42 at step S24. The sub-scan displacement memory 222
corresponds to the second storage unit of the present
invention.
[0122] Referring back to the flowchart of FIG. 10, the print head
28 with the first displacement data stored in the head ID memory
202 is attached to the scan drive unit with the second displacement
data stored in the sub-scan displacement memory 222.
[0123] In the actual printing operations, the dot record mode
unequivocally determines how each raster line is recorded on the
printing paper, that is, which nozzle is used to record the raster
line and what settings of the sub-scan feed are applied prior to
recording the raster line. In other words, the nozzle used and the
settings of the sub-scan feed to record each raster line on the
printing paper are varied according to the selected dot record
mode. For example, in the first dot recording mode shown in FIGS. 6
and 7, the 10.sup.th raster line is recorded with the nozzle #3
after two sub-scan feeds by the feeding amounts of 10 dots and 7
dots. In the second dot recording mode shown in FIGS. 8 and 9, on
the other hand, the 10.sup.th raster line is recorded with the
nozzle #7 prior to any pass of the sub-scan. The displacement of
dot recording position in the sub-scanning direction on each raster
line is the sum of the accumulated errors of sub-scan feed and the
deviation of the dot recording position intrinsic to each nozzle
(the vertical displacement). The displacements of dot recording
position on the respective raster lines are thus calculated from
the first displacement data (that is, the deviations of dot
recording position intrinsic to the respective nozzles) DH.sub.0
through DH.sub.6 and the second displacement data (that is, the
errors of sub-scan feed) DSS.sub.10, DSS.sub.7, DSS.sub.6, and
DSS.sub.9.
[0124] For example, in the first dot recording mode shown in FIG.
7, the 10.sup.th raster line is recorded with the nozzle #3 after
the first pass of sub-scan by 10 dots and the second pass of
sub-scan by 7 dots. The displacement of dot recording position
D.sub.1,10 on the 10.sup.th raster line in the first recording
process is expressed by the equation given below. In distinction
from the errors of the respective sub-scan feeds in the second dot
recording mode, the errors of the respective sub-scan feeds by 10,
7, 6, and 9 dots in the first dot recording mode are expressed as
DSS.sub.1,10, DSS.sub.1,7, DSS.sub.1,6 and DSS.sub.1,9.
D.sub.1,10=(DSS.sub.1,10+DSS.sub.1,7)-DH.sub.3
[0125] In the first dot recording mode, the 20.sup.th raster line
is recorded with the nozzle #4 after the first pass of sub-scan by
10 dots, the second pass of sub-scan by 7 dots, and the third pass
of sub-scan by 6 dots. The displacement of dot recording position
D.sub.1,20 on the 20.sup.th raster line in the first recording
process is accordingly expressed by the equation given below:
D.sub.1,20=(DSS.sub.1,10+DSS.sub.1,7+DSS.sub.1,6)-DH.sub.4
[0126] In general, when the p-.sup.th raster line in the first dot
record mode is recorded with the r-.sup.th nozzle, the displacement
of dot recording position D.sub.1,p in the sub-scanning direction
on the p-.sup.th raster line is expressed by the equation given
below:
D.sub.1,p=.SIGMA..sub.1,p(DSS)-DH.sub.r
[0127] Here the first term on the right side .SIGMA..sub.1,p(DSS)
represents the summation of the errors of the respective sub-scan
feeds DSS in the first dot record mode before the p-.sup.th raster
line is recorded. The second term on the right side DH.sub.r
represents the deviation of the dot recording position by the
r-.sup.th nozzle, which records the p-.sup.th raster line, from the
dot recording position by the reference nozzle. The dot recording
position may be shifted downstream or upstream in the sub-scanning
direction. The displacement of dot recording position D.sub.1,p has
a positive value in the downstream shift, while having a negative
value in the upstream shift. The print head 28 is attached to the
printer 22 in such a manner that the nozzle #1 is present on the
upstream side in the sub-scanning direction and the reference
nozzle #7 is present on the downstream side. As discussed
previously with regard to step S13 in the flowchart of FIG. 11,
DH.sub.r has a positive value when the position of the ruled line
recorded with each nozzle is deviated relative to the position of
the common ruled line CR recorded with the reference nozzle #7
toward the nozzle #1 (that is, to the upstream side in the
sub-scanning direction). In the upper equation, the negative sign
is accordingly given to the second term on the right side
DH.sub.r.
[0128] The displacement of dot recording position D.sub.i,p on the
p-.sup.th raster line thus obtained represents the difference from
a designed dot recording position relative to the raster line
recorded with the reference nozzle #7 prior to any pass of the
sub-scan. The 9.sup.th raster line shown in FIG. 7 is recorded with
the reference nozzle #7 prior to any pass of the sub-scan, so that
the displacement of dot recording position D.sub.1,9 on the
9.sup.th raster line is equal to zero.
