Abstract: An image forming apparatus including a developing unit for stocking a developing agent containing toner and forming a toner image on a photosensitive medium with the developing agent, a toner supply unit for supplying the toner to the developing unit, a toner specific concentration detecting unit for detecting the toner specific concentration of the developing agent stocked in the developing unit, a humidity detecting unit for detecting humidity in the neighborhood of the developing unit, a storage unit for storing the humidity information detected by the humidity detecting unit, and a toner specific concentration correcting unit for controlling the toner supply amount of the toner supply unit on the basis of the humidity information stored to correct the toner specific concentration, wherein the toner specific concentration correcting unit compares newly-detected humidity with reference humidity corresponding to the humidity which is detected at the time when the developing agent is stocked into the developi

Abstract: A photosensitive body for electrophotographical use has a conductive base body and a marking area provided thereon. The maximum surface roughness of a photosensitive layer provided right on the marking area is specified not to exceed 2.5 &mgr;m. And also, a ratio of the optical reflective index of the marking area to the optical reflective index of the non-marking area is specified to be in a range of 0.3 to 0.7. In this manner, even when the photosensitive layer is thin (not exceeding 25 &mgr;m), it is possible to prevent problems such as inadequate cleaning and toner falling. Hence, it is possible to offer a photosensitive body for electrophotographical use which can constantly produce high quality copied images.

Abstract: Developing devices are provided adjacent to a light sensitive element. An intermediate transfer drum is provided adjacent to the light sensitive elements. After exposure of the light sensitive element, a first color or third color image is formed on the light sensitive element. On the other hand, after exposure of the light sensitive element, a second color or fourth color image can be formed on the light sensitive element. The first color image is transferred from the transfer unit to the intermediate transfer drum at the first transfer portion, and the second color image is transferred from the transfer unit at the second transfer portion so as to be superimposed on the first color image. Similarly, the third color image is transferred so as to be superimposed on the second image and the fourth color image is transferred so as to be superimposed on the third color image to the intermediate transfer drum. Accordingly, the first to fourth color images are superimposed.

Abstract: An object of the present invention is to obtain, in an accurate and stable manner, an image density at a tone rise point in a low-density region in order to form a stable image.

Abstract: A high density detecting toner pattern is formed on a photosensitive body and a high density correction is effected by comparing a value detected by a reflection sensor with a high density reference value so as to maintain an image density at a specific level. An image density correcting section adopts a result of the preceding high density correction as the high density reference value, and compares the same with a result of a current high density correction. The image density correcting section effects the half-tone density correction only when a difference reaches or exceeds a preset difference reference value by forming a half-tone density detecting toner pattern on the photosensitive body and comparing a value detected by the reflection sensor with a half-tone reference value. Consequently, it has become possible to provide an image forming apparatus which can maintain a density output of an entire image at a specific level for any kind of images including solid, line, and half-tone, etc.

Abstract: A photosensitive body for electrophotographical use has a conductive base body and a marking area provided thereon. The maximum surface roughness of a photosensitive layer provided right on the marking area is specified not to exceed 2.5 &mgr;m. And also, a ratio of the optical reflective index of the marking area to the optical reflective index of the non-marking area is specified to be in a range of 0.3 to 0.7. In this manner, even when the photosensitive layer is thin (not exceeding 25 &mgr;m), it is possible to prevent problems such as inadequate cleaning and toner falling. Hence, it is possible to offer a photosensitive body for electrophotographical use which can constantly produce high quality copied images.

Abstract: A photosensitive body for electrophotographical use has a conductive base body and a marking area provided thereon. The maximum surface roughness of a photosensitive layer provided right on the marking area is specified not to exceed 2.5 &mgr;m. And also, a ratio of the optical reflective index of the marking area to the optical reflective index of the non-marking area is specified to be in a range of 0.3 to 0.7. In this manner, even when the photosensitive layer is thin (not exceeding 25 &mgr;m), it is possible to prevent problems such as inadequate cleaning and toner falling. Hence, it is possible to offer a photosensitive body for electrophotographical use which can constantly produce high quality copied images.

