JP4725320B2 - Simulation apparatus and simulation method, image forming apparatus and image forming method, and computer program - Google Patents

Description

  The present invention relates to a simulation apparatus and simulation method, an image forming apparatus and an image forming method, and a computer program for analyzing the quality of an image formed by an electrophotographic process including processes such as toner development and toner image transfer. In particular, a simulation apparatus, a simulation method, an image forming apparatus, and an image that perform accurate image prediction by dividing the electrophotographic process into a plurality of subsystems, performing simulation calculation for each subsystem, and integrating the simulation results. The present invention relates to a forming method and a computer program.

  More specifically, the present invention performs simulation calculation by interpolating unknown coefficients included in a model expression expressing processing or phenomenon performed in each subsystem such as development and transfer based on input / output characteristics of the subsystem. The present invention relates to a simulation apparatus and a simulation method, an image forming apparatus and an image forming method, and a computer program, and in particular, eliminates an error factor when measuring the input / output characteristics of a subsystem and uses a more accurate model formula. The present invention relates to a simulation apparatus and a simulation method for performing simulation calculation, an image forming apparatus and an image forming method, and a computer program.

  2. Description of the Related Art Image forming apparatuses such as copying machines, facsimile machines, and printers using an electrophotographic process have features such as high speed and high image quality, and are widely used. In addition, due to the efficiency of office work and diversification of needs, there is still a high demand for improving the performance of electrophotographic process technology.

  In addition, along with the development of information technology, numerical analysis technology has been actively adopted in the design and development of electrophotographic processes. In other words, by performing a simulation calculation of the electrophotographic process, it is possible to predict the numerical reproduction of the electrophotographic image, that is, the output image without actually producing a prototype and performing an image formation experiment. In addition, the entire image forming apparatus can be evaluated, and image quality adjustment can be performed with high accuracy.

  The electrophotographic process includes a plurality of steps such as charging of an electrophotographic photosensitive member and exposure of a scanned original image, superposition of toner on an electrostatic latent image on the surface of the photosensitive member, development, transfer of toner to a transfer member, and fixing of transferred toner. Consists of. If the simulation of such a system is performed with a single simulator, the apparatus becomes huge and unrealistic. In view of this, for example, a method is considered in which simulations are modularized for each subsystem such as exposure / charging, development, transfer, and fixing, and simulation results from each simulation module are integrated.

  Processes or phenomena performed in each subsystem such as exposure, latent image, development, and transfer in the electrophotographic process are expressed by model equations. The model formula includes unknown coefficients, which can be interpolated or determined based on the input / output characteristics of the subsystem.

  For example, a method has been proposed in which input / output characteristics are experimentally measured for each subsystem such as exposure, latent image, development, transfer, etc., and fitted to a model equation (see, for example, Non-Patent Document 1). According to this simulation method, since a simple model formula can be used, there is an advantage that the calculation time is short.

The amount of toner developed into the electrostatic latent image on the photoreceptor in the development process is proportional to the developing portion electric field E. When considering a solid image (solid surface), the developing portion electric field E is proportional to the potential difference between the image portion latent image potential V _img and the developing bias potential V _bias on the photosensitive member. The developing toner amount DMA at this time is expressed by the following equation.

DMA = A1 (V _img −V _bias ) + A2

  In the above equation, the coefficients A1 and A2 are determined by the toner density, the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotational speed of the developing roller and the photosensitive member. These coefficients are obtained by performing experiments on the manufactured image forming apparatus (or experimental apparatus) while changing the respective conditions, and measuring the developing toner amount when the image portion latent image potential is changed. Can do. That is, the simulation calculation can be speeded up by simply expressing the model expression expressing the process by an expression interpolated with experimental data measured using a prototype or the like.

FIG. 11 shows an example of an experimental result in which the developing toner amount DMA with respect to the latent image potential is measured by changing the toner density _Tc of the developer to 6%, 8%, and 10%. As a method of measuring the amount of toner adhering to the photoreceptor, the toner is developed on an electrostatic latent image of a known area, the toner is adhered to an adhesive tape, and the amount of developed toner is measured from the difference in tape weight before and after the adhesion. The method of doing is mentioned. However, in this method, since charging and moisture absorption of the tape change with time, an error in measurement becomes large in an area where the amount of developing toner is small. In the experimental result shown in FIG. 11, the result according to the toner density _Tc is obtained in the region where the amount of the developing toner is large, but when the amount of the developing toner is small, the variation is large due to the influence of the measurement error. I understand.

  As described above, when the coefficients A1 and A2 on the process model equation are determined from the measured toner amount, the accuracy of the model equation is lowered due to the influence of such a measurement error. Particularly in a region where the amount of developing toner is small, the influence of measurement error is large, and the potential at which development is started varies greatly. When a tone reproduction simulation of a highlight portion (low density portion) of a halftone image important in color image formation is performed using such a model formula, there is a problem that a large difference from an actual process occurs.

  In the transfer process, a method of handling the scattering of the toner image as an image frequency transfer function is used. The image frequency transfer function MTF actually forms a development toner image and a transfer toner image of ladder images with different image frequencies, conducts experiments to measure the respective contrasts, and determines the contrast transfer amount for each image frequency from the contrast ratio. Then, it can be obtained by determining a point for each frequency by an interpolation method such as a spline.

  FIG. 12 shows an example of an experimental result in which a development toner image and a transfer toner image of ladder images having different image frequencies are formed, the contrast is measured, and the contrast transmission amount for each image frequency is obtained from the contrast ratio. . In this case, an error occurs in the contrast measurement due to the reverse polarity toner adhering between the ladders of the toner image of the ladder image developed on the photoconductor, so that the accuracy of the model formula is lowered. In particular, in a ladder image having a high image frequency, since the interval between ladders is narrow, the influence of such a measurement error becomes large. In the example shown in FIG. 12, the shape tends to vary with the high frequency component of the image frequency transfer function, and the contrast is not clear. When a simulation is performed using such a model formula, there is a problem in that the transfer state greatly differs from the actual process.

Bouyasu, Inoue, “Electrophotographic process simulation of digital copiers” (The Institute of Electrical Engineers of Japan, Institute of Static Equipment (VOL. SA-99 NO. 1-12, page 65-69, 1999)

  An object of the present invention is to provide an excellent simulation apparatus capable of dividing an electrophotographic process into a plurality of subsystems, performing simulation calculation for each subsystem, and performing accurate image prediction by integrating each simulation result, and A simulation method, an image forming apparatus, an image forming method, and a computer program are provided.

