JP2006267973A - Image forming apparatus and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the image forming by obtaining the powder density and fluidity of a toner highly precisely without increasing measuring instruments, etc. <P>SOLUTION: A simulation calculation part 200 simulates the movement of toner particles and calculates their powder density and fluidity. The data of the powder density and the data of the fluidity calculated by the simulation calculation part 200 are supplied to a sensitivity correction quantity determination part 20 and a consumption correction quantity determination part 21. The sensitivity correction quantity determination part 20 generates data of sensitivity correction quantity for correcting the sensitivity of a toner concentration sensor 13b from the data of the powder density and fluidity. The data of sensitivity correction quantity is supplied to a correction input terminal of the toner concentration sensor 13b and corrects the sensitivity of the toner concentration sensor 13b. The consumption correction quantity determination part 21 corrects the consumption toner quantity from the powder density and fluidity. A remaining quantity detection part 22 calculates the accumulated consumption quantity from the correction quantity of the consumption toner quantity, and obtains the remaining quantity of the toner. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming technique using a toner or a developer, and in particular, can reliably cope with fluctuations in bulk density and fluidity of the toner or developer at a low cost.

  In an image forming apparatus using toner or developer, there are known problems that the toner replenishment amount changes and the toner density sensor sensitivity changes depending on the density and fluidity of the toner and developer. Therefore, since it is difficult to directly measure the density and fluidity of toner and developer, it is necessary to measure the density and fluidity of the developer according to various substitute characteristics, and to directly measure the density and fluidity of the developer. The means of measurement has been reported. Hereinafter, the toner or developer may be simply referred to as toner.

  For example, Patent Document 1 proposes to control the toner replenishment amount under the fluidity condition obtained at the time of toner production. Patent Document 2 proposes measuring the bulk density with a magnetic sensor. Japanese Patent Application Laid-Open No. H10-260260 proposes to detect the bulk based on the humidity and the remaining amount of toner and to control toner supply. Japanese Patent Application Laid-Open No. H10-260260 proposes to provide toner replenishment control by providing means for measuring fluidity (switch based on the weight of staying toner). Patent Document 5 proposes to measure toner fluidity with a piezoelectric vibrator. Patent Document 6 proposes to measure toner fluidity with a thickness shear vibrator that emits a transverse wave ultrasonic wave. Japanese Patent Application Laid-Open No. H10-228561 proposes to control the toner supply by calculating the fluidity from the accumulated toner supply time and the remaining amount.

But both
(1) Low accuracy due to prediction from substitute characteristics such as environment, toner remaining amount, developer retention state, etc.
(2) Special measuring equipment is required, and there are problems in size and cost.
(3) The information at the time of manufacturing the toner developer cannot cope with the change over time due to the use conditions of the image forming apparatus.
There are issues such as.

Up to now, the density and fluidity of the toner that changes over time due to various external factors such as the usage environment, the usage image density, the number of sheets used, and the relationship with the container in which the toner and developer are placed have high accuracy. There is no method for measurement, and as a result, there has been no method for accurately correcting toner replenishment and toner density sensor errors due to changes in toner density and fluidity.
JP 2001-201929 A JP 2003-162140 A Japanese Patent Laid-Open No. 04-170563 JP 06-059571 A Japanese Patent Laid-Open No. 06-167437 Japanese Patent Laid-Open No. 06-167886 JP 10-077866 A

  The present invention has been made in consideration of the above circumstances, and provides a technique for accurately correcting toner replenishment and toner density sensor errors due to changes in toner density and fluidity without using a special measuring device. The purpose is to do.

  According to the configuration example of the present invention, in order to achieve the above-described object, conventionally, predictive control is performed with substitute characteristics by accurately calculating the physical characteristics of toner particles over time by particle motion simulation. Further, correction accuracy such as magnetic toner density sensor correction, toner replenishment amount correction, or toner remaining amount prediction correction based on the bulk density and fluidity of toner can be improved. Further, since no measuring device for measuring the bulk density and fluidity of toner is required, there are no problems in size and cost.

  In a configuration example in which the present invention is applied to a two-component development type image forming apparatus of a type in which a magnetic toner density sensor is provided in a developing machine, environmental information input (environment sensor output, development) is performed using a particle motion simulation execution unit. The bulk density and fluidity of the developer are calculated according to the machine driving time, the image image density, etc., and at least one of the following processes is performed based on the calculated bulk density and fluidity.

