Abstract: According to an aspect of the invention, a developing device includes a developing container that accommodates a two-component developer, a toner concentration detecting unit that detects a toner concentration of the developer by a detecting unit exposed to an inner wall of the developing container, a transport member that is disposed within the developing container and stirs and transport the developer with a transport blade having a pitch that is equal to or less than a size of the detecting unit of the toner concentration detecting unit, and a plurality of gap holding members that is provided at a position facing the toner concentration detecting unit of the transport member and holds a gap such that a tip thereof is abutted against the inner wall of the developing container.

Abstract: An image forming apparatus includes a first condition section that derives, from the density of the image detected by an image density detector, a forming condition in forming an image such that the density of the image formed comes close to a predetermined target density, a second condition section that derives, from the environmental state detected by the environmental detector, a forming condition such that the density of the formed image becomes the target density, and a stabilization section that causes, when a difference between the two forming conditions exceeds a predetermined degree, the image forming section to perform a stabilization operation which stabilizes a developing property of the developer in the developing device as compared to the current environmental state, and thereafter causes the formation of an image, the density detection, and the derivation of the forming condition by the first condition section to be performed again.

Abstract: An image forming apparatus includes a first condition section that derives, from the density of the image detected by an image density detector, a forming condition in forming an image such that the density of the image formed comes close to a predetermined target density, a second condition section that derives, from the environmental state detected by the environmental detector, a forming condition such that the density of the formed image becomes the target density, and a stabilization section that causes, when a difference between the two forming conditions exceeds a predetermined degree, the image forming section to perform a stabilization operation which stabilizes a developing property of the developer in the developing device as compared to the current environmental state, and thereafter causes the formation of an image, the density detection, and the derivation of the forming condition by the first condition section to be performed again.

Abstract: According to an aspect of the invention, a developing device includes a developing container that accommodates a two-component developer, a toner concentration detecting unit that detects a toner concentration of the developer by a detecting unit exposed to an inner wall of the developing container, a transport member that is disposed within the developing container and stirs and transport the developer with a transport blade having a pitch that is equal to or less than a size of the detecting unit of the toner concentration detecting unit, and a plurality of gap holding members that is provided at a position facing the toner concentration detecting unit of the transport member and holds a gap such that a tip thereof is abutted against the inner wall of the developing container.

Abstract: A density detection apparatus includes the following elements. An image forming unit forms density detection images having different area ratios. A measuring unit measures an amount of reflected light. A storage unit stores reference values and also stores a representative value thereof. A determining unit determines a threshold for the area ratios of the density detection images on the basis of a variation among the reference values. A density obtaining unit obtains, for a density detection image having an area ratio which exceeds the threshold, a density level by using the amount of light reflected by the density detection image and the representative value, and obtains, for a density detection image having an area ratio which is equal to or smaller than the threshold, a density level by using the amount of light reflected by the density detection image, the associated reference value, and the representative value.

Abstract: An image forming apparatus includes an image carrier, and a rotation device having image-forming devices each containing a toner and forming a toner image on the image carrier with the toner. The apparatus further includes: a detector attached to at least one of the image-forming devices to detect a quantity of the toner, thereby outputting an analog signal representing the quantity; and a transmission path transmitting the analog signal to the outside of the rotation device. The transmission path includes: a rotation terminal mounted on and rotating with the rotation device; and a contact terminal provided outside the rotation device, and maintaining continuity with the rotation terminal by contacting a surface of the rotation terminal even when the rotation terminal rotates. The apparatus further includes a correction section correcting the analog signal transmitted by the transmission path, according to a contact resistance between the rotation terminal and the contact terminal.

Abstract: An image forming apparatus includes a controller that provides control in which, if image formation processing by a single unit is executed first since a density adjustment condition for adjusting a density of an image is satisfied, a density adjustment value is changed by a predetermined basic change amount, and a first image is formed in a corresponding image formed region with a density that is adjusted in accordance with the changed density adjustment value, and control in which, if a single image other than the first image is formed in the corresponding image formed region, the current density adjustment value is changed by a predetermined fine change amount that is smaller than the basic change amount, and the single image is formed in the corresponding image formed region with a density that is adjusted in accordance with the changed density adjustment value.

