Abstract: There is disclosed an ink jet recording apparatus which comprises a pit-in ink supply mechanism for interconnecting a main tank and a subtank to be communicated with/separated from each other, and supplying an ink from the subtank to a recording head. In this constitution, an ink residual amount V in the subtank during recording or at the end of recording is selected to be V>v/b in which V is the ink residual amount in the subtank during recording or after the end of recording, b(1>b>0) is a nonvolatile component ratio of the ink,and v is a volume of a liquid chamber of the recording head.

Abstract: High image quality is maintained even on front and rear ends of a printing medium where deterioration in the image quality is more likely to occur due to reduction in conveyance accuracy of the printing medium. In printing on the front and rear ends, the printing medium being not supported by both conveying means respectively placed upstream and downstream of a printing point in a printing medium conveying direction, a print swath of a printing head and the amount of conveying a printing medium are reduced. Moreover, the reducing print swath and the reducing conveyance amount are designed to be decreased in the cases of selecting a printing medium for high-quality printing as well as a monochrome print mode where image distortion caused by deviation of ink-landing positions is more noticeable due to a small number of colors of ink to be used and low coverage thereof.

Abstract: A stable image may not be obtained due to condensation of an ink left in a subtank. According to the present invention, a stable image is always obtained by changing a method for supplying an ink from a main tank to the subtank in accordance with an elapsed time from the end of previous printing.

Abstract: An ink-jet printing apparatus according to the present invention has a main tank storing ink, a sub-tank releasably connectable with the main tank through an ink supply passage and a printing head for ejecting ink supplied from the sub-tank, for performing printing by ejecting ink from the printing head to a printing medium. The apparatus includes an ink supply controller for supplying ink from the main tank to the sub-tank through the ink supply passage during a period after completion of printing at a preceding time and before starting printing at a next time, and an ink draining controller for performing ink draining of at least a part of ink remaining in the sub-tank during the period after completion of printing at the preceding time and before starting printing at the next time and in advance of ink supply by the ink supply controller.

Abstract: An ink jet printing apparatus and an ink jet printing method according to the present invention suppress a variation in the density of ink in a supply channel and a print head without the need for useless recovery operations, thus always providing very reliable high-grade images. The ink jet printing apparatus carries out printing using a print head for ejecting ink. The apparatus includes a scanning unit for causing the print head to scan across a printing medium, a measuring unit for measuring a time from an end of a preceding printing operation until a start of a current printing operation, and a determining unit for determining whether or not a result of measurement executed by the measuring unit exceeds a predetermined value. The scanning unit causes the print head to carry out at least one idle scan before the start of a printing operation depending on a result of determination made by the determining unit.

Abstract: In the ink jet recording apparatus using an on-demand supply system, an image natural and stable in color tone is output. For this purpose, when a capacity of a sub-tank is represented by A, an amount of residual ink remaining after the ink has been discharged is represented by “a”, a ratio by weight of a volatile component in a composition of ink used is represented by B and a ratio of a colorant concentration of ink at saturated state made by repeating ink supply and ink discharge, to an initial colorant concentration of the ink is represented by R, they are satisfying an equation of A/(A?a×B)=R?1.20.

Abstract: There is disclosed an ink jet recording apparatus which comprises a pit-in ink supply mechanism for interconnecting a main tank and a subtank to be communicated with/separated from each other, and supplying an ink from the subtank to a recording head. In this constitution, an ink residual amount V in the subtank during recording or at the end of recording is selected to be V>v/b in which V is the ink residual amount in the subtank during recording or after the end of recording, b (1>b>0) is a nonvolatile component ratio of the ink, and v is a volume of a liquid chamber of recording means.

Abstract: A stable image may not be obtained due to condensation of an ink left in a subtank. According to the present invention, a stable image is always obtained by changing a method for supplying an ink from a main tank to the subtank in accordance with an elapsed time from the end of previous printing.

Abstract: In the ink jet recording apparatus using an on-demand supply system, an image natural and stable in color tone is output. For this purpose, when a capacity of a sub-tank is represented by A, an amount of residual ink remaining after the ink has been discharged is represented by “a”, a ratio by weight of a volatile component in a composition of ink used is represented by B and a ratio of a colorant concentration of ink at saturated state made by repeating ink supply and ink discharge, to an initial colorant concentration of the ink is represented by R, they are satisfying an equation of A/(A−a×B)=R≦1.20.

Abstract: An ink-jet printing apparatus according to the present invention has a main tank storing ink, a sub-tank releasably connectable with the main tank through an ink supply passage and a printing head for ejecting ink supplied from the sub-tank, for performing printing by ejecting ink from the printing head to a printing medium. The apparatus includes ink supply controller for supplying ink from the main tank to the sub-tank through the ink supply passage during a period after completion of printing at preceding time and before starting printing at next time, and ink draining controller for performing ink draining at least a part of ink remaining in the sub-tank during the period after completion of printing at preceding time and before starting printing at next time and in advance of ink supply by the ink supply controller.

