Abstract: An exposure device irradiates a photoconductor with light on the basis of an exposure signal and thereby forms an electrostatic latent image. A toner amount calculating unit (a) determines a distribution pattern of the electrostatic latent image on the basis of the exposure signal, (b) determines an electric field variation level of a target pixel, (c) determines an electric field intensity of the target pixel on the basis of a value of the target pixel in the distribution pattern and the electric field variation level, and (d) determines a toner consumption amount corresponding to the electric field intensity. Further, the toner amount calculating unit limits the electric field variation level to an uppermost value or less, the uppermost value corresponding to a value of the target pixel in the distribution pattern of the electrostatic latent image.

Abstract: An edge emphasis amount determining unit performs a spatial filter process and thereby determines an edge emphasis amount corresponding to edge effect. A first toner counter (a) counts a toner consumption amount including the edge emphasis amount for a non-block-edge pixel in a block as a unit of image processing, and (b) counts a toner consumption amount not including the edge emphasis amount for a block edge pixel in the block. A second toner counter counts a toner consumption amount not including the edge emphasis amount for the non-block-edge pixel and the block edge pixel. A toner consumption amount calculating unit calculates a toner consumption amount of the block on the basis of a difference between a toner counting value of the first toner counter and a toner counting value of the second toner counter.

Abstract: A base toner amount determining unit is configured to determine a base toner amount without taking edge effect into account, the base toner amount corresponding to a pixel value of image data for which gradation correction has not been performed. A laser profile applying unit is configured to perform for the base toner amount a first spatial filter process corresponding to a laser profile of an exposure device. An edge emphasis amount determining unit is configured to perform a second spatial filter process for the base toner amount before the first spatial filter process or after the first spatial filter process and thereby determine an edge emphasis amount corresponding to the edge effect. A toner counter is configured to count as a toner consumption amount a sum of the base toner amount after the first spatial filter process and the edge emphasis amount.

Abstract: An exposure device irradiates a photoconductor with light on the basis of an exposure signal and thereby forms an electrostatic latent image. A toner amount calculating unit (a) determines a distribution pattern of the electrostatic latent image on the basis of the exposure signal, (b) determines an electric field variation level of a target pixel, (c) determines an electric field intensity of the target pixel on the basis of a value of the target pixel in the distribution pattern and the electric field variation level, and (d) determines a toner consumption amount corresponding to the electric field intensity. Further, using spatial filters independently of each other in a primary scanning direction and in a secondary scanning direction, the toner amount calculating unit determines the electric field variation level on the basis of (a) the distribution pattern or (b) the exposure signal.

Abstract: A base toner amount is determined without taking edge effect into account. The base toner amount corresponds to a pixel value of image data for which gradation correction has not been performed. For the base toner amount, a first spatial filter process is performed corresponding to a laser profile of the exposure device. A second spatial filter process is performed for the base toner amount before or after the first spatial filter process and thereby an edge emphasis amount is determined corresponding to the edge effect. A toner counter counts as a toner consumption amount a sum of the base toner amount after the first spatial filter process and the edge emphasis amount. Further, a gain control unit multiplies the edge emphasis amount by a coefficient corresponding to the base toner amount after the first spatial filter process and thereby controls a gain of the edge emphasis amount.

Abstract: An image forming apparatus includes a printing device, an output value converting unit, and a controller. The output value converting unit is configured to (a) change pixel values of pixels alternatively determined in a primary scanning direction and a secondary scanning direction so as to delete a dot on the pixels in a solid part in a target image and (b) change pixel values of pixels that are alternatively not determined in the primary scanning direction and the secondary scanning direction so as to gain a dot size of the pixels in the solid part. The controller is configured to control the printing device so as to print the solid part with dot sizes corresponding to the pixel values.

