Patent EP0804014A1 successfully refreshed from Google Patents.
EP0804014A1
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EP
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Variable resolution laser printer
Assignee: Konica Minolta Inc
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Filing: 1997-04-25
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Granted: —
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Expires: 2017-04-25
Abstract
Abstract An image forming apparatus includes: a photoreceptor; writing exposure device for forming a latent image on the photoreceptor; developing device for developing the latent image to form a toner image; transfer device for transferring the toner image onto a recording sheet; fixing device for fixing the toner image on the recording sheet; switching device for switching a plurality of recording pixel densities; and correcting device for correcting a maximum image density and gradation of the toner image according to the switched recording pixel density. For the maximum image density correction, a test patch image is formed on the photoreceptor drum. The density is detected with a density detecting sensor. Gradation correction data is generated and interpolated to represent a continuous curve.
Inventors
- 👤 Kunihisa Yoshino
- 👤 Jun Yokobori
- 👤 Kosuke Toura
- 👤 Tetsuya Niitsuma
- 👤 Akitoshi Matsubara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 14:49
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/0402; H04N1/0408; H04N1/042; H04N1/0443; H04N1/23; H04N1/29; H04N1/295; H04N1/40; H04N1/407; H04N1/4076; H04N1/4078; H04N1/113; H04N1/1135; H04N2201/00; H04N2201/04; H04N2201/047; H04N2201/04753; H04N2201/04756
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
91 words
An image forming apparatus comprising: (a) a photoreceptor body; (b) writing exposure means for forming a latent image on the photoreceptor body; (c) developing means for developing the latent image to form a toner image; (d) transfer means for transferring the toner image onto a recording sheet; (e) fixing means for fixing the toner image on the recording sheet; (f) switching means for switching a plurality of recording pixel densities; and (g) correcting means for correcting a maximum image density of the toner image according to the switched recording pixel density.
Claim 2
Dependent Claim
19 words
The image forming apparatus of claim 1, wherein the exposure means is a laser for emitting a laser beam.
Claim 3
Dependent Claim
27 words
The image forming apparatus of claim 2, wherein a switching of the recording pixel density is interlocked with a switching of a power of the laser beam.
Claim 4
Dependent Claim
39 words
The image forming apparatus of claim 1, wherein the correcting means forms a test pattern for correcting the maximum image density, and corrects the maximum image density by detecting density of the test pattern with a density detecting sensor.
Claim 5
Dependent Claim
24 words
The image forming apparatus of claim 4, wherein the test pattern includes a plurality of toner images having image densities different from each other.
Claim 6
Dependent Claim
34 words
The image forming apparatus of claim 4, wherein the correcting means produces data for correcting the maximum image density by detecting the density of the test pattern and stores the data in a memory.
Claim 7
Dependent Claim
33 words
The image forming apparatus of claim 6, wherein when the recording pixel density is switched, the correcting means corrects the maximum image density by calculating the data for correcting the maximum image density.
Claim 8
Dependent Claim
36 words
The image forming apparatus of claim 6, wherein the correcting means corrects the maximum image density by calculating the data for correcting the maximum image density with respect to a second recording pixel density and thereafter.
Claim 9
Dependent Claim
25 words
The image forming apparatus of claim 1, wherein correcting means corrects a gradation property of the toner Image according to the plurality recording pixel densities.
Claim 10
Dependent Claim
44 words
The image forming apparatus of claim 9, wherein when the recording pixel density is switched, the correcting means forms a test pattern for correcting the gradation property and corrects the gradation property by detecting density of the test pattern with a density detecting sensor.
Claim 11
Dependent Claim
24 words
The image forming apparatus of claim 10, wherein the test pattern includes a plurality of toner images having image densities different from each other.
Claim 12
Dependent Claim
33 words
The image forming apparatus of claim 10, wherein the correcting means produces data for correcting the gradation property by detecting the density of the test pattern and stores the data in a memory.
Claim 13
Dependent Claim
42 words
The image forming apparatus of claim 9, wherein after the correcting means corrects a gradation property of a lower recording pixel density from the plurality of recording pixel densities, the correcting means corrects a gradation property of a higher recording pixel density.
Claim 14
Dependent Claim
24 words
The image forming apparatus of claim 9, wherein after the correcting means corrects the maximum image density, the correcting means corrects the gradation property.
Claim 15
Dependent Claim
35 words
The image forming apparatus of claim 1 further comprising a switching control means for controlling image formation conditions according to a switched recording pixel density by the switching means for switching the recording pixel density.
Claim 16
Dependent Claim
58 words
The image forming apparatus of claim 15, wherein the image formation conditions include at least one of an exposure amount of the exposure means, a writing speed of the exposure means, a driving speed of the photoreceptor body, a driving speed of the developing means, a driving speed of the fixing means, and temperature of the fixing means.
Claim 17
Dependent Claim
44 words
The image forming apparatus of claim 1, wherein after the correcting means corrects the maximum image density of a lower recording pixel density from the plurality of recording pixel densities, the correcting means corrects the maximum image density of a higher recording pixel density.
Claim 18
Dependent Claim
32 words
The image forming apparatus of claim 1, wherein the correcting means corrects either when a power supply of the apparatus turns on or while a prescribed number of image formation is conducted.
References Cited (Backward Citations)
US4864326A
Cited
DE3618031A1
Cited
EP0624025A2
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FR2659269A1
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US5239313A
Cited
EP0679016A2
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