  A further object of the present invention is to perform more accurate simulation by interpolating unknown coefficients included in a model expression expressing processing or phenomenon performed in each subsystem such as development and transfer based on input / output characteristics of the subsystem. An object is to provide an excellent simulation apparatus and simulation method, an image forming apparatus and an image forming method, and a computer program capable of performing calculations.

  A further object of the present invention is to provide an excellent simulation apparatus and simulation method capable of performing a simulation calculation using a more accurate model expression by eliminating an error factor when measuring input / output characteristics of a subsystem. An image forming apparatus, an image forming method, and a computer program are provided.

  The present invention has been made in consideration of the above problems, and a first aspect thereof is a simulation apparatus for numerically analyzing a process including a plurality of subsystems realized by the behavior of a large number of particles. An input / output characteristic calculating means for calculating the input / output characteristics in the particle behavior analysis using the individual element method, and a model formula forming means for interpolating a coefficient in the model expression related to the subsystem based on the calculated input / output characteristics; A simulation apparatus comprising a numerical analysis means for numerically analyzing a phenomenon in a subsystem using a model formula.

  The present invention relates to a simulation apparatus that performs numerical analysis of a process including a plurality of subsystems including an electrophotographic process. Specifically, the electrophotographic process is divided into a plurality of subsystems, and simulation is performed for each subsystem. Calculation is performed, and the simulation results are integrated to perform final image prediction.

  Processes or phenomena performed in each subsystem such as exposure, latent image, development, and transfer are expressed by model equations. The model formula includes unknown coefficients, but these can be interpolated or determined based on the input / output characteristics of the subsystem, and a simple model formula can be used. There is.

  For example, there is a method of measuring input / output characteristics by experiment for each subsystem such as exposure, latent image, development, transfer, etc., and fitting it to a model formula. In this case, in addition to the need to manufacture a prototype, There is a problem that the accuracy of the model formula decreases due to the influence of measurement error of experimental data, and accurate simulation results cannot be obtained. For example, in the development process, when measuring the developing toner amount with respect to the latent image potential, the influence of the measurement error becomes large in a region where the developing toner amount is small, and when measuring the contrast transmission amount with respect to the image frequency, The influence of measurement error increases in the region.

  Therefore, in the simulation apparatus according to the present invention, the input / output characteristics of the subsystem are calculated using particle behavior analysis using the discrete element method, and unknown coefficients in the model formula are interpolated based on the calculation results. I made it.

  In such a case, an unknown coefficient can be fitted to the model formula without being affected by experimental errors or measurement errors. Further, since it is not necessary to manufacture a prototype for measuring the input / output characteristics of the subsystem, the development cost can be reduced and the development period can be shortened.

  The distinct element method is based on various forces acting on all particles (for example, acting force due to contact such as elastic force and viscous force, van der Worth force, mirror image force, external force such as liquid bridge force). This is already known as a particle behavior analysis method for calculating the behavior of each particle. Particle behavior analysis by the distinct element method has the merit that the behavior of powder consisting of countless particles can be evaluated in a more realistic manner, but the amount of calculation increases when the number of particles handled is enormous, There is a problem that it is difficult to calculate all particles in a realistic time. On the other hand, in the simulation apparatus according to the present invention, the particle behavior analysis by the individual element method is applied only when measuring the input / output characteristics of the subsystem, and after fitting the measurement result to the model formula, normal numerical values are used. Since the analysis is performed, an increase in calculation amount can be suppressed.

  For example, when the input / output characteristic calculation means changes the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotation speed of the developing roller and the photosensitive member using a development and transfer process analysis model based on the individual element method. The developed toner image on the surface of the photosensitive member is calculated, and the model formula forming unit uses the developed toner image calculated by the input / output characteristic calculating unit to develop the latent image potential of the photosensitive member. The numerical analysis means interpolates a model expression relating to the toner amount, and uses the model expression created by the model expression forming means to calculate the developing toner amount when the latent image potential of the photosensitive member is changed. it can.

  In such a case, the variation in the development start potential does not occur because the measurement error is not affected even in the region where the development toner amount is small. Therefore, there is no problem when the gradation reproduction simulation of the highlight portion (low density portion) of the halftone image, which is important in the formation of the color image, is performed.

  The input / output characteristic calculation means calculates a development toner image and a transfer toner image when the toner image formation conditions are changed using a development and transfer process analysis model by an individual element method, and the model formula formation means The contrast transfer amount and the image frequency transfer function for each image frequency are calculated from the development toner image and the transfer toner image calculated by the input / output characteristic calculation unit, and the numerical analysis unit is created by the model formula forming unit. The toner adhesion state on the transfer medium can be calculated using the obtained image frequency transfer function. That is, using a development and transfer process analysis model based on the individual element method, a toner image of a ladder image having a different image frequency is formed on a photoconductor, transferred onto a transfer medium, and a contrast between the developed toner image and the transferred toner image. And the contrast transfer amount for each image frequency is determined, and the image frequency transfer function can be calculated.

  In such a case, even in a region where the image frequency is high, it is not affected by the measurement error, so that there is no variation in shape in the high frequency component of the transfer function.

  According to a second aspect of the present invention, there is provided an image forming apparatus that corrects an image forming parameter by applying the simulation method according to the first aspect of the present invention. I / O characteristic calculation means that calculates by particle behavior analysis using the image, and image prediction means that fits the calculation results of the input / output characteristics to a model expression related to the subsystem and numerically analyzes the phenomenon in each subsystem to predict the image And an image forming parameter correcting means for correcting the image forming parameter in the electrophotographic process based on the result of the image prediction.

  In addition, fitting to the input / output characteristics model equations of each subsystem by particle behavior analysis based on the discrete element method, calculating image frequency transfer functions, and using these model equations and image frequency transfer functions, output images for input images May be predicted and presented to the user. Then, the image forming parameter may be changed based on an image quality setting change instruction input from the user who viewed the predicted image, and the output image may be predicted again based on the image forming parameter and presented to the user.