Abstract: An inkjet recording apparatus includes a piezoelectric element, an extraction processing portion, and a drive control portion. The piezoelectric element is provided in correspondence with a nozzle, and upon input of a first drive signal, causes ink to be ejected from the nozzle. The extraction processing portion, when a print process is executed, extracts a non-ejection period during which a non-ejection state continues for more than a reference time period, from an execution period of the print process based on image data printed in the print process, wherein ink is not ejected from the nozzle in the non-ejection state. The drive control portion inputs a second drive signal for causing the piezoelectric element to stir the ink in the nozzle, to the piezoelectric element during a partial period of the non-ejection period extracted by the extraction processing portion.

Abstract: A sheet conveyance device includes a shape detecting portion, and a switch control portion. The shape detecting portion detects a shape of a sheet at a detection position between a first conveyance member and a second conveyance member. The switch control portion, when a front end of the sheet has passed a arrangement position at which the first conveyance member is arranged, switches an detection interval at which the shape of the sheet is detected by the shape detecting portion, to a first interval that corresponds to a rotation speed of the first conveyance member, and when a rear end of the sheet has passed the arrangement position, switches the detection interval to a second interval that corresponds to the rotation speed of the second conveyance member.

Abstract: A sheet conveyance device includes a shape detecting portion, and a switch control portion. The shape detecting portion detects a shape of a sheet at a detection position located between a first conveyance member and an image forming position in a sheet conveyance path. The switch control portion, when the first conveyance member is determined to be in an accelerated state where it is accelerated from a stopped state to a driven state, switches an detection interval at which the shape of the sheet is detected by the shape detecting portion, to a first interval that corresponds to a rotation speed of the first conveyance member, and when the first conveyance member is determined to be in a decelerated state where it is decelerated from the driven state to the stopped state, switches the detection interval to a predetermined second interval.

Abstract: An inkjet recording apparatus includes a piezoelectric element, an extraction processing portion, and a drive control portion. The piezoelectric element is provided in correspondence with a nozzle, and upon input of a first drive signal, causes ink to be ejected from the nozzle. The extraction processing portion, when a print process is executed, extracts a non-ejection period during which a non-ejection state continues for more than a reference time period, from an execution period of the print process based on a plurality of pieces of image data printed in the print process, wherein ink is not ejected from the nozzle in the non-ejection state. The drive control portion inputs a second drive signal for causing the piezoelectric element to stir the ink in the nozzle, to the piezoelectric element during a partial period of the non-ejection period extracted by the extraction processing portion.

Abstract: An inkjet recording apparatus includes a piezoelectric element, an extraction processing portion, and a drive control portion. The piezoelectric element is provided in correspondence with a nozzle, and upon input of a first drive signal, causes ink to be ejected from the nozzle. The extraction processing portion, when a print process is executed, extracts a non-ejection period during which a non-ejection state continues for more than a reference time period, from an execution period of the print process based on image data printed in the print process, wherein ink is not ejected from the nozzle in the non-ejection state. The drive control portion inputs a second drive signal for causing the piezoelectric element to stir the ink in the nozzle, to the piezoelectric element during a partial period of the non-ejection period extracted by the extraction processing portion.

Abstract: In an input image generated as a binary image from a scanned document image, a projection image generating unit (a) tries at each primary-scanning-directional target pixel position to detect a secondary-scanning-directional run along a secondary scanning direction, projects the detected secondary-scanning-directional run at the primary-scanning-directional target pixel position and thereby generates a one-dimensional primary-scanning-directional-projection image, and (b) tries at each secondary-scanning-directional target pixel position to detect a primary-scanning-directional run along the primary scanning direction, projects the detected primary-scanning-directional run at the secondary-scanning-directional target pixel position and thereby generates a one-dimensional secondary-scanning-directional-projection image.

Abstract: An image reading apparatus reads an image on a document surface. The image reading apparatus includes a document-supporting unit, a light source, and an image reading unit. The document-supporting unit supports the document and transmits light. The light source, from a direction inclined with respect to a line perpendicular to the document surface, irradiates the document surface with an irradiation beam transmitted through the document-supporting unit. The image reading unit reads the image in accordance with light reflected from the document surface and thereby generates image data. The document-supporting unit enables varying degree that the irradiation beam scatters in passing through the document-supporting unit.