Abstract: An ink jet printing apparatus and an ink jet printing method according to the present invention suppress a variation in the density of ink in a supply channel and a print head without the needs for useless recovery operations, thus always providing very reliable high-grade images. The ink jet printing apparatus carries out printing using a print head for ejecting ink. The apparatus includes scanning means for causing the print head to scan a printing medium, measuring means for measuring time from an end of a preceding printing operation till a start of a current printing operation, and determining means for determining whether or not a result of measurement executed by the measuring means exceeds a predetermined value. The scanning means causes the print head to carry out idle scan before the start of a printing operation depending on a result of determination made by the determining means.

Abstract: Digital image data corresponding to an original read in by a CCD is stored in a page memory in pixel units, and a CPU reads the stored image data and creates a histogram. For an original having many high-density portions, an image is formed using a LOG conversion table which generates density data that enables reproduction of the tonality of the high-density portions. For an original which is comparatively faint, an image is formed using a LOG conversion table which generates density data that assures tone reproduction up to the maximum density of the original even if high-density portions cannot be reproduced. As a result, tone reproduction suited to the original image can be realized at all times.

Abstract: A method of fabricating a developer bearing body includes the steps of preparing metallic base material blasting the surface of the metallic base material using spherical particles and plating the surface of the metallic base material blasted, wherein a thickness of the plating layer is two or more times as large as a particle diameter in volume average of the developer.

Abstract: A developing device has a developing container containing a toner therein, and a toner carrying member provided in the opening portion of the developing container and rotatable with the toner carried thereon. The difference between the work function of the surface of the toner carrying member and the work function of the toner is greater than 0.1 and smaller than 1.0.

Abstract: The present invention aims to improve image quality in an image forming apparatus in which plural color toner images are formed on a photosensitive member and the toner images are collectively transferred onto a transfer material, and provides such an image forming apparatus that includes a first charge member for charging the photosensitive member, a digital optical system for exposing image information on the photosensitive member, a first developing device for inversion-developing a first latent image formed on the photosensitive member with first toner, a second charge member for charging the photosensitive member developed by the first developing member, a second developing member for developing a second latent image formed on the photosensitive member by exposing second image information onto the charged photosensitive member, with second toner, and a transfer means for collectively transferring first and second toner images formed on the photosensitive member onto a transfer material, and wherein an ex

Abstract: A developing method includes the steps of: applying for a predetermined duration t.sub.1 to a developer carrying member, faced to an image bearing member for bearing an electrostatic image before formation of a developed image, for carrying a developer, a back-transfer voltage V.sub.1 for returning the developer to the developer carrying member; applying for a predetermined duration t.sub.2 to the developer carrying member a transfer voltage V.sub.2 for transferring the developer from the developer carrying member to the image bearing member; shifting from the back-transfer voltage V.sub.1 to the transfer voltage V.sub.2 substantially in rectangular profile; and shifting from the transfer voltage V.sub.2 to the back-transfer voltage V.sub.1, taking a predetermined duration t.sub.3.

Abstract: A developing apparatus includes a developer carrying member for carrying a magnetic developer. The developer carrying member is provided with a plurality of magnetic poles. The apparatus also includes a regulating member for regulating the layer thickness of the developer on the developer carrying member, and an elastic rotatable member, disposed upstream of a developer regulating position of the regulating member with respect to a movement direction of the developer carrying member, for supplying the magnetic developer onto the developer carrying member. A surface of the elastic rotatable member is composed of unicellular foamed material.

Abstract: An image forming method includes forming a first electrostatic image on an image bearing member; developing with developer carried on a developer carrying member the first image formed in the first image forming step; forming a second electrostatic image on the image bearing member carrying the first developed image formed in the first developing step; and developing with developer carried on a developer carrying member, the electrostatic image formed in the second electrostatic image forming step; wherein during the second developing step, an alternating electric field is generated between the developer carrying member and the image bearing member, and a time period T(1-2) necessary for the electric field to shift from a peak value V1 of a transfer portion, which transfers developer to the image bearing member, to a peak value V2 of a back-transfer portion, which transfers developer back from the image bearing member to the developer carrying member, is larger than a time period T(2-1) necessary for the elec

Abstract: When forming an image in which a half-tone image area such as photograph, screen, or the like and characters and fine lines exist the half-tone image area and the character and fine line portion are stably reproduced without deteriorating the picture qualities of both of them and, particularly, the character and fine line portion can be clearly reproduced. A digital image signal generated from an image reader is stored into an image memory on a pixel unit basis. A CPU subsequently reads the stored digital image signal and forms a frequency distribution function (density histogram) as a detection frequency of corresponding density values every pixel. The density level value of the portion in which the detection frequency is locally high is detected from the formed density histogram. The density level values are converted into at least one density value by a gradation correction circuit.

Abstract: An image forming apparatus has a producing device for producing density information from an original image signal, an image forming device for effecting image formation, and a controlling device for controlling an image formation condition based on the density information of the producing device and the image formation density of the image forming device. The density information is obtained as a frequency distribution of output level of the producing device.