[0129] The above description with regard to the displacement of dot
recording position on the raster line is also applicable to the
second dot record mode. In general, when the p-.sup.th raster line
in the i-.sup.th dot record mode is recorded with the r-.sup.th
nozzle, the displacement of dot recording position D.sub.i,p in the
sub-scanning direction on the p-.sup.th raster line is expressed by
Equation (2) given below:
D.sub.i,p=.SIGMA..sub.i,p(DSS)-DH.sub.r (2)
[0130] Here the first term on the right side .SIGMA..sub.i,p(DSS)
represents the summation of the errors of the respective sub-scan
feeds DSS in the i-.sup.th dot record mode before the p-.sup.th
raster line is recorded. The second term on the right side DH.sub.r
represents the deviation of the dot recording position by the
r-.sup.th nozzle, which records the p-.sup.th raster line, from the
dot recording position by the reference nozzle.
[0131] FIG. 15 shows the relations among a displacement calculation
unit 502 included in a computer 590, which is part of the equipment
for manufacturing printers, the head ID memory 202 on the print
head 28, and the sub-scan displacement memory 222 included in the
scan drive unit. Although the print head 28 is incorporated in the
printer 22, the print head 28 is separate from the printer 22 in
the illustration of FIG. 15 for convenience. Referring back to the
flowchart of FIG. 10, at step S4, the displacement calculation unit
502 included in a mode specification unit 522 calculates the
displacement of dot recording position D.sub.i,p on each raster
line according to the above procedures, based on the first
displacement data DH.sub.i,p stored in the head ID memory 202 and
the second displacement data DSS stored in the sub-scan
displacement memory 222. The displacement of dot recording position
Dip on each raster line is calculated with regard to each of the
dot record modes provided as selectable options. Here the mode
specification unit 522 corresponds to the selection unit of the
present invention.
[0132] At step S5 in the flowchart of FIG. 10, the mode
specification unit 522 determines a difference in dot array
interval ID.sub.i(p+1)-p between adjoining raster lines in each dot
record mode and calculates a variance DDi of the difference in dot
array interval ID.sub.i(p+1)-p. The variance DDi of the difference
in dot array interval ID.sub.i(p+1)-p represents the evaluation
value in each dot record mode.
[0133] The displacement of dot recording position D.sub.i,p on the
p-.sup.th raster line and the displacement of dot recording
position D.sub.i(p+1) on the (p+1)-.sup.th raster line are obtained
according to Equation (2) given above. The difference in dot array
interval ID.sub.i(p+1)-p between the dot array on the p-.sup.th
raster line and the dot array on the (p+1)-.sup.th raster line is
expressed by Equation (3) given below. In Equation (3), when the
interval between the dot array on the p-.sup.th raster line and the
dot array on the (p+1)-.sup.th raster line is greater than a
designed value, the difference in dot array interval
ID.sub.i,(p+1)-p has a positive value. When the interval is less
than the designed value, on the other hand, the difference
ID.sub.i,(p+1)-p has a negative value.
ID.sub.i,(p+1)-p=D.sub.i(p+1)-D.sub.i,p (3)
[0134] After calculating the evaluation value DDi in each dot
record mode at step S5, the mode specification unit 522 selects the
dot record mode having the smallest evaluation value DDi at step S6
in the flowchart of FIG. 10.
[0135] Since a smaller variation in dot array interval between each
pair of adjoining raster lines is desirable, the procedure selects
the dot record mode having the smallest variance DDi of the
difference in dot array interval ID.sub.i,(p+1)-p. When the dot
array interval between adjoining raster lines is not constant in
the sub-scanning direction but is varied to be greater and less
than the designed value, streaks or stripes extending in the main
scanning direction may appear in the resulting printed image. Such
phenomenon is called "banding". The difference in dot array
interval ID.sub.i,(p+1)-p between adjoining raster lines in each
dot record mode may have a positive value or a negative value
corresponding to the greater dot array interval or the smaller dot
array interval than the designed value. If each dot record mode is
evaluated by the arithmetic mean of the difference in dot array
interval ID.sub.i,(p+1)-p it is practically impossible to
distinguish the dot record mode actually having a small variation
in dot array interval from the dot record mode having similar rates
of the greater dot array interval and the smaller dot array
interval than the designed value, which cancel each other.
Selection of the latter dot record mode may cause banding in the
resulting printed image. The method of evaluating each dot record
mode by the variance DDi of the difference in dot array interval
ID.sub.i,(p+1)-p between adjoining raster lines, however, does not
cause such problems but enables selection of the desired dot record
mode that ensures the good picture quality of the printing
results.
