Patent US1330451A successfully refreshed from Google Patents.
Patent EP0719033A2 successfully refreshed from Google Patents.
EP0719033A2
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Image processing method and apparatus and image forming method and apparatus using the same
Assignee: Canon Inc
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Filing: 1995-12-19
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Granted: —
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Expires: 2015-12-19
Abstract
Abstract An image can be outputted with a high sharpness without deteriorating a resolution. In order to output an image of a high picture quality while suppressing the occurrence of a moire, an exposure amount is modulated in accordance with pixel density information of the image divided into pixels of a predetermined size by an exposure amount modulating unit 15 in a light scanning unit 1, thereby expressing an image dark/light state. In this case, in a highlight density region in which a pixel density is equal to or less than 1/3 of the maximum image density, the density data of two adjoining pixels is modulated by one pixel and the other pixel is not recorded. In a density region in which the image density lies within a range from 1/3 to 1/2 of the maximum image density, a part of the density data of one of the two adjoining pixels is transposed to the other pixel. In a density region in which the image density is equal to or larger than 1/2 of the maximum density, the pixel transposition is not performed. <IMAGE>
Inventors
- 👤 Jun Canon K.K. Koide
- 👤 Yuichi C/O Canon K.K. Ikeda
- 👤 Nobuatsu C/O Canon K.K. Sasanuma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:33
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4057; H04N1/4056
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
98 words
An image forming apparatus comprising: input means for inputting digital image data of every pixel; evaluating means for evaluating a density of the image data inputted by said input means by at least three stages; concentrating means for concentrating said digital image data every said pixel in accordance with the stage evaluated by said evaluating means; modulating means for performing a signal modulation in accordance with a level of said digital image data concentrated by said concentrating means; and image forming means for forming an image in accordance with the digital image data modulated by said modulating means.
Claim 2
Dependent Claim
41 words
An apparatus according to claim 1, wherein said evaluating means includes: adding means for adding data of two adjoining pixels; and comparing means for comparing the data added by said adding means and at least two threshold levels which are different.
Claim 3
Dependent Claim
25 words
An apparatus according to claim 1, wherein said concentrating means includes means for adding said digital image data at a predetermined ratio every adjoining pixels.
Claim 4
Dependent Claim
25 words
An apparatus according to claim 3, wherein said ratio changes to at least two stages in accordance with the stage evaluated by said evaluating means.
Claim 5
Dependent Claim
15 words
An apparatus according to claim 1, wherein said modulating means is pulse width modulating means.
Claim 6
Dependent Claim
19 words
An apparatus according to claim 1, wherein said image forming means is image forming means of an electrophotography system.
Claim 7
Dependent Claim
29 words
An apparatus according to claim 6, wherein said image forming means includes means for scanning on a photosensitive material by a light beam modulated by pulse width modulating means.
Claim 8
Dependent Claim
24 words
An apparatus according to claim 7, further comprising developing means for developing a latent image formed by said light beam on said photosensitive material.
Claim 9
Dependent Claim
17 words
An apparatus according to claim 8, wherein said developing means develops said latent image by a toner.
Claim 10
Dependent Claim
41 words
An image processing method comprising the steps of: inputting image data every pixel; evaluating a density of said inputted image data by at least three stages; and adding the image data of every pixel on the basis of said evaluated stage.
Claim 11
Dependent Claim
35 words
A method according to claim 10, wherein said evaluating step includes the steps of: adding data of two adjoining pixels; and comparing the added data of said two adjoining pixels and a predetermined threshold value.
Claim 12
Dependent Claim
37 words
A method according to claim 10, wherein said adding step includes the step of changing a ratio of the addition of the image data of every said two adjoining pixels on the basis of the evaluated stage.
Claim 13
Dependent Claim
29 words
A method according to claim 10, further comprising the step of outputting the image data of every pixel added by said adding step to a visible image reproducing device.
Claim 14
Dependent Claim
15 words
A method according to claim 13, wherein said visible image reproducing device is a printer.
Claim 15
Dependent Claim
89 words
An image forming method comprising the steps of: evaluating given image data of every pixel of 400 d.p.i. or more; concentrating the image data of every said pixel in accordance with said evaluation; irradiating a light beam having a diameter of 45 µm which was area modulated in accordance with said concentrated image data onto a photosensitive material; developing said photosensitive material by a toner in which a substantial grain size is equal to or less than 7 µm; and transferring said developed toner image onto a recording material.
Claim 16
Dependent Claim
19 words
A method according to claim 15, wherein in said concentrating step, the data of two adjoining pixels is added.
Claim 17
Dependent Claim
27 words
A method according to claim 15, wherein in said evaluating step, a value of the image data of said every pixel is compared with a threshold value.
