# US 5,327,252 A · Print evaluation apparatus

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- Number: US 5,327,252 A
- Document ID: US5327252A
- Status: Granted
- Kind: A
- Application number: 07/764,364
- Filed: 1991-09-23
- Granted: 1994-07-05
- Earliest claimed: 1990-09-21
- Assignees: Canon Kabushiki Kaisha
- Inventors: Shinsuke Tsuruoka; Hiroshi Haruyama; Hideaki Uemura
- Web page: https://patentgrep.com/patent/US5327252A

## CPC

- H04N 1/00015: {Reproducing apparatus}
- H04N 1/00002: {Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for (error detection, error correction or monitoring in digital computers or digital computer components G06F11/00)}
- H04N 1/00031: {Testing, i.e. determining the result of a trial (H04N1/00029 takes precedence; using test signals for transmission mode changing H04N2201/33371)}
- H04N 1/00045: {using a reference pattern designed for the purpose, e.g. a test chart}
- H04N 1/00058: {using a separate apparatus}
- H04N 1/00063: {using at least a part of the apparatus itself, e.g. self-testing}
- H04N 1/047: Detection, control or error compensation of scanning velocity or position ({H04N1/0402 and } H04N1/17 take precedence)
- H04N 1/4078: {using gradational references, e.g. grey-scale test pattern analysis}
- H04N 2201/04712: using unbroken arrays of detectors, i.e. detectors mounted on the same substrate
- H04N 2201/04717: on the scanned sheet, e.g. a reference sheet
- H04N 2201/04729: in the main-scan direction
- H04N 2201/04731: in the sub-scan direction
- H04N 2201/04734: Detecting at frequent intervals, e.g. once per line for sub-scan control
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A print evaluating apparatus includes an image reader having a plurality of photoreceptors to read a print pattern line by line; a relative movement causing device for imparting relative movement between the print pattern and the image reader in a direction different from a direction in which the photoreceptors are arranged; and a processor for effecting plural operations in parallel for plural evaluation items for image signals corresponding to the print pattern supplied by the image reader during the relative movement, and for effecting evaluation on data provided by the operations.

## Claims

### Claim 1

A print evaluating apparatus, comprising:
reading means having a plurality of photoreceptors to read a print pattern line by line;
relative movement means for imparting relative movement between the print pattern and said reading means in a direction different from a direction in which said photoreceptors are arranged; and
processing means for effecting plural operations in parallel for plural evaluation items for image signals corresponding to the print pattern supplied by said reading means during the relative movement, and for effecting evaluation on data provided by the operations, wherein said print pattern has plural pattern areas corresponding to the plural evaluation items, and wherein said processing means effects the parallel operation for the respective pattern areas.

### Claim 2 (depends on 1)

An apparatus according to claim 1, wherein said processing means has plural operation processors for carrying out different processing operations.

### Claim 3 (depends on 1, 2)

An apparatus according to claim 1 or 2 wherein said processing means converts the image signals supplied from said reading means to digital signals and processes the digital signals.

### Claim 4

A print evaluation apparatus, comprising:
reading means for reading a print evaluation pattern having plural pattern areas corresponding to plural evaluation items; and
processing means for effecting print evaluations for the plural evaluation items on the basis of image signals corresponding to the plural area patterns supplied from said reading means.

### Claim 5 (depends on 4)

An apparatus according to claim 4, wherein said pattern includes a combination of at least two of a printable region frame pattern, a density evaluation pattern, a local magnification evaluation pattern and a constant pitch horizontal line pattern for evaluation of sheet feed.

### Claim 6 (depends on 4)

An apparatus according to claim 4, wherein said processing means effects the print evaluations in parallel.

### Claim 7 (depends on 4, 5, 6)

An apparatus according to claim 4, 5 or 6, wherein said processing means converts the image signals supplied from said reading means to digital signals and processes the digital signals.

