Abstract: A light emitting element irradiates light upon a surface area of an intermediate transfer belt which is wound around a roller, i.e., upon a wind area, and light receiving units receive light reflected at the wind area. Based on a signal outputted from a sensor, the quantity of toner is measured. In the wind area, the intermediate transfer belt does not flap in a direction which is approximately perpendicular to a direction in which the belt travels. This suppresses a change in distance (sensing distance) between the sensor and the intermediate transfer belt.

Abstract: An image forming apparatus in which the control of toner supply can be effected well irrespective of an image forming mode (image forming speed). The density of a toner in a developer contained in a developer containing portion is detected by a toner density sensor. A controller controls the supply of the toner to the developer containing portion so that the density of the toner detected by the toner density sensor may assume a predetermined target value. When the last developing operation is executed at an ordinary speed, whereafter next developing operation is executed at a low speed, a toner image of predetermined density is formed, and the density of this toner image is detected by an image density sensor. The controller determines an amount of toner supply by the use of the target value corrected on the basis of the detection output of the image density sensor, and the detection output of the toner density sensor.

Abstract: Applying a toner print to a substrate, in particular to a substrate (3). At least one print (7) is applied to the substrate. Then, the amount of toner applied to the substrate is measured by a measuring device (21). Finally, the difference between the actual amount of toner and a desired amount of toner in the print (7) applied to the substrate is determined, the printing process being influenced on the basis of the deviation in such a way that the difference in the amounts of toner is reduced or at least remains the same during subsequent prints.

Abstract: Methods and apparatus for reducing the time required to generate a calibration image product on a transfer medium in an inline imaging device having a plurality of toner stations by simultaneously applying at least two toners to the transfer medium. In one method of the present invention, each toner station is configured to deposit an associated toner onto the transfer medium to thereby generate the calibration product. The method includes the step of depositing a first toner from a first toner station and a second toner from a second toner station onto the transfer medium while moving the transfer medium from a first position relative to the plurality of toner stations to a second position. An apparatus of the present invention includes a scanning section, a plurality of toner stations, a transfer medium, and a calibration image product generator. Each toner station is configured to deposit a dedicated toner onto the transfer medium.

Abstract: An object of the invention is to provide a toner density sensor capable of detecting toner density with high accuracy without being affected by the temperature change. A light-emitting diode emits infrared light toward the toner attached to the surface of a photosensitive drum, and the infrared light reflected from the toner is received by a photodiode. An amplifier circuit for detecting color toner density and an amplifier circuit for detecting black toner density, of which both amplify outputs from the photodiode, each employ a thermister for the feedback resistance of the amplifier. An input resistance in the amplifier circuit and the thermister adjust the gain of the amplifier circuit so as to obtain optimal outputs.

Abstract: An image forming apparatus forming a full color image by plural color materials. An image of an original is color-separated so as to form a color separation signal, and the color separation signal is converted to a color signal corresponding to each color material. The color signal is color-corrected so as to correct a color mixing state of the plural color materials, and a color image is formed by the corrected color signal. A test image of single color is formed, and a density of the test image is detected. Control is performed on a correcting condition for color-correcting the color signed based on the detected density. The correction to the color signal is delayed until toner is supplemented to the developing device.

Abstract: A method, apparatus and article of manufacture for modifying printing based upon direct on-the-fly media characteristic parameters is disclosed. The present invention on-the-fly directly measures a media characteristic parameter and performs real-time print modification in response thereto. The measured characteristic parameters include paper texture and composition, as well as adhesion and penetration of print. The modification of print in response to these measured parameters may allow a customer to maintain observed print quality with lower-cost materials. Adjustments may include the addition of coating, hot rolling, or adjustment of toner concentration. Measured parameters may include mottle, paper texture, and bleed through.