Claim 18
Dependent Claim
19 words
A method according to claim 15, wherein said image data includes image data of a plurality of color components.
Claim 19
Dependent Claim
20 words
A method according to claim 18, wherein said image data includes a plurality of color components including a black component.
Claim 20
Dependent Claim
19 words
A method according to claim 18, wherein said concentration is executed with respect to at least the black component.
Claim 21
Dependent Claim
22 words
A method according to claim 15, further comprising the step of fixing said toner image which was transferred to said recording material.
Claim 22
Dependent Claim
131 words
An image forming apparatus for expressing a density by a pixel modulation, comprising: storing means for storing pixel data; detecting means for extracting two adjoining pixels from said pixel data and detecting a sum of density values which are expressed by said two pixels; comparing means for comparing the sum of said density values detected by said detecting means and a predetermined density value; and changing means for moving a part of the density value of one of said two pixels to the other pixel and changing the density values of said two pixels in the case where the sum of the density values of said two pixels which was detected by said detecting means is lower than a predetermined density value as a result of comparison by said comparing means.
Claim 23
Dependent Claim
128 words
An apparatus according to claim 22, wherein as for the density values which are expressed by said two pixels, when it is now assumed that the pixel density of one of said adjoining pixels is set to a and the other pixel density is set to b and, further, a maximum density value of an image which is formed by the image forming apparatus is set to C, said predetermined density value in said comparing means is equal to C, and when C > a + b is satisfied, as new pixel densities, said changing means calculates a' and b' by the following equations: a' = a + b[1 - {(a + b)/C}N] b' = b{(a + b)/C}N where, N is a positive integer of 1 or more.
Claim 24
Dependent Claim
17 words
An apparatus according to claim 23, wherein said N is a real number of 2 to 3.
Claim 25
Dependent Claim
17 words
An apparatus according to claim 22, further having setting means for setting a value of said N.
Claim 26
Dependent Claim
136 words
An image forming method of expressing a density by a pixel modulation, comprising: a storing step of storing pixel data; a detecting step of extracting two adjoining pixels from said pixel data and detecting a sum of density values which are expressed by said two pixels; a comparing step of comparing the sum of the density values which was detected in said detecting step and a predetermined density value; and changing step of moving a part of the density value of one of said two pixels to the other pixel and changing the density values of said two pixels in the case where the sum of the density values of said two pixels which was detected in said detecting step is lower than said predetermined density value as a result of comparison in said comparing step.
Claim 27
Dependent Claim
155 words
An image forming apparatus in which a multi-potential latent image is formed on a charged photosensitive material by a light scan of light scanning means, a visible image is formed by depositing a developing agent onto said multi-potential latent image, and said visible image is transferred to a transfer material and is outputted, wherein said light scanning means has exposure amount modulating means for modulating an exposure amount in accordance with pixel density information and expressing an image dark/light state for pixels on said photosensitive material divided into a predetermined size, and said exposure amount modulating means divides an image density region to a highlight density region, a halftone density region, or a dark density region, modulates the density data of a predetermined number of pixels which are continuous in a light scanning direction by the density data of several pixels among said pixels in said highlight density region, and doesn't record the remaining pixels.
Claim 28
Dependent Claim
45 words
An apparatus according to claim 27, wherein when said image density region is the highlight density region, the modulation is executed by one pixel of the density data of the two adjoining pixels in the light scanning direction and the other pixel is not recorded.
Claim 29
Dependent Claim
33 words
An apparatus according to claim 27, wherein when said image density region is a region in a range from the halftone density region to the dark density region, each pixel is individually modulated.
Claim 30
Dependent Claim
79 words
An apparatus according to claim 27, wherein when said image density region is the halftone density region, said one pixel modulated in said highlight density region is set to a fixed value and the density data in which the density data of one pixel is subtracted from the density data of two pixels is modulated by the density data of the other pixel, and when said image density region is the dark density region, each pixel is individually modulated.
Claim 31
Dependent Claim
32 words
An apparatus according to claim 27, wherein said visible image is constructed in a raster-like array and a pixel density of said raster-like array is equal to or larger than 600 d.p.i.
Claim 32
Dependent Claim
57 words
Image processing apparatus comprising evaluating means for evaluating a density of image data into a plurality of stages, concentrating means for concentrating the image data in accordance with the stage evaluated by the evaluating means, and modulating means for modulating the image data in accordance with a level of said image data concentrated by said concentration means.
Claim 33
Dependent Claim
44 words
An image processing method comprising the steps of evaluating a density of image data into a plurality of stages, concentrating the image data in accordance with the evaluated stage, and modulating the image data in accordance with a level of the concentrated image data.
References Cited (Backward Citations)
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