[0136] Referring back to the flowchart of FIG. 10 after selecting
the desired dot record mode at step S6, the mode specification unit
522 stores the number allocated to the selected dot record mode
into the mode selection memory 220 included in the PROM 42 at step
S7. The mode specification unit 522 and the displacement
calculation unit 502 are actualized by execution of predetermined
computer programs by the computer 590, which is part of the
equipment for manufacturing printers.
[0137] In the actual printing process, the record mode setting unit
204 in the printer 22 (see FIG. 4) receives information
representing the printing resolution and the mode class from the
header of print data. The record mode setting unit 204 reads the
print mode selection information corresponding to the printing
resolution and the mode class from the mode selection memory 220 in
the PROM 42, and subsequently reads the dot record mode information
corresponding to the print mode selection information from the
record mode table 206. The record mode setting unit 204 then gives
the parameters defining the main scan and sub-scan operations to
the drive unit controller 208 and the raster data storage unit 216.
The drive unit controller 208 controls the main scan drive unit
210, the sub-scan drive unit 212, and the print head drive unit 214
to carry out an actual printing operation.
[0138] D. Another Method of Setting Displacement Data
[0139] The procedure of the above embodiment determines the
displacement of dot recording position D.sub.i,p on each raster
line in each dot record mode, calculates the difference in dot
array interval ID.sub.i,(p+1)-p between adjoining raster lines, and
selects the dot record mode having the smallest variance DDi of the
difference in dot array interval ID.sub.i,(p+1)-p. The desired dot
record mode may, however, be selected according to other criterion.
The following describes another procedure that calculates the dot
array interval between adjoining raster lines from the measured dot
recording positions and the feeding amounts of sub-scan and
evaluates each dot record mode based on the variance of the
calculated dot array interval.
[0140] FIG. 16 is a flowchart showing another procedure of
manufacturing the printing apparatus. The procedure of FIG. 16 is
similar to the procedure shown in the flowchart of FIG. 10, except
that the processes of steps S1a, S2a, S4a, S5a, and S6a are
different from those of steps S1, S2, S4, S5, and S6 in FIG. 10.
The following mainly describes the different parts from the
procedure of FIG. 10.
[0141] FIG. 17 is a flowchart showing the details of the process of
generating the first displacement data at step Slain the flowchart
of FIG. 16. The procedure of FIG. 17 does not have a step
corresponding to step S13 in the flowchart of FIG. 11 and includes
step S14a that is different from step S14. Otherwise the process of
FIG. 17 is similar to the process of FIG. 11. In the procedure of
FIG. 17 that generates the first displacement data, after the
center positions DIS.sub.0-7 to DIS.sub.6-7 of the respective ruled
lines (see FIG. 12) are read at step S12, the first displacement
data generation unit 322 stores the obtained center positions
DIS.sub.0-7 to DIS.sub.6-7 of the respective ruled lines as the
first displacement data into the head ID memory 202 at step S14a.
The center positions DIS.sub.0-7 to DIS.sub.6-7 of the respective
ruled lines read at step S12 include the deviations of the dot
recording positions intrinsic to the respective nozzles. The first
displacement data thus substantially represents the deviations of
dot recording position in the sub-scanning direction intrinsic to
the respective nozzles.
[0142] FIG. 18 is a flowchart showing the details of the process of
generating the second displacement data at step S2a in the
flowchart of FIG. 16. The process of FIG. 18 is similar to the
process shown in the flowchart of FIG. 13, except that steps S23a
and S24a are different from steps S23 and S24 in FIG. 13. In the
procedure of FIG. 18, after the center positions DRD.sub.1 to
DRD.sub.4 of the respective ruled lines (see FIG. 14) are read at
step S22, the second displacement data generation unit 422
calculates the inter-ruled line distances DSD.sub.10, DSD.sub.7,
DSD.sub.6, and DSD.sub.9 from the obtained center positions
DRD.sub.1 to DRD.sub.4 of the respective ruled lines at step S23a.
As discussed previously, the inter-ruled line distances DSD.sub.10,
DSD.sub.7, DSD.sub.6, and DSD.sub.9 represent the actual feeding
distances of sub-scan. The second displacement data generation unit
422 subsequently stores the calculated inter-ruled line distances
(that is, the feeding distances of sub-scan) DSD.sub.10, DSD.sub.7,
DSD.sub.6, and DSD.sub.9 as the second displacement data into the
sub-scan displacement memory 222 at step S24a.