Abstract: A filter processing unit performs a bandpass filter process for a difference between an output pixel value and an input pixel value of an adjacent pixel to a target pixel. An error diffusion unit performs an error diffusion process of a quantization error for output of the filter processing unit. A quantizer performs quantization for a value obtained by the error diffusion process and thereby determines the output pixel value of the target pixel. The bandpass filter process is performed with characteristics different from each other (a) in respective ones of a primary scanning direction and a secondary scanning direction and (b) for respective ones of the component colors of the image. Furthermore, a filter coefficient of the bandpass filter process independently for each component color of an image is corrected for banding reduction with a correction coefficient corresponding to an angle from the primary scanning direction.

Abstract: An offset calculating unit (2) performs an offset process for a luma plane and/or chroma planes where the offset process compresses a pixel value range by a predetermined offset except for a saturation value. A compression processing unit (3) performs a lossy compression process using frequency conversion for the luma plane and the chroma planes after the offset process performed by the offset calculating unit (2). Further, a decompression processing unit (4) decompresses compressed data generated in the compression process performed by the compression processing unit (3) to a luma plane and chroma planes. An inverse offset calculating unit (5) performs an inverse offset process for a plane for which the offset process has been performed among the luma plane and the chroma planes after decompression by the decompression processing unit (4) where the inverse offset process expands a pixel value range by the offset.

Abstract: A filter processing unit performs a bandpass filter process for a difference between an output pixel value and an input pixel value of an adjacent pixel to a target pixel. An error diffusion unit performs an error diffusion process of a quantization error for output of the filter processing unit. A quantizer performs quantization for a value obtained by the error diffusion process and thereby determines the output pixel value of the target pixel. The bandpass filter process is performed with characteristics different from each other (a) in respective ones of a primary scanning direction and a secondary scanning direction and (b) for respective ones of the component colors of the image. Furthermore, a filter coefficient of the bandpass filter process independently for each component color of an image is corrected for banding reduction with a correction coefficient corresponding to an angle from the primary scanning direction.

Abstract: A subsampling unit (2) converts pixel values of plural pixels in a pixel block in the chroma plane to one pixel value associated with the pixel block on the basis of values in the pixel block in an attribute plane that indicates existency of an edge at the predetermined resolution. A compression processing unit (3) performs a compression process for a luma plane and the chroma planes for which the subsampling has been performed by the subsampling unit (2).

Abstract: A subsampling unit (2) converts pixel values of plural pixels in a pixel block in the chroma plane to one pixel value associated with the pixel block on the basis of values in the pixel block in an attribute plane that indicates existency of an edge at the predetermined resolution. A compression processing unit (3) performs a compression process for a luma plane and the chroma planes for which the subsampling has been performed by the subsampling unit (2).

Abstract: An offset calculating unit (2) performs an offset process for a luma plane and/or chroma planes where the offset process compresses a pixel value range by a predetermined offset except for a saturation value. A compression processing unit (3) performs a lossy compression process using frequency conversion for the luma plane and the chroma planes after the offset process performed by the offset calculating unit (2). Further, a decompression processing unit (4) decompresses compressed data generated in the compression process performed by the compression processing unit (3) to a luma plane and chroma planes. An inverse offset calculating unit (5) performs an inverse offset process for a plane for which the offset process has been performed among the luma plane and the chroma planes after decompression by the decompression processing unit (4) where the inverse offset process expands a pixel value range by the offset.

Abstract: A scanner device has a first mode for reading a normal object placed on a document table and a second mode for reading a self-luminous object placed on the document table. The scanner device includes a light detecting portion and a control portion. The light detecting portion detects light from an object placed on the document table. The control portion switches the reading mode between the first mode and the second mode on the basis of a detection result of the light detecting portion. When an image sensor detects light from the object placed on the document table in the second mode, the sensitivity of the image sensor is automatically adjusted in accordance with the amount of the detected light.