Abstract: An electrophotographic printing machine having a latent image is recorded on a photoconductive member with the latent image being developed with marking particles, includes: means for recording a test patch consisting of a solid patch; means for developing the test patch with marking particles wherein the developed patch has a solid portion and an edge portion; means for measuring a density of the solid portion of the test patch; means for measuring a density of the edge portion of the test patch; means for generating a first output signal corresponding to the density of the solid portion of the test patch; and means for generating a second output signal corresponding to the density of the edge portion of the test patch.

Abstract: A developer density controlling apparatus includes image density detecting device for detecting a target density on the basis of a detected image and, if a difference between a toner density detected by a developer density detecting device and the target density is equal to or greater than a predetermined value, the image density detecting device does not correct the target density.

Abstract: The invention relates to an electrographic printing or photocopying device and method. A toner mark (10) is provided on a photoconductive drum and printed with toner using a developing station. The toner mark (10) is scanned by a sensor at two points of measurement (a1,a2). The amount of toner in a developing mixture consisting of two components depends upon the difference (&Dgr;U) or the quotient of the amount of the signals of the sensor at both points of measurement. A device which is also disclosed enables the exact length of the toner mark (10) to be determined.

Abstract: Methods and apparatus for detecting a low toner condition in a color laser printer are disclosed. The invention generally includes at least one energy detector which can detect relative intensity of electromagnetic energy reflected from at least one toner area. A variation in the intensity of reflected energy, either from a reference value, or within a single toner area, or between two toner areas, can indicate toner fade due to a low toner condition. Apparatus in accordance with the present invention can also include a movable support surface which can support at least one toner area. Apparatus can also include at least one of various configurations of energy sources which can be configured to produce electromagnetic energy and direct the energy toward the toner area. A method in accordance with the present invention can include detecting intensity of electromagnetic energy reflected from at least one toner area.

Abstract: An image forming apparatus comprises an image bearing member, developing portion for developing by developer an electrostatic latent image formed on the image bearing member, potential detection portion for detecting the potential of the electrostatic latent image on the image bearing member for detection use, potential control portion for controlling the electrostatic latent image for detection use in accordance with the output of the potential detection portion, and density detection portion for detecting the density of a developer image for detection use. For this image forming apparatus, the density detection portion detects the density of a developer image for detection use obtained by developing by the developing portion an electrostatic latent image for detection use which is potentially controlled by the potential control portion.

Abstract: A developer supplying apparatus includes a developer container containing therein a developer provided with a toner and a carrier, a developer bearing member for magnetically bearing and carrying the developer in the developer container to develop an electrostatic latent image formed on an image bearing member, a detector for detecting information corresponding to the density of the toner, and a supplying device for supplying the toner and the carrier to the developer container in conformity with the output of the detector. The intensity of an electric field for shifting the carrier from the developer bearing member to the image bearing member is greater than the intensity of an electric field formed between the non-image portion of the electrostatic latent image formed on the image bearing member and the developer bearing member.

Abstract: The present invention relates to a developer remaining amount detecting apparatus in which a remaining amount of developer is detected on the basis of a developer using amount integrated by a developer using amount operating portion.

Abstract: A toner amount measuring apparatus includes an irradiating unit which divides a flux of laser beams emitted from a laser diode into two fluxes of laser beams by an obtuse-angled prism and makes the two light fluxes interfere with each other to form interference fringes on a photosensitive roll, and a photodetecting unit including an optical sensor for detecting reflection light obtained by reflecting the light constituting the interference fringes from the photosensitive roll.

Abstract: The present invention provides an image forming apparatus that has image forming device for forming a toner image, first detecting device for detecting the quantity of regularly reflected light from the toner image, and second detecting device for detecting the quantity of irregularly reflected light from the toner image.

Abstract: A method for detecting a toner concentration of a developer including toner particles provides that when developing a latent image having a predetermined area formed on a photoconductor using a developing member, a developing current flowing through the developing member is detected, and the toner concentration is calculated directly from the detected developing current and a toner developed area of the latent image.

Abstract: A method for detecting a toner concentration of a developer including toner particles provides that when developing a latent image having a predetermined area formed on a photoconductor using a developing member, a developing current flowing through the developing member is detected, and the toner concentration is calculated directly from the detected developing current and the predetermined toner developed area of the latent image obtained by counting toner dots in the predetermined area.