(1) Correct the sensitivity of the toner density sensor. (2) Correct the toner supply amount by toner supply control according to the output of the toner density sensor.
(3) Create a toner band for forced toner consumption.
(4) Forcible toner supply.

  Further, in a configuration example in which the present invention is applied to an image forming apparatus of a two-component development type in which the toner replenishment amount is controlled based on the image density or the toner consumption amount predicted from the image data of the printed document, Calculate the bulk density and fluidity of the developer according to the environmental information input (environmental sensor output, developer drive time, image image density, etc.) using the motion simulation execution unit, and based on the calculated bulk density and fluidity Then, at least one of the following processes is performed.

(1) Correct the toner supply amount by the toner supply control means (2) Create a toner band for forced toner consumption (3) Perform forced toner supply

  The outline of particle motion simulation is as follows.

[Input information]
(1) Particle characteristics such as toner, developer particle system, shape, density, charge, Young's modulus, Poisson's ratio, friction coefficient, etc. (2) Area characteristics such as Young's modulus, Poisson's ratio, friction coefficient of developing machines, etc. (3) Environmental information such as temperature / humidity, time, image density information of image, etc.

[Output information]
(1) Time variation of particle position, that is, the number of particles in a predetermined region at a certain time.
From this, the bulk density of the particles can be determined.
(2) Average velocity of particles From this, the fluidity of the particles can be determined.

  Further, the present invention will be described.

  According to the present invention, in order to achieve the above-mentioned object, the image forming apparatus: a calculation means for performing a simulation of the temporal change and average speed of the particle position for the toner particles based on the particle characteristics, the area characteristics, and the environmental information. A bulk density calculating means for calculating the bulk density from the time change of the particle position obtained from the simulation by the calculating means; and the fluidity of the developing particles from the average speed obtained from the simulation by the calculating means. Fluidity calculating means for calculating; and control system correcting means for correcting the control system for image formation based on the calculated bulk density and the fluidity are provided.

  In this configuration, it is possible to accurately control the image formation by accurately grasping the bulk density and fluidity of the toner. In addition, since there is no need for a measuring device for measuring the bulk density and fluidity of the toner, there are no problems with size and cost.

  In this configuration, the image formation control system corrected by the control system correction unit includes, for example, a magnetic toner density sensor disposed in the developing unit. In this case, the control system correction unit includes the toner density sensor. Correct the sensitivity of the sensor.

  The replenishment amount control itself of the toner replenishing means may be corrected without correcting the sensitivity of the toner density sensor or in combination with the correction of the toner density sensor.

  Further, for example, in the case of including a replenishing unit that replenishes toner based on the toner density estimated from the image density or the image data of the printed document, the control system correcting unit corrects the replenishment amount control of the replenishing unit. May be.

  Further, remaining amount estimating means for estimating the remaining amount of developing particles may be further provided, and the control system correcting means may correct the estimated value of the remaining amount estimating means.

  The particle characteristics include, for example, toner particle system, shape, density, charge, Young's modulus, Poisson's ratio, and friction coefficient.

  The region characteristics include, for example, Young's modulus, Poisson's ratio, and friction coefficient of each member of the developing machine.

  The environmental information includes, for example, temperature change information of the particle characteristics based on temperature and humidity, time, and image density information of the image.

  The present invention can be realized not only as an apparatus or a system but also as a method. Of course, a part of the invention can be configured as software. Of course, software products used for causing a computer to execute such software are also included in the technical scope of the present invention.

  These and other aspects of the invention are set forth in the appended claims and will be described in detail below with reference to examples.

  According to the present invention, it is possible to accurately control the image formation by accurately grasping the bulk density and fluidity of the toner. In addition, since there is no need for a measuring device for measuring the bulk density and fluidity of the toner, there are no problems with size and cost.

  Examples of the present invention will be described below.

  FIG. 1 shows an embodiment in which the present invention is applied to an image forming apparatus having a toner density sensor. In this example, only one image forming portion is shown, but a plurality of image forming portions may be provided in accordance with the color image. Further, in the figure, the portion related to the present invention is mainly shown, and the fixing unit or the like is not shown, but it is needless to say that it can be provided as appropriate.