[0143] As discussed previously with regard to step S21, DRD.sub.1
to DRD.sub.4 represent the center positions of the respective ruled
lines actually recorded with the sub-scan feeds (that is, the
distances from the reference ruled line CR2), and thus include
errors of sub-scan feed. The inter-ruled line distances (the
feeding distances of sub-scan) DSD.sub.10, DSD.sub.7, DSD.sub.6,
and DSD.sub.9 calculated from DRD.sub.1 to DRD.sub.4 also include
the errors of sub-scan feed. The second displacement data thus
substantially represents the errors of sub-scan feed.
[0144] Referring back to the flowchart of FIG. 16, at step S4a, the
displacement calculation unit 502 calculates the recording
positions of the dot arrays on the respective raster lines in the
sub-scanning direction in each dot record mode, based on the first
displacement data DIS.sub.0-7 to DIS.sub.6-7 and the second
displacement data DSD.sub.10, DSD.sub.7, DSD.sub.6, and DSD.sub.9.
The first displacement data DIS.sub.0-7 to DIS.sub.6-7 represent
the positions of the dot arrays recorded with the respective
nozzles relative to the position of the dot array recorded with the
reference nozzle #7. The second displacement data DSD.sub.10,
DSD.sub.7, DSD.sub.6, and DSD.sub.9 represent the feeding amounts
of sub-scan. In the example of FIG. 7, the 2.sup.nd raster line is
recorded with the nozzle #1 after the first pass of sub-scan by 10
dots and the second pass of sub-scan by 7 dots, so that the
recording position SSR.sub.1,2 of the dot array on the 2.sup.nd
raster line is expressed by the equation given below:
SSR.sub.1,2=(DSD.sub.10+DSD.sub.7)-DIS.sub.1-7
[0145] In general, when the p-.sup.th raster line in the first dot
record mode is recorded with the r-.sup.th nozzle, the recording
position SSR.sub.1,p of the dot array on the pith raster line in
the sub-scanning direction is expressed by the equation given
below:
SSR.sub.1,p=.SIGMA..sub.1,p(DSD)-DIS.sub.r-N0
[0146] Here the first term on the right side .SIGMA..sub.1,p(DSD)
represents the summation of the feeding amounts of sub-scan DSD in
the first dot record mode before the p-.sup.th raster line is
recorded. The second term on the right side DIS.sub.r-N0 represents
the center position of the p-.sup.th raster line recorded with the
r-.sup.th nozzle relative to the center position of a reference
raster line recorded with a reference nozzle #N0. The recording
position SSR.sub.1,p of the dot array on the p-.sup.th raster line
has a positive value in the downstream direction of sub-scan feed.
The print head 28 is attached to the printer 22 in such a manner
that the nozzle #1 is present on the upstream side in the
sub-scanning direction and the reference nozzle #7 is present on
the downstream side. As discussed previously with regard to FIG.
12, DIS.sub.r-N0 represents a distance between the ruled line
recorded with each nozzle and the common ruled line CR. Namely
DIS.sub.r-N0 shows the observed center position of each ruled line
recorded with each nozzle relative to the center position of the
common ruled line CR recorded with the reference nozzle #N0 (#7 in
the example of FIG. 12), which is located on the most downstream
side in the sub-scanning direction. In the upper equation, the
negative sign is accordingly given to the second term on the right
side DIS.sub.r-N0.
[0147] The above description with regard to the dot recording
position on the raster line is also applicable to the second dot
record mode. In general, the recording position SSR.sub.i,p of the
dot array on the p-.sup.th raster line in the sub-scanning
direction in the i-.sup.th dot record mode is expressed by Equation
(4) given below:
SSR.sub.i,p=.SIGMA..sub.i,p(DSD.sub.i)-DIS.sub.r-N0 (4)
[0148] Here the first term on the right side
.SIGMA..sub.i,p(DSD.sub.i) represents the summation of the feeding
amounts of sub-scan DSD in the i-.sup.th dot record mode before the
p-.sup.th raster line is recorded. The second term on the right
side DIS.sub.r-N0 represents the center position of the p-.sup.th
raster line recorded with the r-.sup.th nozzle relative to the
center position of the reference raster line recorded with the
reference nozzle #N0 in the i-.sup.th dot record mode. At step S4a
in the flowchart of FIG. 16, the displacement calculation unit 502
calculates the recording position SSR.sub.i,p of the dot array on
each raster line in the sub-scanning direction according to
Equation (4) given above. When there are a plurality of mode
classes, each having a plurality of dot record modes as selectable
options (see FIG. 4), the procedures of steps S4a through S7 are
repeatedly executed to select one optimum dot record mode with
regard to each mode class as in the case of the above
embodiment.