Abstract: A toner content control device for an electrophotographic apparatus of the type using a toner and carrier mixture. The control device determines an amount of toner replenishment on the basis of a difference between the toner content of the developer and a reference value, while correcting the reference value in accordance with the condition of a reference pattern formed on a photoconductive element. Although the control device includes a toner content sensor and a pattern density sensor, it omits conventional means for adjusting the toner content sensor. The control device is therefore capable of controlling image density stably with an inexpensive configuration.

Abstract: A method and apparatus in an electrostatographic reproduction machine having a plurality of development units for reliably producing high quality toner particle images under varying sustained area toner coverage conditions.

Abstract: A toner density a control device which has first toner density control device and a second toner density control device including a detecting member and, in case the density of the image detected by the detecting member changes by not less than a predetermined value with respect to a standard density, a ratio of the number of density controls by the second density control device with respect to the number of image formations changes.

Abstract: An image forming system adopting a dual-component inversion developing system for forming on an image carrier a toner patch image used for detecting an image concentration and controlling an image forming condition such as toner concentration based on the concentration of the toner patch image. The image forming system includes a charge unit for uniformly charging a surface of the image carrier, a developing magnet roll supplied with a developing bias, and a patch forming unit for selecting voltage application conditions to the charge unit and the developing magnet roll so as to reverse the bias potential relationship between the developing magnet roll and a charge potential of the image carrier and forming a first toner patch image at a contrast potential between the charge potential of the image carrier and the bias potential.

Abstract: A method and arrangement for adjusting density in electrophotographic printing are disclosed. A toner mark is printed at a predetermined location on each of sheets of a continuous stationery. A toner mark sensor is provided to detect density of the toner mark printed on each of the sheets. A controller performs density control based on a result from detecting density of toner mark printed on every other page of the sheets.

Abstract: An image forming apparatus in accordance with the invention includes a print engine with a photoreceptor, a laser exposure device for creating an image on the photoreceptor and one or more toning stations for toning the photoreceptor, after imaging. A system for enabling adjustment of the apparatus performance characteristics further includes a sensor for detecting characteristics of a toned image on the photoreceptor. A memory is provided for storing control parameters used to adjust operations of the printer; desired image characteristic parameters and previously measured image parameters. A processor is responsive to a performance assessment procedure for causing the print engine to create a toned test image on the photoreceptor. The processor then compares signals that are indicative of characteristic parameters of the toned test image with desired image characteristic parameters from the memory.

Abstract: An image forming apparatus that prepares a toner patch including a predetermined gradation area percentage on an image support to detect a developing concentration. An optical sensor detects reflected light from the background of the image support and reflected light from the toner patch prepared on the image support. The reflected light detected by the optical sensor is then controlled in response to the gradation area percentage of the prepared toner patch.

Abstract: A remaining amount of toner in an image forming apparatus is determined. The amount of toner remaining determines whether the image forming apparatus may be in a low toner state or a no toner state. An estimate of the amount of toner remaining is obtained by accurately estimating the amount of toner consumed. Latent patch images formed on a photoconductive member 1 by an exposure unit 3 are developed by developing device to obtain patch images. Densities of the patch images are measured by a patch sensor 22, and the contents of a weighting coefficient LUT 44 are changed. Meanwhile, the amount of toner developed, which corresponds to the changed weighting coefficient, is calculated by a development toner weight calculating unit 45 for each pixel on the basis of an exposure signal. This amount of toner developed is summed by a development toner weight summing unit 46. The amount of toner consumed is calculated as a function of the density measured by the patch sensor and the amount of toner developed.

Abstract: An electrostatographic recording apparatus and method includes a primary charger that establishes a uniform electrostatic charge on the image recording member in accordance with a first operating parameter. A recording device that imagewise modulates the charge on the image recording member to form electrostatic images in accordance with a second operating parameter and additionally forms a developable process control patch. A development station develops the electrostatic images and the control patch on the image recording member with toner in accordance with a third operating parameter. A transfer station transfers developed images from the image recording member. The transfer station includes a transfer member and power supply providing to the transfer member a transfer current used for transferring developed images. In one embodiment a sensor senses density of the developed control patch.