  According to a third aspect of the present invention, there is provided an image forming apparatus that performs failure analysis by applying the simulation method according to the first aspect of the present invention, and in each subsystem by particle behavior analysis based on the individual element method. An input / output characteristic calculation unit that calculates a model expression of the input / output characteristic and an image frequency transfer function, and an image prediction unit that predicts an output image with respect to the input image using the model expression and the image frequency transfer function. Failure analysis can be performed by comparing the formed images.

  In addition, the fourth aspect of the present invention is described in a computer-readable format so that a process for numerical analysis of a process composed of a plurality of subsystems realized by the behavior of a large number of particles is executed on a computer system. A computer program, based on the input / output characteristics calculation procedure for calculating the input / output characteristics in the subsystem by particle behavior analysis using an individual element method and the calculated input / output characteristics for the computer system. A computer program characterized by executing a model formula forming procedure for interpolating a model formula related to a subsystem and a numerical analysis procedure for numerically analyzing a phenomenon in the subsystem using the model formula.

  The fifth aspect of the present invention is an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing. A computer program written in a computer-readable format so as to execute processing for correcting image forming parameters when forming an image on a transfer medium on the computer system, By fitting the input / output characteristic calculation procedure for calculating the input / output characteristics in the subsystem by particle behavior analysis using the distinct element method and the input / output characteristics calculation results to the model formula for the subsystem, the phenomenon in each subsystem is Image prediction procedure for predicting images by numerical analysis, and images in the electrophotographic process based on the results of image prediction Is a computer program characterized by executing an image forming parameter correction procedure for correcting the formed parameter.

  The sixth aspect of the present invention is an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing. A computer program written in a computer-readable format so as to execute a process for performing failure analysis in an image forming apparatus for forming an image on a transfer medium on the computer system, the computer system Input / output characteristic calculation procedure for calculating input / output characteristic model expressions and image frequency transfer functions in each subsystem by particle behavior analysis based on the individual element method, and output images for input images using the model expressions and image frequency transfer functions An image prediction procedure for predicting the image, a predicted image in the image prediction procedure, and an input image on the image forming apparatus. By comparing the image formed on a computer program, characterized in that to execute the failure analysis procedure for failure analysis.

  The computer program according to each of the fourth to sixth aspects of the present invention defines a computer program described in a computer-readable format so as to realize predetermined processing on a computer system. In other words, by installing the computer program according to the fourth to sixth aspects of the present invention in the computer system, a cooperative action is exhibited on the computer system. The same effects as those of the simulation apparatus or the image forming apparatus according to the third aspect can be obtained.

  According to the present invention, an excellent simulation device capable of dividing an electrophotographic process into a plurality of subsystems, performing simulation calculation for each subsystem, and performing accurate image prediction by integrating each simulation result, and A simulation method, an image forming apparatus, an image forming method, and a computer program can be provided.

  Further, according to the present invention, an unknown coefficient included in a model expression expressing a process or phenomenon performed in each subsystem such as development and transfer is interpolated based on the input / output characteristics of the subsystem, and more accurate. An excellent simulation apparatus and simulation method, image forming apparatus and image forming method, and computer program capable of performing simulation calculation can be provided.

  In addition, according to the present invention, an excellent simulation apparatus and simulation method capable of performing simulation calculation using a more accurate model equation by eliminating an error factor when measuring the input / output characteristics of the subsystem. An image forming apparatus, an image forming method, and a computer program can be provided.

  The simulation apparatus according to the present invention calculates the input / output characteristics of each subsystem such as exposure, latent image, development, and transfer in an electrophotographic process using particle behavior analysis based on the individual element method, so that an experimental error and measurement can be performed. It is possible to fit to a model formula without being affected by errors. For example, when developing toner amount model type fitting in the developing process, variation in the development start potential occurs in a region where the amount of developing toner is small, and when fitting the image frequency transfer function in the transfer process, the transfer function high frequency However, according to the present invention, by calculating the input / output characteristics by particle behavior analysis based on the individual element method, the cause of these variations is eliminated, and the model formula is The accuracy of the simulation used can be increased.

  In addition, in the conventional method, since the input / output characteristics are measured on the prototype of each subsystem, the experiment cannot be performed before the actual device or the prototype of the developer. Since parameters necessary for particle behavior analysis such as physical property values can be set, input / output characteristics can be calculated even before trial production, and performance can be predicted by simulation calculation.

  For example, in the development process, when creating model equations for various conditions such as toner density and toner charge amount, the gap between the photosensitive member and the developing roller, and the rotation speed of the developing roller and the photosensitive member, the number of experiments in the conventional method is enormous. Therefore, a lot of experiment time and manpower are required, and an error occurs because the charged state of the developer varies with time and position. In contrast, according to the present invention, since the input / output characteristics can be calculated simply by changing the calculation conditions of the analysis model based on the individual element method, the charged state of the developer can be set to be constant. There is no occurrence.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  The present invention relates to a simulation apparatus that performs numerical analysis of an electrophotographic process including a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing. . First, the electrophotographic process will be described. FIG. 13 schematically shows a functional configuration of the electrophotographic process.

  In the charging unit, the surface of the photosensitive drum is charged to a uniform surface potential by a charger. Subsequently, the exposure means generates a light energy latent image corresponding to the image density by scanning the surface of the photoreceptor with a laser beam in accordance with image data obtained by scanning the document. An image drawn with light on the surface of the photoreceptor is converted into an image of charges by the photoconductivity of the photoreceptor, and an electrostatic latent image is formed.

  On the other hand, in the developing means, toner is supplied, mixed and stirred with the carrier, and both are electrostatically adsorbed by frictional charging while maintaining an appropriate toner concentration. The electrostatic latent image on the surface of the photosensitive member generates an electric field distribution in the development region, and the charged toner flies by an electrostatic force and is transferred onto the electrostatic latent image to generate a toner image.

  Thereafter, the transfer unit transfers the toner image onto the printing paper conveyed from the outside, and the fixing unit fixes the toner image on the printing paper by heating, melting, and pressing, and then the toner image is discharged out of the image forming apparatus. Make paper.

  Residual toner is removed from the surface of the photoreceptor after the transfer by a cleaning means. Although the residual potential remains on the photosensitive surface after cleaning, it is used for the next electrophotographic process after the initial potential is applied.

  FIG. 14 illustrates an apparatus configuration centering on the developing means.