[0149] FIG. 19 is a flowchart showing the details of the process of
calculating the evaluation value with regard to each dot record
mode at step S5a in the flowchart of FIG. 16. FIG. 20 shows the
principle of calculating the dot array interval between adjoining
raster lines as the evaluation value. In the example of FIG. 20,
the dot array recorded on each raster line is shown as the ruled
line. Dot arrays of ten raster lines, that is, (p-5)-.sup.th to
(p+4)-.sup.th raster lines, are shown in FIG. 20. At step S5a, the
displacement calculation unit 502 calculates the evaluation value
with regard to each dot record mode based on the recording
positions of the dot arrays according to the procedures discussed
below. When the program enters the routine of FIG. 19, the
displacement calculation unit 502 first specifies raster groups of
plural consecutive raster lines with regard to all the raster lines
on the printing paper at step S31. For example, as shown in FIG.
20, each raster group may include six consecutive raster lines. The
respective raster groups are specified by sequentially shifting the
included raster lines by one.
[0150] The displacement calculation unit 502 subsequently
calculates the mean dot array interval between adjoining raster
lines included in each raster group at step S32. The dot array
interval Dras.sub.i,q-p between the p-th raster line and the
q-.sup.th raster line in the i-.sup.th dot record mode is expressed
by Equation (5) given below. Here q>p.
Dras.sub.i,q-p=SSR.sub.i,q-SSR.sub.i,p (5)
[0151] In the example of FIG. 20, a j-.sup.th raster group includes
(p-3)-.sup.th through (p+2)-.sup.th raster lines. The mean dot
array interval MDras.sub.i,j in the j-.sup.th raster group is
obtained by dividing the dot array interval Dras.sub.i,(p+2)-(p-3)
between both the end raster lines, that is, the (p-3)-.sup.th
raster line and the (p+2)-.sup.th raster line, by the number of
intervals 5. The dot array interval Dras.sub.i,q-p is calculated
according to Equation (5) given above. The mean dot array interval
MDras.sub.i,j in the j-.sup.th raster group is accordingly
expressed as Equation (6) given below:
MDras.sub.i,j=(SSR.sub.i,p+2-SSR.sub.i,p-3)/5 (6)
[0152] When M denotes the aggregate number of raster lines included
in each raster group and p0 denotes the number of the first raster
line included in the j-.sup.th raster group (p-3 in Equation (6)),
Equation (6) is rewritten as:
MDras.sub.i,j=(SSR.sub.i,p0+M-1-SSR.sub.i,p0)/(M-1) (7)
[0153] The mode specification unit 522 calculates the mean dot
array interval MDras.sub.i,j in each raster group according to
Equation (7) given above at step S32 in the flowchart of FIG.
19.
[0154] At subsequent step S33, the mode specification unit 522
calculates a difference min-max(MDras.sub.i,j) between the largest
and the smallest mean dot array intervals MDras.sub.i,j of the
raster groups in each dot record mode. The difference
min-max(MDras.sub.i,j) is specified as the evaluation value
regarding the inter-ruled line distance in each dot record mode.
Referring back to the flowchart of FIG. 16, at step S5a, the
displacement calculation unit 502 calculates the evaluation value
min-max(MDras.sub.i,j) in each record mode according to the above
procedures.
[0155] At subsequent step S6a, the dot record mode having the
smallest evaluation value min-max(MDras.sub.i,j) is selected. The
banding occurs due to the variation in dot array interval between
adjoining raster lines relative to the designed value. The method
adopted here calculates the mean dot array interval in each raster
group and selects the dot record mode having the smallest
difference between the maximum mean dot array interval and the
minimum mean dot array interval, that is, the dot record mode
having little variation in dot array interval among different
raster groups. This arrangement enables selection of the desired
dot record mode having little chance of causing the banding.
[0156] In both the case of directly evaluating the displacement
like the example of FIG. 10 and the case of evaluating the
displacement based on the dot array interval like the example of
FIG. 16, the evaluation value may be the difference between the
maximum value and the minimum value, the variance, the standard
deviation, or any of other appropriate values.