Abstract: An image forming apparatus, such as an electrophotographic copier, forms a test image on a photosensitive member, under constant image forming conditions, and the amount of toner adhering to the photosensitive member is detected. The detected amount of toner is converted into a developer toner concentration, based on a conversion standard. The toner concentration is used to control the operation of a toner replenishment device. The conversion standard is periodically corrected by forming a test image using a developer having a known toner concentration, detecting the amount of adhered toner, comparing the detected result to a standard value, and selecting one conversion standard table from among a number of different conversion tables.

Abstract: A method to provide a highly intelligent, automated diagnostic system that identifies the need to replace specific parts to minimize machine downtime rather than require extensive service troubleshooting. In particular, a systematic, logical test analysis scheme to assess machine operation from a simple sensor system and to be able to pinpoint parts and components needing replacement is provided by a series of first level of tests by the control to monitor components for receiving a first level of data and by a series of second level of tests by the control to monitor components for receiving a second level of data. Each of the first level tests and first level data is capable of identifying a first level of part failure independent of any other test. Each of the second level tests and second level data is a combination of first level tests and first level data or a combination of a first level test and first level data and a third level test and third level data.

Abstract: An unfixed toner image of a reference pattern is formed on a photosensitive member, the unfixed toner image is measured by a development density sensor 13, and the amount of toner to be supplied to a developing device 4 is controlled by a toner supply control unit 60 on the basis of a measurement output, thereby maintaining the image quality constant. If it is judged from a result of a detection of a state amount such as the temperature and the humidity by a state amount sensor 19 that there is a fear that the image quality exceeds an allowable range, a fixed image of a reference pattern is formed on a record medium such as a banner sheet, and the fixed image is measured by an optical sensor 10. Operation amounts such as the charge amount and the exposure value of an image output unit 100 are controlled by an image density control unit 20, thereby maintaining the image quality to be within the allowable range.

Abstract: Operation variables such as laser power, grid voltage, and developing bias are corrected by using image-density controlling rules so as to control the image density. Control of toner supply is also effected by using the image-density controlling rules. A solid density reference pattern corresponding to actual values of the operation variables is measured, and a rule which fits the solid density is used to correct the operation variables. A solid density to be obtained with standard values of the operation variables is calculated by using the composed rule. A standard solid density for a standard toner concentration or a standard toner charge amount is outputted, and is compared with the calculated solid density. The toner supply is controlled in such a manner that an error between the two solid densities becomes zero, to thereby ensure that the toner concentration in a developing device or the toner charge amount reaches a standard value.

Abstract: A method of development control by storing a reference tone reproduction curve and sensing a relatively small segment of an arbitrary image on an imaging surface. The relatively small segment of the arbitrary image on the imaging surface is then converted into suitable density values, such as background, solid area, and halftone and a control responds to the density values to adjust the machine operation for print quality correction.

Abstract: In a color image forming apparatus, plural different colored toner images are sequentially formed on an image forming body by repeating respective operations of plural chargers, plural imagewise exposure devices and plural developing devices so that a superimposed color image is formed on the image forming body. The color image forming apparatus further includes a detector provided inside and facing the image forming body, downstream of a developing device located in a most downstream position among the plural developing devices, for detecting the superimposed color image on the image forming body.

Abstract: An image forming apparatus includes a rotatable image bearing member for bearing a toner image and a toner image forming device for forming a toner image on said image bearing member. The toner image forming device is capable of forming a standard toner image and a plurality of reference toner images along a rotational direction of the image bearing member. The image forming apparatus also includes a density detecting device for detecting a density of the toner image on the image bearing member, a density control device for controlling the toner image forming device on the basis of an output of the detecting device from the standard toner image, a position detecting device for detecting a rotational angular position of the image bearing member, and a correcting device for correcting the density control device in accordance with an output of the density detecting device from the reference toner image, based on positional information of the position detecting device.