  Around the photosensitive member 13, an intermediate transfer belt 14, a brush roller 34, a charging roller 36, and a developing unit are sequentially provided along the rotation direction b. The intermediate transfer belt 14, the brush roller 34, and the charging roller 36 are all in contact with the photosensitive surface of the photoreceptor 13. In addition, an LED array head 40 that performs line exposure on the photosensitive surface is disposed between the charging roller 36 and the developing unit.

  The developing unit includes a developing roller 38 disposed so as to face the photosensitive member 13, screw feeders 39 </ b> A and 39 </ b> B that are positioned below the developing roller 38 and supply a two-component developer to the developing roller 38, A developing roller 38 and a housing 37 for accommodating the screw feeders 39A and 39B are provided. The two-component developer contains toner and magnetic carrier particles as main components. An opening 37 </ b> A is provided in a portion of the housing 37 that faces the photoreceptor 13.

  The developing roller 38 is disposed so that a gap, that is, a developing gap is formed between the photosensitive roller 13 and the photosensitive surface. The developing roller 38 includes a cylindrical magnet roll 38B and a sleeve 38A that covers the magnet roll 38B. The magnet roll 38B has a cylindrical shape and is fixed to the image forming apparatus main body, and the sleeve 38A rotates around the axis of the magnet roll 38B in the counterclockwise direction on the paper surface in the same manner as the rotation direction b of the photoconductor 13. That is, it rotates in a direction facing the photoconductor 13 at a portion facing the photoconductor 13.

  The magnet roll 38B is a roller in which powder of a magnetic material such as ferrite or a rare earth magnet alloy is formed into a columnar shape or a cylindrical shape, and is magnetized so that the N pole and the S pole are arranged in a predetermined pattern. It is formed by sintering while. As the magnetized pattern, a portion facing the photosensitive member 13 is the developing pole S1, and a pick-off pole N1 is located next to the developing pole S1 along the rotation direction of the sleeve 38A, and a pickup pole N2 and a trimming pole are adjacent to the pick-up pole N1. Examples include a pattern in which magnetic poles are arranged in the order of S2 and the transport pole N3. The development pole S1 and the trimming pole S2 are all S poles, and the pickoff pole N1, the pickup pole N2, and the transport pole N3 are all N poles.

  A trimming blade 41 that aligns the height of the magnetic brush on the sleeve 38 </ b> A in cooperation with the trimming pole S <b> 2 extends toward the developing roller 38 at the opposing portion of the trimming pole S <b> 2. A negative developing bias voltage is applied to the developing roller 38.

  In the developing mode, the photosensitive member 13 rotates counterclockwise at a constant speed, so that the photosensitive surface is negatively charged by the charging roller 36. Next, the charged surface of the photosensitive surface is exposed by the LED array head 40, whereby the potential of the exposed portion of the charged surface is lowered to form an electrostatic latent image. In the developing unit, the developing roller 38 causes the toner charged to a negative voltage to be electrically attached to the electrostatic latent image formed on the photosensitive surface, that is, the potential lowering portion of the charging surface, similarly to the photosensitive member 13 and developed. As a result, a toner image is formed. The toner adhering to the photosensitive surface is electrically drawn toward the intermediate transfer belt 14 by the transfer roller 32 to which a positive transfer voltage having a polarity opposite to that of the toner is applied. As a result, the toner image on the photosensitive surface 13A is transferred from the photosensitive member 13 to the intermediate transfer belt.

  The toner is consumed each time the image is transferred, but new toner is supplied to the screw feeder 39B, mixed and stirred with the carrier, and electrostatically adsorbed by friction charging while maintaining an appropriate toner concentration (FIG. 15). checking).

  When the sleeve 38A rotates, the developer supplied into the housing 37 by the screw feeders 39A and 39B is adsorbed on the surface of the sleeve 38A by the pickup pole N2. Here, on the surface of the sleeve 38A, a magnetic field from the transport pole N3 toward the development pole S1, a magnetic field from the pick-off pole N1 toward the development pole S1, a magnetic field in the direction from the pickup pole N2 toward the trimming pole S2, and the transport pole N3. A magnetic field directed to the trimming pole S2 is formed, and the developer has a structure in which toner adheres to the surface of the magnetic carrier particles. Therefore, as shown in FIG. 16, the developer adsorbed on the surface of the sleeve 38A is arranged in the direction of the lines of magnetic force on the surface of the sleeve 38A, and rises to form a magnetic brush.

  As shown by the arrow in FIG. 16, the magnetic brush formed on the surface of the sleeve 38A in the vicinity of the pickup pole N2 is trimmed pole S2, transport pole N3, developing pole S1, and pick-off as the sleeve 38A rotates. It is conveyed from the right side to the left side of the page toward the pole N1. Then, the height of the magnetic brush is adjusted when passing through the trimming pole S2, and the toner on the magnetic brush is transferred to the photosensitive member 13 in the vicinity of the developing pole S1, so that the surface of the sleeve 38A is almost only a magnetic carrier. The magnetic brush remains. As the sleeve 38A rotates, the magnetic brush that has almost only the magnetic carrier drops off from the surface of the sleeve 38A at the pick-off pole N1 and returns to the inside of the housing 37.

  In the developing mode, the sleeve 38A rotates in this manner, so that fresh developer is always replenished at the pickup pole N2 and conveyed to the developing pole S1, and the toner is transferred to the photosensitive member 13 at the developing pole S1 to be photosensitive. The latent image on surface 13 is developed.

  Such an electrophotographic process is characterized by high speed and high image quality, but further performance improvement is required. Recently, numerical analysis technology has been actively adopted in the design and development of electrophotographic processes, and electrophotographic images can be predicted numerically without actually performing image formation experiments, and the entire process can be evaluated and adjusted. Is performed with higher accuracy. Also, if the entire electrophotographic process is simulated with a single system, the system becomes huge.For example, the simulation is modularized for each subsystem such as exposure / charging, development, transfer, fixing, etc. A method for integrating simulation results from a simulation module is considered.

  Processes or phenomena performed in each subsystem such as exposure, latent image, development, and transfer in the electrophotographic process are expressed by model equations. The model formula includes unknown coefficients, but these can be interpolated or determined based on the input / output characteristics of the subsystem, and a simple model formula can be used. There is.