[0157] E. Other Modifications
[0158] (1) Application of Determining Dot Record Mode After
Attachment of Print Head to Scan Drive Unit
[0159] FIG. 21 is a flowchart showing a procedure of determining
the dot record mode after attachment of the print head to the scan
drive unit. FIG. 22 is a block diagram showing the structure of a
printer driver 96a that includes a mode specification unit 632 as a
functional unit thereof. In the embodiment discussed above, the
setting of the first displacement data (see FIG. 11), the setting
of the second displacement data (see FIG. 13), and the selection of
the dot record mode (see FIG. 10) are carried out in the course of
manufacturing the printer. Any of these processes may alternatively
be carried out after the attachment of the print head to the scan
drive unit. For example, the selection of the dot record mode may
be performed after the attachment of the print head to the scan
drive unit according to the procedures discussed below. The
procedure stores the first displacement data into the head ID
memory 202 and the second displacement data into the sub-scan
displacement memory 222 provided in the PROM 42 in the course of
manufacturing the printer like the procedure of FIG. 10. The mode
specification unit 632 included in the printer driver 96a has the
equivalent functions to those of the mode specification unit 522
shown in FIG. 15. The other constituents of the printing apparatus
are similar to those of the printing apparatus of the embodiment
discussed above. The functional units in the printer driver 96a
that are the same as the functional units in the printer driver 96
shown in FIG. 1 are omitted from the illustration of FIG. 22. When
the program enters the routine of FIG. 21, the mode specification
unit 632 first reads the first displacement data from the head ID
memory 202 at step S41, and reads the second displacement data from
the sub-scan displacement memory 222 at step S42. S42 may be
carried out prior to S41. A displacement calculation unit 602,
which corresponds to the displacement calculation unit 502 shown in
FIG. 15, calculates the displacement of dot recording position on
each raster line in each dot record mode at step S43. The mode
specification unit 632 calculates the evaluation value in each dot
record mode from the calculated displacement on the raster line at
step S44, and selects the optimum dot record mode with regard to
each mode class at step S45. After the above series of the
processing, the drive unit controller 208 (see FIG. 4) controls the
related units to implement printing at step S46. In the printing
apparatus with a replaceable print head, this arrangement enables
the desired dot record mode to be newly set in the printer after
every replacement of the print head.
[0160] (2) Application of Generating First Displacement Data After
Attachment of Print Head to Scan Drive Unit
[0161] FIG. 23 is a block diagram showing the structure of a
printer driver 96b that includes a first displacement data
generation unit 622 and a head-induced displacement detection
pattern recording unit 624 as functional units thereof. The setting
of the first displacement data shown in the flowchart of FIG. 11
may be carried out after the assembly of the printer. In this
application, the first displacement data generation unit 622 and
the head-induced displacement detection pattern recording unit 624
included in the printer driver 96b respectively have equivalent
functions to those of the first displacement data generation unit
322 and the head-induced displacement detection pattern recording
unit 324 shown in FIG. 12. These functional units execute the
series of processing according to the procedures shown in the
flowchart of FIG. 11. The functional units in the printer driver
96b that are the same as the functional units in the printer driver
96 shown in FIG. 1 are omitted from the illustration of FIG. 23.
The general flow in this application replaces the contents of step
S41 in the flowchart of FIG. 21 with "the process of generating the
first displacement data". In the process of printing the ruled
lines (the head-induced displacement detection pattern) at step S11
in the flowchart of FIG. 11, the head-induced displacement
detection pattern recording unit 624 carries out only the main scan
without the sub-scan to record dots and print the ruled lines. This
application does not require the first displacement data to be
stored in the print head 28 in advance.
[0162] (3) Application of Generating Second Displacement Data After
Attachment of Print Head to Scan Drive Unit
[0163] FIG. 24 is a block diagram showing the structure of a
printer driver 96c that includes a second displacement data
generation unit 626 and a sub-scan-induced displacement detection
pattern recording unit 628 as functional units thereof The setting
of the second displacement data shown in the flowchart of FIG. 13
may be carried out after the assembly of the printer. In this
application, the second displacement data generation unit 626 and
the sub-scan-induced displacement detection pattern recording unit
628 included in the printer driver 96c respectively have equivalent
functions to those of the second displacement data generation unit
422 and the sub-scan-induced displacement detection pattern
recording unit 424 shown in FIG. 14. These functional units execute
the series of processing according to the procedures shown in the
flowchart of FIG. 13. The functional units in the printer driver
96c that are the same as the functional units in the printer driver
96 shown in FIG. 1 are omitted from the illustration of FIG. 24.
The general flow in this application replaces the contents of step
S42 in the flowchart of FIG. 21 with "the process of generating the
second displacement data." In the process of printing the ruled
lines (the sub-scan-induced displacement detection pattern) at step
S21 in the flowchart of FIG. 13, the sub-scan-induced displacement
detection pattern recording unit 628 causes dots to be recorded
with an identical nozzle in each pass of the main scan while
causing one pass of the sub-scan set for each dot record mode to be
carried out between adjoining passes of the main scan. This
application enables the desired dot record mode to be newly set on
every variation in sub-scan-induced displacement from the original
settings.
[0164] (4) Other Applications
[0165] The generation of the first displacement data (see FIG. 11),
the generation of the second displacement data (see FIG. 13), and
the selection of the dot record mode (see FIGS. 10 and 21) may be
carried out at various timings in the following stages, in addition
to the above applications:
[0166] (a) in the stage of manufacturing the color printer 22;
and
[0167] (b) in the stage of using the color printer 22.