### Claim 8

A print evaluation apparatus, comprising:
first reading means having a plurality of photoreceptors to read a pattern on a print;
second reading means having a plurality of photoreceptors to read the pattern;
relative movement means for imparting relative movement between said first reading means and the print and between said second reading means and the print in a direction which is different from a direction in which said plural photoreceptors are arranged;
first processing means for effecting first print evaluation on the basis of image signals supplied from said first reading means; and
second processing means for effecting second print evaluation on the basis of image signals supplied from said second reading means;
wherein said first and second reading means have different resolution powers.

### Claim 9 (depends on 8)

An apparatus according to claim 8, wherein said first and second processing means effect the first and second print evaluations on the basis of the image signals from said first and second reading means during the relative movement.

### Claim 10 (depends on 8)

An apparatus according to claim 8, wherein said first and second reading means cover different areas of the pattern.

### Claim 11 (depends on 8, 9, 10)

An apparatus according to claim 8, 9 or 10, wherein said first and second processing means convert image signals from said reading means to digital signals, and process the digital signals to effect the first and second print evaluations.

### Claim 12

A print evaluation apparatus, comprising:
reading means having a plurality of photoreceptors to read a pattern line by line;
relative movement means for imparting relative movement between the print pattern and said reading means in a direction which is different from a direction in which said photoreceptors are arranged;
memory means for storing movement distance data relating to a movement distance imparted by said moving means in association with a reading timing of the operation of said reading means; and
processing means for effecting print evaluation on the basis of image signals from said reading means and the movement distance data supplied during the relative movement.

### Claim 13 (depends on 12)

An apparatus according to claim 12, wherein the pattern is a line pattern including lines at a constant pitch in the direction of the relative movement.

### Claim 14 (depends on 13)

An apparatus according to claim 13, wherein said processing means effects print evaluation on the basis of a pitch of the lines, and wherein positional data of the line pattern for determining the pitch are corrected on the basis of second data stored in said memory means.

### Claim 15 (depends on 14)

An apparatus according to claim 14, wherein said processing means converts the image signals supplied from said reading means to digital signals and processes the digital signals.

### Claim 16

A print evaluation apparatus, comprising:
reading means for reading a line pattern having lines printed at a constant pitch in a direction of relative movement between printing means and a print on which the pattern is printed;
projecting means for determining projective data of image signals supplied from said reading means in a direction of length of the lines;
processing means for determining pitch data relating to a pitch of the lines on the basis of the projective data and effecting an evaluation relating to the relative movement on the basis of the pitch data.

### Claim 17 (depends on 16)

An apparatus according to claim 16, wherein said projection means converts image signals from said reading means to digital signals, and processes the digital signals to provide the projective data.

### Claim 18 (depends on 17)

An apparatus according to claim 17, wherein said processing means determines a peak position of the projective data, and provides the pitch data from an interval between adjacent peak positions.

### Claim 19 (depends on 18)

An apparatus according to claim 18, wherein said processing means determines a variance of the intervals to effect the evaluation relating to the relative movement.

### Claim 20 (depends on 17)

An apparatus according to claim 17, wherein said processing means determines a maximum and/or a minimum of the intervals, and compares the a maximum and/or a the minimum with a tolerable level to effect the evaluation relating to the relative movement.

### Claim 21

A print evaluation apparatus, comprising:
reading means for reading a line pattern having lines printed at a constant pitch on a print in a direction of relative movement between printing means and the print;
projection means for providing projective data of image signals from said reading means in a direction of length of the lines; and
processing means for determining constrast data relating to a contrast between the line and a background on the basis of the projective data and for effecting an evaluation on the basis of the contrast data.

### Claim 22 (depends on 21)

An apparatus according to claim 21, wherein said projection means converts image signals from said reading means to digital signals, and processes the digital signals to provide the projective data.

### Claim 23 (depends on 22)

An apparatus according to claim 22, wherein said processing means effects the evaluation on the basis of a difference of peak values of the projective data corresponding to an adjacent line and background.

### Claim 24 (depends on 23)

An apparatus according to claim 23, wherein said processing means effects the evaluation on the basis of profile of a frequency distribution of the differences.