  For example, there is a method of measuring input / output characteristics by experiment for each subsystem such as exposure, latent image, development, transfer, etc., and fitting it to a model formula. In this case, in addition to the need to manufacture a prototype, There is a problem that the accuracy of the model formula decreases due to the influence of measurement error of experimental data, and accurate simulation results cannot be obtained. For example, in the development process, when measuring the developing toner amount with respect to the latent image potential, the influence of the measurement error becomes large in a region where the developing toner amount is small, and when measuring the contrast transmission amount with respect to the image frequency, The influence of measurement error increases in the region.

  Therefore, in this embodiment, the input / output characteristics of the subsystem are calculated using particle behavior analysis using the individual element method, and unknown coefficients in the model formula are interpolated based on the calculation results. The distinct element method is based on various forces acting on all particles (for example, acting force due to contact such as elastic force and viscous force, van der Worth force, mirror image force, external force such as liquid bridge force). This is a particle behavior analysis method that calculates the behavior of each particle.

  This individual element method is applied to the carrier and toner particles during the development process, and the toner particles fly to the latent image on the photoconductor to form a toner image, and is applied to the toner particles during the transfer process. By analyzing the process of transferring the upper toner image onto the transfer medium, the electrophotographic process can be simulated with high accuracy by fitting unknown coefficients to the model formula without being affected by experimental or measurement errors. be able to. Further, since it is not necessary to manufacture a prototype for measuring the input / output characteristics of the subsystem, the development cost can be reduced and the development period can be shortened.

  FIG. 1 shows a functional configuration of a simulation apparatus that analyzes and calculates the behavior of toner particles in each subsystem of the electrophotographic process by an individual element method. The illustrated particle behavior analysis apparatus 100 includes a control unit 101, a data input unit 102, a model creation unit 103, a particle motion calculation unit 104, a data output unit 105, and a characteristic evaluation unit 106.

  The control unit 101 controls the entire processing in the particle behavior analysis apparatus 100.

  The data input unit 102 is a part that receives information necessary for the simulation calculation from another device or an input means (not shown) provided separately, and includes a particle property input unit 102A, a region data input unit 102B, The parameter input unit 102C is configured.

  In the particle characteristic input unit 102A, the physical characteristics (diameter, deposition density, etc.), mechanical characteristics (Young's modulus, Poisson's ratio, etc.), electromagnetic characteristics (dielectric constant, conductivity, charge amount, etc.) of the toner or carrier to be calculated are calculated. Etc. are entered.

  In the area data input unit 102B, the shape, physical characteristics, mechanical characteristics, electrical characteristics, and the like of the area in which the particle group moves are input.

  In the calculation parameter input unit 102C, in addition to the above, information related to the number of calculation steps, time increment, data output method, and the like necessary for executing the simulation calculation of particle motion is given.

  The model creation unit 103 is a part that generates numerical data for particle motion calculation, and includes a particle data generation unit 103A and a boundary data generation unit 103B. In these functional modules 103A and 103B, the characteristics of each boundary set for the particle or region to be analyzed are determined based on various information given by the data input unit 102.

  The particle motion calculation unit 104 uses the numerical data generated by the model creation unit 103 to perform an operation for obtaining the motion in the region for each particle to be analyzed based on the individual element method.

  In the individual element method, the behavior of the particle group is determined by solving the following equation of motion for each particle. Therefore, first, the external force f on the right side is evaluated. As the external force, mainly the contact force between particles, gravity, adhesion force, centrifugal force, air resistance force, and electromagnetic force are applied when an electromagnetic field is acting.

    mα = f (1)

  If the external force f is determined based on the contact force acting on the particles or the sum of the acting forces, the acceleration α of the particles can be obtained from the mass m given in advance. Then, for a given time increment, the velocity, displacement and coordinates of the particles are determined by numerically integrating the acceleration. By repeating such calculation for each particle to be analyzed for a predetermined number of calculation steps, the behavior of the particle group in the analysis region can be obtained.

  FIG. 2 shows a flowchart of the simulation calculation processing procedure based on the individual element method.

  First, initialization processing such as setting a default value for a predetermined variable is performed (step S1).

  Next, the contact determination between the particles is performed, and the contact force is calculated between the contacting particles (step S2).

  Next, the acting force acting on the particles is calculated (step S3). For example, in the simulation of the development process, electric field calculation is performed to obtain the Coulomb force acting on the toner as the analysis target particle. In addition, magnetic force, gravity and the like are calculated as other acting forces.

  Then, all the acting forces composed of the sum of the contact force and the acting force are calculated, and a motion equation for the particle is established to obtain acceleration, velocity, and displacement for the particle (step S4).

  The processes in steps S2 to S4 described above are repeated for each predetermined time step until the predetermined time to be analyzed is reached.

  In this way, by executing the analysis calculation for each particle sequentially, the particle behavior can be reproduced so as to be more faithful to reality.

  The data output unit 105 is a functional module that performs a process of transmitting the obtained particle behavior calculation result to another device as necessary. The particle coordinate / velocity output unit 105 </ b> A outputs the time change information of the coordinates and velocity of each particle. The boundary load output unit 105B outputs a load that acts on each boundary due to the contact of particles. The output destination device is, for example, a display that displays and outputs the particle behavior analysis result, a printer that prints out, or a database that stores data files of each calculation result.

  The characteristic evaluation unit 106 is a functional module that calculates various characteristics related to the performance as the image forming apparatus from the particle and boundary state obtained by calculation. As such characteristic calculation, for example, the density is obtained from the number of particles in a predetermined space, the average moving speed of the particles is obtained as an indicator of the flow state, or the number of toners and carriers is determined for each location. The mixing ratio is obtained.

  The particle behavior analysis apparatus 100 can be configured by a general computer system such as a personal computer, for example. Alternatively, a numerical computer can be configured by applying a grid computer or a parallel cluster PC in which a plurality of computer systems connected to a network operate cooperatively.

  The particle behavior analysis by the distinct element method has the merit that it is possible to evaluate the behavior of powder consisting of countless particles in a more realistic manner, but the calculation amount increases when the number of particles handled becomes enormous. There is a problem that it is difficult to calculate the particles in a realistic time. On the other hand, in this embodiment, particle behavior analysis by the individual element method is applied only when measuring the input / output characteristics of each subsystem, and normal numerical analysis is performed after fitting the measurement results to the model formula. Since this is performed, an increase in the amount of calculation can be suppressed.

  FIG. 3 schematically shows an analysis model of development and transfer processes by the individual element method. Using the analysis model shown in the figure, development is performed when the latent image potential of the photosensitive member is changed by changing the conditions such as the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotational speed of the developing roller and the photosensitive member. A simulation calculation for calculating the toner amount can be performed.