[0168] For example, the arrangement of causing the individual color
printers 22 to undergo the series of processing shown in FIG. 10 or
FIG. 21, FIG. 11, and FIG. 13 in the stage (a), that is, in the
stage of manufacturing the color printer 22, enables the desired
dot record mode attaining the high picture quality to be set in
each color printer 22 before delivery. The performances of the
color printer 22 vary with time. There is accordingly a possibility
that the desired dot record mode attaining the high picture quality
also varies with time. The arrangement of enabling the desired dot
record mode to be newly set after the start of using the color
printer 22 reduces the deterioration of the picture quality with
time to some extent. From this point of view, the preferable
arrangement enables the series of processing shown in FIG. 10 or
FIG. 21, FIG. 11, and FIG. 13 to be carried out in the stage
(b).
[0169] The procedure of the embodiment calculates and evaluates the
displacement of dot recording position with regard to each raster
line on the printing paper in each dot record mode, based on the
first displacement data and the second displacement data. It is,
however, not necessary to calculate the displacement of dot
recording position with regard to all the raster lines on the
printing paper. For example, one modified procedure evaluates the
displacement of dot recording position in each dot record mode,
based on the displacement data with regard to one selected number
of raster lines. Another modified procedure calculates the
displacement of dot recording position with regard to each of the
raster lines recorded through a combination of sub-scan feeds set
for each dot record mode and determines the evaluation value in the
dot record mode. The restricted number of raster lines of interest,
which are the object of the calculation, desirably relieves the
loading of calculation.
[0170] The preferable application calculates and evaluates the
displacements of dot recording positions on the raster lines with
respect to nozzles for a plurality of different color inks in each
dot record mode, although the above description regards the
processing with respect to nozzles for one color ink. The procedure
generates the first displacement data with regard to nozzles for
plural colors at step S1, calculates the displacements of dot
recording positions with regard to nozzles for the respective
colors at step S4, and determines the evaluation values based on
the calculated displacements of dot recording positions for the
respective colors at step S5. One modified procedure selectively
calculates and evaluates the displacement of dot recording position
with regard to a specific color ink that makes the banding
conspicuous. This arrangement desirably relieves the loading of the
processing while effectively reduces the conspicuousness of the
banding.
[0171] In the above embodiment and its modifications, the print
mode selection information, which is used to select the desired dot
record mode, is stored in the rewritable PROM 42. This arrangement
causes the print mode selection information for specifying the
desired dot record mode to be kept in the color printer 22, while
enabling the print mode selection information to be rewritten
according to the requirements.
[0172] The timing of reading the parameters of the desired dot
record mode from the PROM 42 is not restricted to the time of
installing the printer driver 96. But there may be many
modifications. One modified application reads the parameters from
the PROM 42 on every power supply to the computer 90. Even when the
printer 22 connected to the computer 90 is replaced with a new one,
this arrangement enables the parameters of the desired dot record
mode to be read from the PROM 42 in the new printer 22. Another
modified application reads the parameters from the PROM 42 on every
execution of the printing operation (for example, in response to
every user's printing instruction). This application is preferable
in the case where a large number of printers of the identical model
are connected to a network and the user selects one of such
printers for the actual printing operation. The parameters of the
desired dot record mode are read from the PROM 42 in the selected
printer on every execution of the printing operation. This
arrangement enables the printing operation to be carried out in the
dot record mode suitable for the selected printer.
[0173] In the structure that all the dot record mode information is
registered in advance in the printer driver 96, the printer driver
96 reads only the print mode selection information from the PROM
42. Here it is assumed that an error of reading the print mode
selection information occurs, for example, due to a failure in
bidirectional data communication. In this case, the printer driver
96 causes the printer 22 to print the print mode selection
information (that is, the record mode number) on a printing medium,
while requesting the user to input the printed print mode selection
information (record mode number) on its user interface displayed on
the screen of the computer 90. For example, a sentence like "Input
printed record mode number through keyboard" is displayed in the
user interface area on the screen. This arrangement enables the
printer driver 96 to carry out various series of processing with
the parameters of the dot record mode corresponding to the print
mode selection information input by the user.
[0174] As described above, the procedure of the embodiment enables
the desired dot record mode attaining the high picture quality to
be selected among a plurality of dot record modes having at least
the same resolution. This arrangement enables a high-quality image
to be recorded according to the conditions of the individual color
printer 22.
[0175] This advantage of recording the high-quality image according
to the condition of the individual printer is especially prominent
in the case where there are a plurality of equivalent dot record
modes having different sequences of the feeding amounts of sub-scan
L but the same resolution and recording speed like the first dot
recording mode and the second dot recording mode at k=4 discussed
above.