  In FIG. 1, an image forming apparatus 100 includes a photoconductor 10, a charging unit 11, an exposure unit 12, a developing unit 13, a transfer unit 14, a cleaning unit 15, a paper transport mechanism 16, and the like. The photoconductor 10, the charging unit 11, the exposure unit 12, the developing unit 13, the transfer unit 14, the cleaning unit 15, and the paper transport mechanism 16 are ordinary electrophotographic systems. The photosensitive member 10, the charging roll of the charging unit 11, the developing roll of the developing unit 13, and the transfer roll of the transfer unit 14 are rotated as indicated by arrows. As is well known, the surface of the photoreceptor 10 is charged to a predetermined potential using the charging unit 11, the surface of the photoreceptor 10 is exposed by the exposure unit 12 to form a latent image, and the toner image is developed in the developing unit 13. In the transfer unit 14, the toner image is transferred to a recording medium (not shown). The recording medium carrying the toner image is fixed by a fixing unit (not shown).

  The developing unit 13 has, for example, a magnetic toner density sensor 13b at the bottom position. The toner concentration sensor 13b detects the toner concentration based on the change in magnetic permeability in the measurement atmosphere, that is, the amount of magnetic carrier. The detection signal of the toner density sensor 13b is supplied to the toner replenishment amount control unit 13c. The toner replenishment amount control unit 13c controls the toner replenishment unit 13a so that the toner concentration becomes a predetermined target value by adjusting the operation amount.

  In this embodiment, the simulation calculation unit 200 simulates the movement of toner particles and calculates the bulk density and fluidity. This will be described in detail later. Bulk density data and fluidity data calculated by the simulation calculation unit 200 are supplied to the sensitivity correction amount determination unit 20 and the consumption correction amount determination unit 21. The sensitivity correction amount determination unit 20 generates sensitivity correction amount data for correcting the sensitivity of the toner density sensor 13b based on the bulk density and fluidity data. The sensitivity correction amount data is supplied to the correction input terminal of the toner density sensor 13b to correct the sensitivity of the toner density sensor 13b. For example, the bias level of the amplifier circuit of the toner density sensor 13b is changed. The consumption correction amount determination unit 21 corrects the consumed toner amount based on the bulk density and the fluidity, and the remaining amount detection unit 22 calculates the cumulative consumption amount based on the correction amount of the consumed toner amount and calculates the toner. Find the remaining amount.

  In this embodiment, the toner supply amount can be controlled with high accuracy by correcting the sensitivity of the toner concentration sensor 13b based on the bulk density data and the fluidity data obtained by the simulation calculation unit 200. Further, as indicated by a broken line in the figure, the toner replenishment control itself of the toner replenishment amount control unit 13c may be corrected based on the bulk density data and the fluidity data. Further, when creating a toner band for forced toner consumption or when performing forced toner replenishment, correction may be performed using bulk density data or fluidity data.

  FIG. 2 shows a configuration example of the simulation calculation unit 200, and FIG. 3 shows an operation example thereof.

  The simulation calculation unit 200 may be provided in the image forming apparatus 100 or may be connected to the image forming apparatus 100 via a communication network. Each unit of the simulation calculation unit 200 is specifically implemented as a processing program, but at least a part thereof may be configured as a processing circuit. Similarly, the sensitivity correction amount determination unit 20 and the consumption correction amount determination unit 21 in FIG. 1 may also be connected to the image forming apparatus 100 via a communication network.

  2, the simulation calculation unit 200 includes a control unit 201, a data input unit 210, a model creation unit 220, a particle motion calculation unit 230, a data output unit 240, a characteristic evaluation unit 250, and the like. The data input unit 210 includes a particle data input unit 211, a region data input unit 212, an environment data input unit 213, and a calculation parameter input unit 214. The model creation unit 220 includes a particle data generation unit 221 and a boundary data generation unit 222. The particle motion calculation unit 230 includes an external force calculation unit 231 and a motion equation solving unit 232. The data output unit 240 includes a particle coordinate / velocity output unit 241 and a boundary load output unit 242. The characteristic evaluation unit 250 includes a bulk density calculation unit 251 and a fluidity calculation unit 252.