### Claim 25

A print evaluation apparatus, comprising:
reading means having a plurality of photoreceptors for reading a pattern on a print line by line;
relative movement means for imparting relative movement between said reading means and the print in a direction which is different from a direction in which the photoreceptors are arranged; and
processing means for determining end position information of the print and pattern position information of the pattern on the basis of image signals supplied from said reading means during the relative movement, for processing the end position information and the pattern position information to determine a positional relation between the end of the print and the pattern, and for evaluating a print position accuracy.

### Claim 26 (depends on 25)

An apparatus according to claim 25, wherein said processing means determines plural pieces of information for plural pieces of end position information and the pattern, and processes the pieces of informations to evaluate the print position.

### Claim 27 (depends on 25, 26)

An apparatus according to claim 25 or 26, wherein said processing means converts the image signals supplied from said reading means to digital signals and processes the digital signals.

### Claim 28

A print evaluation apparatus, comprising:
reading means having a plurality of photoreceptors to read a printed line pattern line by line;
relative movement means for imparting relative movement between said reading means and the line pattern in a direction different from a direction in which the plural photoreceptors are arranged;
calculating means for calculating first information relating to an end position of the line pattern and second information relating to a width of the pattern on the basis of the image signals supplied from said reading means during the relative movement; and
processing means for effecting linearity evaluation of the line pattern on the basis of central position information determined from said first information and second information and on the basis of a line to which the line pattern is approximated.

### Claim 29 (depends on 28)

An apparatus according to claim 28, wherein said processing means calculates a distance between the central position information and the approximated line, and the calculated result is compared with a tolerable level.

### Claim 30 (depends on 28)

An apparatus according to claim 28, wherein the end position is a start position of the line pattern.

### Claim 31 (depends on 28, 29, 30)

An apparatus according to claim 28, 29 or 30, wherein said processing means converts the image signals supplied from said reading means to digital signals and processes the digital signals.

### Claim 32

A print evaluating method, comprising the steps of:
a first step of imparting relative movement between a print patten and a reading means which reads the print pattern in a direction different from a direction in which a plurality of photoreceptors of the reading means are arranged, the print pattern having plural areas corresponding to plural evaluation items;
a second step of effecting plural operations in parallel for plural evaluation items for an image signal, corresponding to the print pattern, output from said reading means during the relative movement of said first step; and
a third step of effecting an evaluation with respect to the evaluation items on the basis of data provided by the operations of said second step.

### Claim 33 (depends on 32)

A method according to claim 32, wherein in said second step, the plural operations are carried out by different operation processors.

### Claim 34 (depends on 32, 33)

A method according to claim 32 or 33, wherein in said second step, the image signal is A/D converted, and said operations are effected for the A/D converted data.

### Claim 35 (depends on 32)

A method according to claim 32, wherein in said first step, the relative movement is effected a plurality of times, and in said second step, the operations are effected for the image data from the reading means.

### Claim 36 (depends on 35)

A method according to claim 35, wherein in said first step, said reading means is reciprocated relative to the print pattern, and said operations are effected for the image data output from the reading means during both forward and backward movements of the reciprocation.

### Claim 37 (depends on 32, 33, 35)

A method according to any one of claims 32, 33, 35, or 36, wherein the print pattern includes a printable region frame pattern, and a print position accuracy is evaluated on the basis of the image signal corresponding to the printable region frame pattern.

### Claim 38 (depends on 32, 33, 35)

A method according to any one of claim 32, 33, 35, or 36, wherein the print pattern includes a printable region frame pattern, and a print linearity is evaluated on the basis of the image signal corresponding to the printable region frame pattern.

### Claim 39 (depends on 32, 33, 35)

A method according to any one of claim 32, 33, 35, or 36, wherein the print pattern includes an image density evaluation pattern, and an image density is evaluated on the basis of the image signal corresponding to the image density evaluation pattern.

### Claim 40 (depends on 32, 33, 35)

A method according to any one of claim 32, 33, 35, or 36, wherein the print pattern includes a partial magnification measuring pattern, and a partial magnification is evaluated on the basis of the image signal corresponding to the partial magnification measuring pattern.