[0176] The above embodiment and its modifications are to be
considered in all aspects as illustrative and not restrictive.
There may be many modifications, changes, and alterations without
departing from the scope or spirit of the main characteristics of
the present invention. All changes within the meaning and range of
equivalency of the claims are therefore intended to be embraced
therein. Some examples of possible modification are discussed
below. For example, the image sensor 320 may be incorporated in the
printer 22 or in an image scanner or reader separate from the
printer 22. The structure of incorporating the image sensor 320 in
the printer 22 advantageously enables the recording position of the
ruled line to be read in the course of printing the ruled line.
[0177] In one preferable application, an appropriate print head is
selected among a plurality of print heads, which are attachable to
one scan drive unit, based on the second displacement data of the
scan drive unit and the first displacement data of the respective
print heads. Even when the scan drive unit has significantly large
errors of sub-scan feed, the combination of the scan drive unit
with the suitable print head enables the scan drive unit to be used
efficiently, thus attaining the effective use of the product. In a
similar manner, an appropriate scan drive unit may be selected
among a plurality of scan drive units, to which one print head is
attachable, based on the first displacement data of the print head
and the second displacement data of the respective scan drive
units. This application enables even a print head having a
significantly large displacement of dot recording position to be
used efficiently.
[0178] The principle of the present invention is applicable to
monochromatic printing as well as color printing. The technique of
the present invention is also applicable to variable-dot printers
that create a plurality of dots in each pixel to attain the
multi-tone expression and to drum scan printers. In the drum scan
printer, the rotating direction of the drum corresponds to the main
scanning direction and the feeding direction of the carriage
corresponds to the sub-scanning direction. The principle of the
present invention is applicable to not only the ink jet printers
but any dot recording apparatuses that record dots on the surface
of a printing medium with a dot record head having an array of
plural dot forming elements. The dot forming elements here
represent elements used for creating dots, for example, nozzles in
the ink jet printers.
[0179] The embodiment and its modifications are described on the
assumption that ink is a liquid. The ink may be solidified at or
below room temperature or may be softened or liquefied at room
temperature. The ink jet printer generally has a temperature
regulation mechanism that keeps the temperature of ink in a range
of 30.degree. C. to 70.degree. C. to maintain the viscosity of ink
in a stable ejection range. In any case, the technique of the
present invention is applicable to the ink that is in the liquid
state at the time of inputting the dot recording signals to the
printer.
[0180] With a view to preventing evaporation of ink or utilizing
the thermal energy in the printer for the change of ink from the
solid state to the liquid state, the ink may be in the solid state
at room temperature and liquefied under application of heat. The
principle of the present invention is applicable to the ink that is
liquefied under application of thermal energy in response to the
input of the dot recording signals. Here the ink ejected in the
liquid state may immediately be solidified on the printing medium.
The ink may be accommodated in the liquid state or in the solid
state in through holes or recesses of a porous sheet and be
arranged opposite to a converter that converts electrical energy to
thermal energy as disclosed in JP54-56847A and JP60-71260A. The
technique of the present invention is especially effective for the
ink that is liquefied under application of heat.
[0181] In the embodiment and its modified examples, part of the
hardware configuration may be replaced by the software. On the
contrary, part of the software may be replaced by the hardware
configuration. For example, the functions of the control circuit 40
(see FIG. 2) in the color printer 22 may be executed by the
computer 90. In this case, computer programs like the printer
driver 96 actualize the functions of the control circuit 40.
[0182] The computer programs that attain the various functions are
recorded in computer readable recording media, such as floppy disks
and CD-ROMs. The computer 90 reads the computer programs from the
recording media and transfers the computer programs to an internal
storage device or an external storage device. The computer programs
may alternatively be supplied to the computer 90 from a program
supply unit via a communication path. The microcomputer in the
computer 90 executes the computer programs stored in the internal
storage device or the external storage device or directly executes
the computer programs recorded in the recording media to attain the
various functions.
[0183] In the specification hereof, the computer 90 is the concept
including both the hardware structure and the operating system.
Namely the computer represents the hardware structure working under
the control of the operating system. The computer 90 executes
various application programs to attain the functions discussed
above. Part of such functions may be actualized by the operating
system, instead of the application programs.
[0184] In the present invention, the computer readable recording
media are not restricted to portable recording media, such as
flexible disks and CD-ROMs, but includes a diversity of internal
storage devices like a RAM and a ROM included in the computer and a
diversity of external storage devices like a hard disk fixed to the
computer. Although the present invention has been described and
illustrated in detail, it is clearly understood that the same is by
way of illustration and example only and is not to be taken by way
of limitation, the spirit and scope of the present invention being
limited only by the terms of the appended claims.
* * * * *