Abstract: The image forming apparatus is provided with a detecting means for detecting transfer efficiency when transferring a toner image from a photosensitive member to a transfer sheet, and a developing efficiency changing means for changing developing efficiency based on the transfer efficiency detected by the detecting means, and corrects the toner consumption predicted by the predicting means based on the transfer efficiency as detected by the detecting means, so as to determine the amount of toner to be replenished. When the developing efficiency is changed based on the transfer efficiency, toner consumption also changes, and does not match the predicted toner consumption. According to the present invention, toner concentration in a developer can be even more accurately controlled by correcting the predicted toner consumption by the change in transfer efficiency.

Abstract: An image forming apparatus forms a patch image on a recording medium, irradiates the patch image formed on the recording medium with light, and detects a quantity of light reflected by the patch image and outputs a first detection signal. The apparatus detects a quantity of light emitted by a light emission source and outputs a second detection signal, and amplifies the first detection signal in accordance with a first amplification gain and outputs a first amplified signal. The apparatus amplifies the second detection signal in accordance with a second amplification gain and outputs a second amplified signal, and controls image forming conditions based on the first amplified signal or the second amplified signal. An adjustment mode is executed prior to controlling the image forming conditions, and the first amplification gain is controlled when the patch image is formed with black toner, and the second amplification gain is controlled when the patch image is formed with color toner.

Abstract: In an electrostatographic process wherein images are formed on an electrostatic image supporting medium and developed by a development station having a developer formed of a mixture of toner and carrier particles, there is provided apparatus for controlling various processing control parameters in response to formation of a toned patch on the medium. The apparatus includes a first feedback controller that processes signals related to the parameter toning contrast in accordance with a closed loop control of this parameter. The first feedback controller serves as a toning contrast controller and outputs a first signal representing toner concentration set point in response to closed loop control of toning contrast. The apparatus also includes a second feedback controller means that is slaved to the first feedback controller and serves as a toner concentration (TC) controller.

Abstract: An hydraulic cylinder (100) driven by a reciprocating motive force operates in conjunction with two check valves (170) and (200) to pump liquid toner concentrate (150) around a loop from a reservoir bottle (180) and back into the bottle (180). A microprocessor circuit (230) analyzes commands and data bytes representative of the number and color of pixels transmitted from a computer (290) to an electrographic printer (280). When a predetermined pixel count has been reached, a microprocessor circuit (230), acting on positional information obtained from an optical sensor (240) and marks (250) and (260) on a wheel (160), causes a previously calculated volume of concentrate (150) to be added to a toner premix stream or reservoir in printer (280), thus replacing toner particles depleted from toner premix in the printer (280) during printing. The wheel (160) can run continuously to provide a stirring action for the concentrate (150).

Abstract: A device and method for detecting a toner image density accurately while using a characteristic curve found at the time of initialization. In the initialization, light of a first amount for low density is irradiated onto a photoreceptor from a density sensor, to acquire a first low-density light amount characteristic curve. In the characteristic curve, a toner image density corresponding to first density data is taken as a first reference density. A first amount of light for high density is then set to acquire a high-density light amount characteristic curve. In the characteristic curve, density data corresponding to the first reference density is taken as first correcting reference data. In density detection, a second amount of light for low density and a second amount of light for high density are found. A second low-density light amount characteristic curve corresponding to the second amount for low density is acquired.

Abstract: An image forming apparatus includes an image carrier on which a plurality of latent patch images are formed by exposure of different luminance, and the latent patch images are developed to form toner patch images. The apparatus further includes a gradation correction curve forming device in which a gradation correction curve is made from reflection density data of the patch toner image. The correction curve is formed, and gradation correction processing is conducted in accordance with the correction curve, so that an image forming process can be carried out. Further, when the correction curve cannot be obtained, at least one predetermined gradation curve stored in a memory in advance is selected as a substitution for the correction curve.