Abstract: A developing device having a reduced size in the horizontal direction and in which a developing agent is transported with stirring along a circulating route inside a developing tank to effectively mix newly added toner therewith and stir the mixture. A developing tank for storing developing agent therein is horizontally divided with a partition member thereby providing an upper chamber and a lower chamber. A developer roller and a stirring roller are disposed in the lower chamber. Two screw rollers are disposed in the upper chamber. An inlet opening is formed between an end of the partition member and a regulating member for restricting a layer if the developing agent adsorbed to the developing roller. A developing agent removed by the restricting member is fed through an inlet opening to the screw rollers in the upper chamber. The developing agent is mixed with fresh toner supplied through a supply inlet and transported with being stirred by the screw roller in its axial direction.

Abstract: A photosensitive body for electrophotographical use has a conductive base body and a marking area provided thereon. The maximum surface roughness of a photosensitive layer provided right on the marking area is specified not to exceed 2.5 .mu.m. And also, a ratio of the optical reflective index of the marking area to the optical reflective index of the non-marking area is specified to be in a range of 0.3 to 0.7. In this manner, even when the photosensitive layer is thin (not exceeding 25 .mu.m), it is possible to prevent problems such as inadequate cleaning and toner falling. Hence, it is possible to offer a photosensitive body for electrophotographical use which can constantly produce high quality copied images.

Abstract: A test patch image is formed and the density thereof is detected to maintain the image quality at a constant level. One of the image forming conditions, for example, the developing bias voltage of the developing unit inside the image forming apparatus that serves as a density controller, and is controlled in accordance with the detection result. Here, a humidity sensor for detecting the environmental change, that is, the humidity, is provided inside the apparatus, and the reference value of the toner mixing ratio is changed and corrected while the developing unit is operating when the humidity sensor detects a change in humidity. However, the toner mixing ratio is maintained and neither changed nor corrected when the density of the test patch image remains at the same level, so that the developing bias voltage is not corrected.

Abstract: Developing devices are provided adjacent to a light sensitive element. An intermediate transfer drum is provided adjacent to the light sensitive elements. After exposure of the light sensitive element, a first color or third color image is formed on the light sensitive element. On the other hand, after exposure of the light sensitive element, a second color or fourth color image can be formed on the light sensitive element. The first color image is transferred from the transfer unit to the intermediate transfer drum at the first transfer portion, and the second color image is transferred from the transfer unit at the second transfer portion so as to be superimposed on the first color image. Similarly, the third color image is transferred so as to be superimposed on the second image and the fourth color image is transferred so as to be superimposed on the third color image to the intermediate transfer drum. Accordingly, the first to fourth color images are superimposed.

Abstract: A photosensitive body for electrophotographical use has a conductive base body and a marking area provided thereon. The maximum surface roughness of a photosensitive layer provided right on the marking area is specified not to exceed 2.5 .mu.m. And also, a ratio of the optical reflective index of the marking area to the optical reflective index of the non-marking area is specified to be in a range of 0.3 to 0.7. In this manner, even when the photosensitive layer is thin (not exceeding 25 .mu.m), it is possible to prevent problems such as inadequate cleaning and toner falling. Hence, it is possible to offer a photosensitive body for electrophotographical use which can constantly produce high quality copied images.

Abstract: An image forming apparatus is designed to compensate for voltage to be applied to an exposure lamp and a charger in accordance with changes in the density of a toner image formed on a photoreceptor that occur from its initial state to its final state after an image forming operation. More specifically, the density of a reference toner image is measured by a toner-density sensor. The amount of change in the density is measured beginning with its initial state by a subtracter, and the amount of compensation for the voltage required for obtaining the optimum image quality is found. By using these amounts of compensation as teaching data, learning is made as to the relationship between the amount of change in the density and the amount of compensation in a neurocomputer. Upon forming an image, the neurocomputer executes operations in accordance with the contents of the learning based on an inputted amount of change in density, and finds an appropriate amount of compensation.