  In FIG. 4, using the development and analysis process analysis model based on the individual element method shown in FIG. 3, while changing the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotation speed of the developing roller and the photosensitive member, A processing procedure for performing a simulation calculation for calculating a developing toner amount when the latent image potential of the photosensitive member is changed is shown in the form of a flowchart.

  First, development conditions such as the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotation speed of the developing roller and the photosensitive member are set (step S11).

  Next, a solid image patch having a predetermined latent image potential is formed on the photoconductor (step S12).

  Next, the toner development process to the solid image patch is calculated by the particle behavior calculation based on the individual element method using the development process analysis model shown in FIG. 3 (step S13).

  Then, a developing toner amount DMA per unit area developed on the solid image patch on the photosensitive member is calculated from the calculation result of the toner developing process (step S14).

  The developing toner amount calculation process as described above is repeatedly executed while changing the latent image potential (Step S16) until the processing is completed for all sample points in the desired latent image potential range (No in Step S15). .

FIG. 5 shows the result of calculating the developing toner amount when the latent image potential of the photosensitive member is changed according to the processing procedure shown in FIG. 4 while changing the toner density _Tc as a condition. When simulation calculation is performed on the input / output characteristics of the development and transfer processes using the measurement results from experiments on the prototype, measurement errors are greatly affected in areas where the amount of developed toner is small, and the potential at which development starts begins to vary greatly. Therefore (see FIG. 11), it becomes a problem when the gradation reproduction simulation of the highlight portion (low density portion) of the halftone image, which is important in the formation of the color image, is performed. On the other hand, in this embodiment, as can be seen from FIG. 5, since the measurement error is not affected even in a region where the amount of the developing toner is small, the development start potential does not vary.

  Further, in FIG. 6, a toner image of a ladder image having a different image frequency is formed on a photosensitive member using a development and analysis process analysis model based on the individual element method shown in FIG. 3, and transferred onto a transfer medium. Then, a processing procedure for performing a simulation calculation for calculating the contrast of the developed toner image and the transferred toner image and obtaining the contrast transmission amount for each image frequency is shown in the form of a flowchart.

  First, development conditions such as the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotation speed of the developing roller and the photosensitive member are set (step S21).

  Next, a ladder image patch having a predetermined image frequency is formed on the photosensitive member at a predetermined latent image potential (step S22).

  Next, the toner development process to the ladder image patch on the photoconductor is calculated by the particle behavior analysis based on the individual element method, using the development process analysis model shown in FIG. 3 (step S23).

Next, the toner image profile of the ladder image patch developed on the photosensitive member is calculated from the result of the development process calculation, and the contrast C _deve is obtained from the maximum value P _max and the minimum value P _{min of the} profile by the following equation (step) S24).

C _deve = (P _max -P _min ) / (P _max + P _min )

  Next, by the particle behavior analysis based on the individual element method, the transfer process of the ladder image patch / toner image formed on the photoconductor to the transfer medium is calculated using the transfer process analysis model shown in FIG. S25).

Next, the toner image profile of the ladder image patch transferred to the transfer medium is calculated from the transfer process calculation result, and the contrast C _trans is obtained from the maximum value P _max and the minimum value P _{min of the} profile by the following equation (step S26). ).

C _trans = (P _max −P _min ) / (P _max + P _min )

Then, from the ratio of the contrast C _trans calculated in contrast C _deve the transcription process calculated in developing process, obtains the contrast transfer amount C _T (step S27).

The process of calculating the contrast transfer amount C _T as described above, until completed for all the sample points in the range of a desired image frequency (No in step S28), while changing the image frequency (step S29), and repeatedly executes .

  FIG. 7 shows the result of calculating the contrast transmission amount for each image frequency in accordance with the processing procedure shown in FIG. When the input and output characteristics of the development and transfer processes are simulated using the results of experiments on prototypes, errors in contrast measurement occur due to the reverse polarity toner, especially in the high-frequency region where the interval between ladder images is narrow. Therefore, there is a problem that the shape varies (see FIG. 12). On the other hand, in this embodiment, as can be seen from FIG. 7, since the measurement error is not affected even in a region where the image frequency is high, there is no variation in the shape of the high-frequency component of the transfer function.

  Further, an application example in which image prediction is performed and image forming parameters are corrected by applying the electrophotographic process simulation method according to the present embodiment to an image forming apparatus is also conceivable. In other words, the input / output characteristics of the subsystem are calculated by particle behavior analysis using the distinct element method, and the calculation results of the input / output characteristics are fitted to the model formula for the subsystem, and the phenomena in each subsystem are numerically analyzed. Image prediction. Then, the image forming parameters in the electrophotographic process are corrected based on the result of image prediction, and a higher quality image is formed on the transfer medium.

  For example, fitting to the input / output characteristics model formula of each subsystem by particle behavior analysis based on the individual element method, calculating the image frequency transfer function, and using these model formula and image frequency transfer function, output density and gradation The image forming parameters used when the image forming apparatus outputs an image can be corrected by predicting the sex variation.

  FIG. 8 shows a processing procedure of the image forming apparatus in this case in the form of a flowchart.

  First, the current state of the image forming apparatus such as the cumulative number of prints, temperature, and humidity is detected (step S31).

  Next, with respect to each state of the image forming apparatus, using a development model based on the individual element method, a reference pattern image for density / gradation property detection is calculated from the image formation state calculated in advance and the development toner amount characteristic with respect to the latent image potential. The developing toner amount is calculated (step S32). Further, when the developing toner amount with respect to the latent image potential is not calculated for the current value of each state, the calculation is performed by interpolation or extrapolation from two calculation results close to the current value calculated in advance.

  Next, based on the calculated development toner amount of the input image and contrast transfer characteristics calculated in advance using a transfer model based on the individual element method for each state, a reference pattern for density / gradation detection formed on the photoconductor The transfer state of the image onto the transfer medium is calculated (step S33). Here, when the contrast transmission amount is not calculated for the current value of each state, it is calculated by interpolation or extrapolation from two calculation results close to the current value calculated in advance.

  Next, output density and gradation are calculated from the calculated density / gradation property detection reference pattern image after transfer, and set as an output predicted value (step S34).