  The control unit 201 controls the entire processing of each unit (each program). The data input unit 210 receives information necessary for calculation from another device or input means provided separately (S10 in FIG. 3). In the particle data input unit 211, 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 and carrier to be calculated are calculated. Etc. are entered. In the region data input unit 212, the shape of the region in which the particle group moves, physical characteristics, mechanical characteristics, electrical characteristics, and the like are input. The environmental data input unit 213 inputs temperature / humidity information, time-lapse information, and in the example of the image forming apparatus, environmental information that affects the toner and carrier particle characteristics such as image density information. In addition to this, the calculation parameter input unit 214 is provided with information related to the number of calculation steps, time increment, data output method, and the like necessary for executing the calculation.

  The model creation unit 220 generates numerical data for particle motion calculation, and based on various information given by the particle data input unit 211 and the region data input unit 212, the particle or region to be analyzed 3 is determined (S11 in FIG. 3).

  The particle motion calculation unit 230 performs calculations for obtaining individual particle motions using the numerical data generated by the model creation unit 220 (S12 in FIG. 3). The general particle motion calculation method by the individual element method is, for example, “Hiroo Kiyama and Takashi Fujimura, Analysis of Gravity Flow of Rocky Granules Using Kandle's Discrete Rigid Element Method, Proc. ) 137-146 "or the like can be used. JP-A-10-260159, JP-A-10-260160, JP-A-11-214134, JP-A-2001-195386, JP-A-2002-109445, JP-A-2003-223049, JP-A-11 The calculation procedure in the case of assuming various applications such as -12165 and JP 20004-199271 may be used as appropriate.

In this method, the behavior of the particle group is determined by solving the equation of motion of the equation (1) for each particle. Therefore, first, the external force f on the right side is evaluated. As the external force, electromagnetic force is mainly applied when an electromagnetic field is applied, such as contact force between particles, gravity, adhesion force, centrifugal force, air resistance force, and the like.
mα = f Formula (1)

  If the external force is determined, the acceleration α is obtained from the mass m given in advance. Next, the velocity, displacement, and coordinates are obtained by numerically integrating the acceleration with respect to a predetermined time increment. If such a calculation is repeated for all the particles for a predetermined number of calculation steps, the behavior of the particle group can be obtained.

  The data output unit 240 is a part that transmits the calculation results obtained as needed to other devices. The particle coordinate / velocity output unit 241 receives the time-variation information on the coordinates and velocity of each particle as the boundary load output unit. In 242, a load acting on each boundary due to the contact of particles is output (S <b> 13 in FIG. 3).

  The characteristic evaluation unit 250 calculates various characteristics related to the performance as the image forming apparatus from the particle and boundary state obtained by the calculation (S14 in FIG. 3). The bulk density calculation unit 251 calculates the bulk density from the number of particles in a predetermined space, and the fluidity calculation unit 252 calculates the average moving speed of the particles and outputs it as an indicator of the flow state. The mixing ratio for each location can also be obtained from the number of toners and carriers.

  In this embodiment, a magnetic toner based on toner bulk density and fluidity, which has been conventionally controlled by substitution characteristics, by accurately calculating physical characteristics of toner particles over time by particle motion simulation. Correction accuracy of density sensor correction and toner supply amount correction can be improved. That is, it is possible to accurately correct toner density sensor sensitivity fluctuations due to changes in bulk density and fluidity. Alternatively, forcibly consuming and supplying the toner when the bulk and fluidity deteriorates can improve the deterioration of the bulk and fluidity, thereby preventing fluctuations in toner density sensor sensitivity. As a result, more stable toner density control is possible. In addition, it is possible to accurately correct fluctuations in toner replenishment amount due to changes in bulk density and fluidity. Alternatively, forcible toner consumption and supply when the bulk density and fluidity deteriorate can improve the deterioration of the bulk density and fluidity, thereby preventing fluctuations in the toner replenishment amount. As a result, more stable toner density control is possible. In addition, since there is no need for a measuring device for measuring the toner, the bulk of the developer, and the fluidity, there is no problem in size and cost.

  Next, another embodiment of the present invention will be described.

  FIG. 4 shows an embodiment in which the present invention is applied to an image forming apparatus of a type that performs toner replenishment control using an image density sensor. In this figure, parts corresponding to those in FIG. did.