Abstract: A density detection apparatus includes the following elements. A storage unit stores therein image information. A measuring unit measures amounts of light components reflected by an image carrier or density detection images represented by the image information. A light amount obtaining unit obtains a variation in amounts of light components reflected by each region in which the associated density detection image is formed, and obtains, as a reference value, a representative value of the amounts of light components. An image correcting unit corrects the image information by changing an arrangement order of the density detection images. An image forming unit forms the density detection images on the image carrier on the basis of the corrected image information. A density obtaining unit obtains density levels of density detection images corresponding to their area ratios by using the amounts of light components reflected by the density detection images and the reference values.

Abstract: An image forming apparatus includes: an image carrier; an image-forming device including a toner and forming a toner image on the image carrier during a first running period; a detector detecting a toner quantity in a set period within the first running period; and a toner supplying device supplying the image-forming device with a toner according to the detected toner quantity. The apparatus further includes a period setting device that causes the image-forming device to stir the toner over a second running duration longer than the first running duration, and causes, during the second running duration, the detector to perform detection plural times over a period longer than the period, thereby measuring a result stable time required to stabilize the result of the detection, and setting in the detector, as the period, a period over which the result of the detection is stable within the first running duration.

Abstract: A density detection apparatus includes the following elements. A storage unit stores therein image information. A measuring unit measures amounts of light components reflected by an image carrier or density detection images represented by the image information. A light amount obtaining unit obtains a variation in amounts of light components reflected by each region in which the associated density detection image is formed, and obtains, as a reference value, a representative value of the amounts of light components. An image correcting unit corrects the image information by changing an arrangement order of the density detection images. An image forming unit forms the density detection images on the image carrier on the basis of the corrected image information. A density obtaining unit obtains density levels of density detection images corresponding to their area ratios by using the amounts of light components reflected by the density detection images and the reference values.

Abstract: An image forming apparatus includes a controller that provides control in which, if image formation processing by a single unit is executed first since a density adjustment condition for adjusting a density of an image is satisfied, a density adjustment value is changed by a predetermined basic change amount, and a first image is formed in a corresponding image formed region with a density that is adjusted in accordance with the changed density adjustment value, and control in which, if a single image other than the first image is formed in the corresponding image formed region, the current density adjustment value is changed by a predetermined fine change amount that is smaller than the basic change amount, and the single image is formed in the corresponding image formed region with a density that is adjusted in accordance with the changed density adjustment value.

Abstract: A density detection apparatus includes the following elements. An image forming unit forms density detection images having different area ratios. A measuring unit measures an amount of reflected light. A storage unit stores reference values and also stores a representative value thereof. A determining unit determines a threshold for the area ratios of the density detection images on the basis of a variation among the reference values. A density obtaining unit obtains, for a density detection image having an area ratio which exceeds the threshold, a density level by using the amount of light reflected by the density detection image and the representative value, and obtains, for a density detection image having an area ratio which is equal to or smaller than the threshold, a density level by using the amount of light reflected by the density detection image, the associated reference value, and the representative value.

Abstract: An image forming apparatus includes: an image carrier; an image-forming device including a toner and forming a toner image on the image carrier during a first running period; a detector detecting a toner quantity in a set period within the first running period; and a toner supplying device supplying the image-forming device with a toner according to the detected toner quantity. The apparatus further includes a period setting device that causes the image-forming device to stir the toner over a second running duration longer than the first running duration, and causes, during the second running duration, the detector to perform detection plural times over a period longer than the period, thereby measuring a result stable time required to stabilize the result of the detection, and setting in the detector, as the period, a period over which the result of the detection is stable within the first running duration.

Abstract: An image forming apparatus includes an image carrier, and a rotation device having image-forming devices each containing a toner and forming a toner image on the image carrier with the toner. The apparatus further includes: a detector attached to at least one of the image-forming devices to detect a quantity of the toner, thereby outputting an analog signal representing the quantity; and a transmission path transmitting the analog signal to the outside of the rotation device. The transmission path includes: a rotation terminal mounted on and rotating with the rotation device; and a contact terminal provided outside the rotation device, and maintaining continuity with the rotation terminal by contacting a surface of the rotation terminal even when the rotation terminal rotates. The apparatus further includes a correction section correcting the analog signal transmitted by the transmission path, according to a contact resistance between the rotation terminal and the contact terminal.