Abstract: A color balance adjusting apparatus is used for a full color copier in which an original image is illuminated by a light source; the illuminated image is exposed onto a photoreceptor to form electrostatic latent images corresponding to first, second and third colors for creating a color image; and each of the formed electrostatic latent images is developed into a visualized toner image. The color balance adjusting apparatus includes an infrared sensor for detecting toner density of the toner image formed with a toner having any one color of the first, second and third colors. The apparatus further includes automatic adjustment means which determines a relation of light intensity to toner density detected for one color by varying light intensity of said light source, and which determines optimal light intensity for the other two colors as predetermined functions of obtained optimal light intensity.

Abstract: The present invention provides a compact electrophotographic device in which the gap between a screen and a photosensitive body can be kept uniform throughout the screen, no fogging is caused on a copied imaged, no wasteful space is around the photosensitive body, color contaminations are completely prevented and the quality of a color copied image is improved.

Abstract: An electrophotographic image forming apparatus for transferring a visible toner image formed on a photoconductive body onto an intermediate transfer body primarily and transferring the toner image transferred on the intermediate body onto a paper secondarily is disclosed. In the electrophotographic image forming apparatus, the toner remaining on the photoconductive body is removed by a first cleaner blade after the primary transfer, and the toner remaining on the intermediate transfer body is removed by a second cleaner blade after the secondary transfer. A contact pressure of the second cleaner blade to be applied to the intermediate transfer body is set to be larger than a contact pressure of the first cleaner blade to be applied to the photoconductive body.

Abstract: An image adjusting apparatus being provided in a copying machine capable of performing a copy of an original by using a photosensitive body in two or more copying modes, includes a unit for sensing a toner density of an image formed on the photosensitive body, a unit for deriving a function in accordance with each of the two or more copying modes if a control voltage influencing the toner density is changed, and a unit for setting the control voltage to be a voltage value obtained based on a predetermined reference toner density and the function derived by the deriving unit. The function stands for a relation between the changed control voltage and the toner density sensed by the sensing unit.

Abstract: A full color copying machine which includes intermediate transfer medium whereon toner images having respective color components, formed on a photoreceptor are transferred to form one color toner image, and a screen filter disposed so as to be freely inserted or removed in or from a path of exposure light, which filters the exposure light for exposing the photoreceptor into a pattern of lines. A plurality of color toner images obtained by executing a plurality of copying processes based on a plurality of exposures applied to an original document are superposed on the intermediate transfer medium to form a color toner image. The copying machine further includes a screen mode for inserting a screen filter into a path of exposure light and a normal mode for removing the screen filter from the path of exposure light.

Abstract: An image density correcting device for a color copying machine capable of producing monochrome copies and full color copies, the device including a toner density detecting means for detecting the toner density of a toner image transferred on a transfer medium; a toner density storing means for storing a predetermined reference value for the toner density; a toner density comparing/judging means for judging the toner density of the image by comparing the toner density detected by the toner density detecting means with the toner density reference value stored in the toner density storing means; and a toner density correcting means for correcting the toner density of the image based on the result of the comparison and judgment by the comparing/judging means, wherein the toner density is corrected after a black toner layer is formed in any non-black color detectable by the toner density detecting means, of areas where black toner layers are formed for monochrome copying with black toner.

Abstract: A transfer unit including: a transfer belt onto which toner images are formed; a backup roller on which said transfer belt is applied, the metallic surface of said backup roller being coated with a dielectric film; a metallic transfer roller that is disposed opposite to said backup roller across said transfer belt and to which a predetermined transfer voltage is applied, said transfer roller pressing copy paper against said backup roller with said transfer belt placed therebetween so that said toner images formed on said transfer belt are transferred onto said copy paper to be transported between said transfer roller and said transfer belt; and a back plate that is located in the vicinity of said backup roller and that contacts the back surface of said transfer belt, whereby an electric field for transferring a toner image by a low transfer voltage can be created, thereby preventing the transfer belt from dielectric breakdown.