  In this embodiment, an image density sensor 13d is provided around the photoreceptor 10, and the optical density of the toner reference patch provided on the surface of the photoreceptor 10 is detected. Based on the density output of the image density sensor 13d, the toner replenishment amount control unit 13c performs toner replenishment control so that the image density of the reference patch becomes a target value. Then, the density correction amount determination unit 20a determines the correction amount of the control system based on the image density based on the bulk density and fluidity, and supplies it to the toner replenishment amount control unit 13c to match the exact bulk density and fluidity. Control is performed.

  The density output of the image density sensor 13d can be used for charge potential control of the charging unit 11 and output level control of the exposure unit 12.

  Also in this embodiment, the toner bulk density and fluidity are calculated by particle motion simulation, the toner replenishment amount is corrected according to the calculated bulk density and fluidity, and a toner band for forced toner consumption is created. Forcible toner supply can be performed.

  In the example of FIG. 4, an example in which toner supply control is performed using the image density sensor 13 d has been described. However, so-called ICDC (Image Count Displace Control) is performed in which toner consumption is estimated from print image information. A similar type of image forming apparatus can be used. In this case, for example, as shown by a broken line in FIG. 4, the toner supply amount control unit 13c determines the supply amount from the toner consumption amount prediction unit information.

It is a figure which shows the structure of the Example of this invention as a whole. It is a figure explaining the structural example of the simulation calculation part of the above-mentioned Example. It is a figure explaining the operation example of the said simulation calculation part. It is a figure which shows the structure of the other Example of this invention as a whole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photoconductor 11 Charging unit 12 Exposure unit 13 Developing unit 13a Toner replenishment unit 13b Toner density sensor 13c Toner replenishment amount control unit 13d Image density sensor 14 Transfer unit 15 Cleaning unit 16 Paper transport mechanism 20 Sensitivity correction amount determination unit 20a Density correction amount Determination unit 21 Consumption correction amount determination unit 22 Remaining amount detection unit 100 Image forming apparatus 200 Simulation calculation unit 201 Control unit 210 Data input unit 211 Particle data input unit 212 Region data input unit 213 Environmental data input unit 214 Calculation parameter input unit 220 Model Creation unit 221 Particle data generation unit 222 Boundary data generation unit 230 Particle motion calculation unit 231 External force calculation unit 232 Motion equation solving unit 240 Data output unit 241 Particle coordinate / velocity output unit 242 Boundary load output unit 250 Characteristic evaluation Part 251 bulk density calculation unit 252 fluidity calculator

Claims (8)

Calculating means for simulating the temporal change and average velocity of the particle position for the toner particles based on the particle characteristics, the region characteristics and the environmental information;
A bulk density calculating means for calculating a bulk density from a time change of the particle position obtained from the simulation by the calculating means;
Fluidity calculating means for calculating the fluidity of the particles for development from the average speed obtained from the simulation by the calculating means;
An image forming apparatus comprising: a control system correcting unit that corrects an image forming control system based on the calculated bulk density and the fluidity.   2. The image formation control system corrected by the control system correction means includes a magnetic toner density sensor disposed in a developing unit, and the control system correction means corrects the sensitivity of the toner density sensor. The image forming apparatus described.   3. The image formation according to claim 1, wherein the image forming control system corrected by the control system correcting means includes a replenishing means for replenishing toner, and the control system correcting means corrects the replenishment amount control of the replenishing means. apparatus.   4. The image forming apparatus according to claim 1, further comprising a remaining amount estimating unit that estimates a remaining amount of developing particles, wherein the control system correcting unit corrects an estimated value of the remaining amount estimating unit.   The image forming apparatus according to claim 1, wherein the particle characteristics include a toner particle system, shape, density, charge, Young's modulus, Poisson's ratio, and friction coefficient.   The image forming apparatus according to claim 1, wherein the region characteristics include Young's modulus, Poisson's ratio, and friction coefficient of each member of the developing machine.   The image forming apparatus according to claim 1, wherein the environmental information includes time-dependent change information of the particle characteristics based on temperature and humidity, time, and image density information of the image. A step of simulating the temporal change and average velocity of the particle position of the toner particles based on the particle characteristics, the region characteristics and the environmental information by the calculation means;
A step of calculating a bulk density from a time change of the particle position obtained from a simulation by the calculation means by a bulk density calculation means;
A step of calculating the flowability of the particles for development from the average speed obtained from the simulation by the calculation means by the flowability calculation means;
And a step of correcting the control system for image formation based on the calculated bulk density and the fluidity by a control system correction unit.

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