  Then, the predicted output value is compared with the target value of the output density and gradation, and the correction amount of the image forming parameters such as the charging potential, the exposure light amount, and the toner replenishment amount is determined so as to approach the target value (step S35).

  In addition, fitting to the input / output characteristics model equations of each subsystem by particle behavior analysis based on the discrete element method, calculating image frequency transfer functions, and using these model equations and image frequency transfer functions, output images for input images May be predicted and presented to the user. Then, the image formation parameter is changed based on the change instruction of the image quality setting input from the user who viewed the predicted image, and the output image is predicted again based on the image formation parameter and presented to the user.

  FIG. 9 shows a processing procedure of the image forming apparatus in this case in the form of a flowchart.

  First, the current state of the image forming apparatus such as the cumulative number of prints, temperature, and humidity is detected (step S41).

  Next, for each state, the development toner amount for the input image is calculated from the development toner amount characteristic with respect to the latent image potential calculated in advance using a development model based on the individual element method (step S42). Here, when the developing toner amount with respect to the latent image potential is not calculated with respect to the current value in each state, it is calculated by interpolation or extrapolation from two calculation results close to the current value calculated in advance.

  Next, the transfer state of the input image formed on the photosensitive member to the transfer medium is calculated from the calculated development toner amount of the input image and the contrast transfer characteristic calculated in advance using a transfer model based on the individual element method for each state. Is calculated (step S43). Here, when the contrast transmission amount is not calculated for the current value of each state, it is calculated by interpolation or extrapolation from two calculation results close to the current value calculated in advance.

  Next, the calculated state of the input image after transfer is displayed and output as an output image prediction result on a monitor / display connected to the image forming apparatus (step S44).

  Then, the user can refer to the output image prediction result and instruct to change image quality settings such as image sharpness and color balance (step 45).

  Here, when an instruction to change the image setting is given (Yes in step S46), image processing corresponding to the image quality setting set for the input image is performed (step S47).

  In addition, the electrophotographic process simulation method according to the present embodiment is applied to an image forming apparatus to perform image prediction, and the failure analysis of the apparatus is performed by comparing the predicted image with an actually formed image. Examples are also possible.

  FIG. 10 shows a processing procedure of the image forming apparatus in this case in the form of a flowchart.

  When a failure occurs such as an image defect occurring in the image forming process (step S51), first, the user inputs a classification closest to the failure content to the image forming apparatus (step S52).

  Next, a failure detection image capable of detecting the failure content selected by the user is output from the image forming apparatus (step S53). The failure detection image referred to here is, for example, a superimposed image of predetermined density patches of each color of YMC with respect to the failure content that the color reproduction of the image is abnormal.

  Next, the image formation parameter related to the failure content input by the user is set to the failure state, and the failure detection image is determined based on the development toner amount characteristic with respect to the latent image potential calculated in advance using the development model based on the individual element method. The developing toner amount is calculated (step S54).

  Next, image formation parameters related to the failure content input by the user are set to failure state, and the failure detection formed on the photoconductor is detected from contrast transfer characteristics calculated in advance using a transfer model based on the individual element method. The transfer state of the image onto the transfer medium is calculated (step S55).

  Next, the calculated state after transfer of the failure detection image is output as a failure cause estimation result on a display device provided in the image forming apparatus (step S56).

  Next, the user compares the failure detection image with the failure cause prediction result to determine whether or not the failure is caused (step S57).

  If the user determines that the cause is not a failure (No in step S58), the image formation parameter value or parameter type related to the failure content is changed (step S59), and the process returns to step S54 to return to the failure. Repeat the cause estimation.

  If the user determines that the cause of the failure is present (Yes in step S58), if the image forming apparatus can repair the cause of the failure, a repair process is performed. If repair by an engineer or the like is required, a method for dealing with the cause of failure is displayed on the display device (step S60).

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiment without departing from the gist of the present invention.

  In the present specification, the embodiment applied to the electrophotographic process has been mainly described, but the gist of the present invention is not limited to this. The present invention can be similarly applied to other systems that numerically analyze a process including a plurality of subsystems realized by the behavior of a large number of particles.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims should be taken into consideration.

FIG. 1 is a diagram showing a functional configuration of a simulation apparatus that analyzes and calculates the behavior of toner particles in each subsystem of the electrophotographic process by an individual element method. FIG. 2 is a flowchart showing a processing procedure of simulation calculation based on the individual element method. FIG. 3 is a diagram schematically showing an analysis model of development and transfer processes by the individual element method. FIG. 4 shows the development and analysis process analysis model based on the individual element method shown in FIG. 3, while changing the toner charge amount, the gap between the photosensitive member and the developing roller, and the rotational speed of the developing roller and the photosensitive member. 7 is a flowchart showing a processing procedure for performing a simulation calculation for calculating a developing toner amount when a latent image potential of a body is changed. FIG. 5 is a diagram showing the result of calculating the developing toner amount when the latent image potential of the photosensitive member is changed according to the processing procedure shown in FIG. 4 while changing the toner density as a condition. FIG. 6 shows a development and analysis process analysis model based on the individual element method shown in FIG. 3. A toner image of a ladder image having a different image frequency is formed on a photoconductor, transferred onto a transfer medium, and developed. 6 is a flowchart showing a processing procedure for calculating a contrast of a toner image and a transfer toner image and performing a simulation calculation for obtaining a contrast transmission amount for each image frequency. FIG. 7 is a diagram showing the result of calculating the contrast transmission amount for each image frequency in accordance with the processing procedure shown in FIG. FIG. 8 shows fitting of the input / output characteristics of each subsystem to model equations by particle behavior analysis based on the individual element method, calculating image frequency transfer functions, and using these model equations and image frequency transfer functions, 10 is a flowchart illustrating a processing procedure for correcting an image forming parameter used when an image forming apparatus outputs an image by predicting a gradation variation. FIG. 9 shows fitting of the input / output characteristics of each subsystem to model equations by particle behavior analysis based on the individual element method, calculating image frequency transfer functions, and using these model equations and image frequency transfer functions, It is the flowchart which showed the process sequence which estimates and shows an output image to a user. FIG. 10 is a flowchart showing a processing procedure of the image forming apparatus for performing image prediction and performing failure analysis by comparing the predicted image with an actually formed image. FIG. 11 is a diagram illustrating an example of an experimental result in which the developing toner amount DMA with respect to the latent image potential is measured by changing the toner density _Tc of the developer to 6%, 8%, and 10%. FIG. 12 is a diagram illustrating an example of an experimental result of forming a development toner image and a transfer toner image of ladder images having different image frequencies, measuring the contrast, and obtaining the contrast transmission amount for each image frequency from the contrast ratio. is there. FIG. 13 is a diagram schematically showing a functional configuration of the electrophotographic process. FIG. 14 is a diagram showing an apparatus configuration example around the developing means. FIG. 15 is a diagram illustrating a state in which the toner and the carrier are transported while being mixed and stirred in the screw feeder B. FIG. 16 is a diagram showing a state in which the magnetic brush is formed on the surface of the sleeve 38 </ b> A in the direction of the magnetic field lines, and rising.