### Claim 41 (depends on 32, 33, 35)

A method according to any one of claim 32, 33, 35, or 36, wherein the print pattern includes a sheet feed evaluation pattern, and uniformity of sheet feed is evaluated on the basis of the image signal corresponding to the sheet feed evaluation pattern.

### Claim 42

A print evaluating method, comprising the steps of:
a first step of reading, using reading means, a print pattern on a print including plural measurement regions corresponding to plural evaluation items; and
a second step of effecting evaluations with respect to the plural evaluation items on the basis of an image signal corresponding to the plural measurement regions produced by the reading means.

### Claim 43 (depends on 42)

A method according to claim 42, wherein in said second step, said evaluations are effected in parallel.

### Claim 44 (depends on 42)

A method according to claim 42, wherein in said second step, the image signal is A/D converted, and said evaluations are effected for the A/D converted data.

### Claim 45 (depends on 42)

A method according to claim 42, wherein the evaluations are effected by different operation processors.

### Claim 46 (depends on 42)

A method according to claim 42, wherein said print pattern includes a measurement region for evaluation of a print linearity.

### Claim 47 (depends on 42)

A method according to claim 42, wherein said print pattern includes a measurement region for evaluation of a print density.

### Claim 48 (depends on 42)

A method according to claim 42, wherein said print pattern includes a measurement region for evaluation of a partial magnification.

### Claim 49 (depends on 42)

A method according to claim 42, wherein said print pattern includes a measurement region for evaluation of sheet feed.

### Claim 50

A print evaluating method, comprising the steps of:
a first step of reading a print pattern on a print using first reading means with a first measurement resolution power;
a second step of reading the print pattern using second reading means with a second measurement resolution power which is different from the first measurement resolution power;
a third step of effecting a first print evaluation on the basis of an image signal corresponding to the print pattern read in said first step; and
a fourth step of effecting a second print evaluation, which is different from the first evaluation, on the basis of an image signal corresponding to the print pattern read in said second step.

### Claim 51 (depends on 50)

A method according to claim 50, wherein the first reading means and the second reading means are moved relative to the print pattern, in said first and second steps.

### Claim 52 (depends on 51)

A method according to claim 51, wherein said first and second print evaluations are effected on the basis of the image signal from said first and second reading means during the relative movement.

### Claim 53 (depends on 50)

A method according to claim 50, wherein regions in the print pattern read by the first and second reading means are different.

### Claim 54 (depends on 50)

A method according to claim 50, wherein in said third and fourth steps, the image signal is A/D converted, and operations are effected for digital signals provided by the A/D conversion to effect the first and second evaluations.

### Claim 55

A print evaluating method, comprising the steps of:
a first step of imparting relative movement between a print pattern and a reading means in a direction different from a direction in which a plurality of photoreceptors of the reading means are arranged;
a second step of storing data of a distance of the movement in said first step in association with a read timing of said reading means;
a third step of effecting a print evaluation on the basis of (i) an image signal from said reading means during the relative movement and (ii) the stored data.

### Claim 56 (depends on 55)

A method according to claim 55, wherein the print pattern comprises lines printed at regular intervals in a direction of the relative movement.

### Claim 57 (depends on 56)

A method according to claim 56, wherein in said third step, the evaluation is effected by obtaining intervals between the lines on the basis of positions thereof.

### Claim 58 (depends on 57)

A method according to claim 57, wherein the positions of the lines are corrected on the basis of the stored data.

### Claim 59 (depends on 57)

A method according to claim 57, wherein the image signal is A/D converted, and a predetermined operation is effected for digital signals provided by the A/D conversion to determine the intervals.

### Claim 60

A print evaluating method, comprising the steps of:
a first step of reading a pattern comprising lines on a print, the lines being printed at predetermined intervals in a direction of relative movement between the print and a reading means;
a second step of obtaining projective data in a direction of a length of the line pattern on the basis of an image signal corresponding to the line pattern read in said first step;
a third step of obtaining interval data relating to the intervals of the line pattern on the basis of the projective data obtained in said second step;
a fourth step of effecting an evaluation of the relative movement on the basis of the interval data obtained in said third step.