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 ... Photoconductor 14 ... Intermediate transfer belt 32 ... Transfer roller 34 ... Brush roller 36 ... Charging roller 37 ... Housing 38 ... Developing roller 39 ... Screw feeder 40 ... LED array head 41 ... Trimming blade 100 ... Particle behavior analysis apparatus 101 ... Control unit 102 ... Data input unit 103 ... Model creation unit 104 ... Particle motion calculation unit 105 ... Data output unit 106 ... Characteristic evaluation unit

Claims (13)

A simulation device for numerically analyzing a process composed of a plurality of subsystems realized by the behavior of a large number of particles,
Input / output characteristic calculation means for calculating input / output characteristics in the subsystem by particle behavior analysis using the individual element method;
A model formula forming means for interpolating a model formula related to the subsystem based on the calculated input / output characteristics;
Numerical analysis means for numerically analyzing phenomena in subsystems using model formulas;
A simulation apparatus comprising: An integrated evaluation means for evaluating the performance of the entire process by integrating numerical analysis results for each subsystem is further provided.
The simulation apparatus according to claim 1. 2. A numerical analysis of an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing. 1. The simulation apparatus according to 1. Image forming apparatus for forming an image on a transfer medium by an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing Because
Input / output characteristic calculation means for calculating input / output characteristics in the subsystem by particle behavior analysis using the individual element method;
Image prediction means for fitting the calculation result of the input / output characteristics to a model expression related to the subsystem, numerically analyzing the phenomenon in each subsystem, and predicting the image,
Image formation parameter correction means for correcting image formation parameters in the electrophotographic process based on the result of image prediction;
An image forming apparatus comprising: Image forming apparatus for forming an image on a transfer medium by an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing Because
Input / output characteristic calculation means for calculating a model expression and an image frequency transfer function of input / output characteristics in each subsystem by particle behavior analysis based on the individual element method;
Image prediction means for predicting an output image for an input image using the model formula and an image frequency transfer function;
Image forming means for forming an output image with respect to an input image by an electrophotographic process;
A failure analysis means for performing failure analysis by comparing a predicted image by the image prediction means and an image actually formed by the image forming means;
An image forming apparatus comprising: A simulation method for numerical analysis of a process consisting of a plurality of subsystems realized by the behavior of a large number of particles,
Input / output characteristic calculation step for calculating input / output characteristics in the subsystem by particle behavior analysis using the individual element method,
A model formula forming step of interpolating a model formula related to the subsystem based on the calculated input / output characteristics;
A numerical analysis step for numerically analyzing phenomena in the subsystem using a model formula;
A simulation method characterized by comprising: The system further includes an integrated evaluation step for integrating the numerical analysis results for each subsystem to evaluate the performance of the entire process.
The simulation method according to claim 6. Numerical analysis of an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing.
The simulation method according to claim 6. Image forming method for forming an image on a transfer medium by an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing Because
Input / output characteristic calculation step for calculating input / output characteristics in the subsystem by particle behavior analysis using the individual element method,
An image prediction step for fitting the calculation result of the input / output characteristics to a model expression related to the subsystem, and numerically analyzing the phenomenon in each subsystem to predict an image,
An image formation parameter correction step for correcting the image formation parameter in the electrophotographic process based on the result of image prediction;
An image forming method comprising: Image forming method for forming an image on a transfer medium by an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing Because
An input / output characteristic calculation step for calculating an input / output characteristic model formula and an image frequency transfer function in each subsystem by particle behavior analysis based on the individual element method;
An image prediction step for predicting an output image for an input image using the model formula and an image frequency transfer function;
An image forming step of forming an output image with respect to the input image by an electrophotographic process;
A failure analysis step for performing failure analysis by comparing a predicted image in the image prediction step and an image actually formed in the image formation step;
An image forming method comprising: A computer program written in a computer-readable format so that a process for numerical analysis of a process composed of a plurality of subsystems realized by the behavior of a large number of particles is executed on a computer, the computer comprising:
Input / output characteristic calculation means for calculating input / output characteristics in the subsystem by particle behavior analysis using the individual element method,
Model formula forming means for interpolating a model formula related to the subsystem based on the calculated input / output characteristics,
Numerical analysis means for numerically analyzing phenomena in subsystems using model formulas,
Computer program to function as An image when an image is formed on a transfer medium by an electrophotographic process including a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing. A computer program written in a computer-readable format to execute a process for correcting a forming parameter on a computer, the computer comprising:
Input / output characteristic calculation means for calculating input / output characteristics in the subsystem by particle behavior analysis using the individual element method,
Image prediction means for fitting the calculation result of the input / output characteristics to a model formula for the subsystem and numerically analyzing the phenomenon in each subsystem to predict the image,
Image formation parameter correction means for correcting image formation parameters in the electrophotographic process based on the result of image prediction;
Computer program to function as Image forming apparatus for forming an image on a transfer medium by an electrophotographic process comprising a plurality of subsystems including exposure to a photoreceptor, formation of an electrostatic latent image, development of a toner image, transfer of a toner image to a medium, and fixing A computer program described in a computer-readable format so as to execute a process for performing failure analysis in the computer, the computer comprising:
Input / output characteristic calculating means for calculating the input / output characteristic model formula and image frequency transfer function in each subsystem by particle behavior analysis based on the individual element method,
Image predicting means for predicting an output image for an input image using the model formula and an image frequency transfer function;
Image forming means for forming an output image with respect to an input image by an electrophotographic process;
A failure analysis unit that performs failure analysis by comparing a predicted image by the image prediction unit with an image actually formed by the image forming unit;
Computer program to function as

Images