### Claim 61 (depends on 60)

A method according to claim 60, wherein the image signal is A/D converted, and a predetermined operation is effected for digital signals provided by the A/D conversion to obtain the projective data.

### Claim 62 (depends on 61)

A method according to claim 61, wherein in said third step, peak positions of the projective data are determined, and the interval data are obtained from intervals between adjacent peak positions.

### Claim 63 (depends on 62)

A method according to claim 62, wherein in said fourth step, the evaluation is effected on the basis of a variance of the peak position data in accordance with the interval data.

### Claim 64 (depends on 61)

A method according to claim 61, wherein in said fourth step, a maximum and/or a minimum of the intervals between the peak positions are determined in accordance with the interval data, and the evaluation is effected on the basis of the maximum and/or minimum compared with a reference.

### Claim 65

A print evaluating method, comprising the steps of:
a first step of reading a pattern comprising lines on a print, the lines being printed at predetermined intervals in a direction of relative movement between the print and a reading means;
a second step of obtaining projective data in a direction of a length of the line pattern on the basis of an image signal corresponding to the line pattern read in said first step;
a third step of obtaining contrast data relating to a contrast of the lines and a background thereof on the basis of the projective data obtained in said second step;
a fourth step of effecting an evaluation of the printing on the basis of the contrast data obtained in said third step.

### Claim 66 (depends on 65)

A method according to claim 65, wherein the image signal is A/D converted, and a predetermined operation is effected for digital signals provided by the A/D conversion to obtain the projective data.

### Claim 67 (depends on 66)

A method according to claim 66, wherein the contrast data represent differences of peaks of the projective data of adjacent lines and background.

### Claim 68 (depends on 67)

A method according to claim 67, wherein in said fourth step 4, the evaluation is effected in accordance with a configuration of a frequency distribution of the differences.

### Claim 69

A print evaluating method, comprising the steps of:
a first step of imparting relative movement between a print and a reading means in a direction different from a direction in which a plurality of photoreceptors of the reading means are arranged, the print having a predetermined print pattern;
a second step of obtaining end position information of the print and pattern position information on the basis of an image signal from said reading means during the relative movement of said first step; and
a third step of effecting an evaluation of print position accuracy on the basis of the end position information of the print and the pattern position information.

### Claim 70 (depends on 69)

A method according to claim 69, wherein in said second step, plural pieces of the end position information and plural pieces of the pattern position information are obtained, and in said third step, a predetermined operation is effected for the plural pieces of the end position information and the plural pieces of the pattern position information to evaluate the print position accuracy.

### Claim 71 (depends on 69)

A method according to claim 69, wherein the image signal is A/D converted, and the end position information and pattern position information are obtained on the basis of digital signals provided by the A/D conversion.

### Claim 72

A print evaluating method, comprising the steps of:
a first step of reading a line pattern on a print by a reading means having plural photoreceptors;
a second step of obtaining first information on an end position of the line pattern and second information on a width of a line pattern on the basis of an image signal output from said reading means;
a third step of obtaining information on a center position of the line pattern and an approximated line on the basis of the first information and the second information; and
a fourth step of evaluating a linearity of the line pattern from the center position information and the approximated line obtained in said third step.

### Claim 73 (depends on 72)

A method according to claim 72, wherein in said fourth step, a distance between the center position information and the approximated line is calculated, and a result of the calculation is compared with a reference, by which the linearity is evaluated.

### Claim 74 (depends on 72)

A method according to claim 72, wherein the end position is a start position of the line pattern.

### Claim 75 (depends on 72)

A method according to claim 72, wherein in said first step, the line pattern is read while imparting relative movement between the reading means and the print in a direction different from a direction in which the photoreceptors are arranged.

### Claim 76 (depends on 72)

A method according to claim 72, wherein the image signal is A/D converted, and the first information and the second information are obtained in accordance with a digital signal provided by the A/D conversion.