JP2017223876A - Image forming apparatus, image forming method and image forming program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique of improving estimation accuracy of toner consumption in an electronicphotography in which development is performed in a photoreceptor having a high relative dielectric constant while suppressing end retention.SOLUTION: An image forming apparatus includes: a photoreceptor; an exposure section which exposes the photoreceptor with light to form an electrostatic latent image; an image forming section having a development section which bonds a toner onto the photoreceptor on the basis of the electrostatic latent image; a calibration section which performs calibration using at least one of a development bias potential of the development section and a dot area ratio; and a consumption prediction section which predicts consumption of a developer used for formation of an image on the basis of image data. The consumption prediction section predicts the consumption using the adjusted dot area ratio when the calibration is performed by adjusting the dot area ratio in a state in which the development bias potential is set to a limit value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus, an image forming method, and an image forming program.

  In an electrophotographic image forming apparatus, the amount of toner consumed in each printing is generally calculated based on image data. The toner consumption amount can be calculated based on the correlation between the toner consumption amount and the number of dots in the toner image. The calculation result of the toner consumption amount is used for controlling toner supply to the developing device, for example. As for the toner consumption calculation method, even if the data has the same number of dots, the toner consumption varies depending on the influence of the edge electric field. Techniques for improving accuracy by discriminating whether or not a pixel has been proposed (Patent Documents 1 and 2). On the other hand, Patent Document 3 proposes a technique for printing a solid image while suppressing edge accumulation when developing with an amorphous silicon photoconductor having a high relative dielectric constant.

JP 2009-198917 A JP 2013-20076 A JP, 2015-161704, A

  However, sufficient studies have not been made on estimation of toner consumption in electrophotography in which development is performed with a photoreceptor having a high relative dielectric constant while suppressing edge accumulation.

  The present invention has been made in view of such circumstances, and provides a technique for improving the estimation accuracy of toner consumption in electrophotography in which development is performed with a photoreceptor having a high relative dielectric constant while suppressing edge accumulation. For the purpose.

  The image forming apparatus of the present invention includes a photosensitive member, an exposure unit that exposes the photosensitive member to form an electrostatic latent image, and a developing unit that attaches toner to the photosensitive member based on the electrostatic latent image. An image forming unit, a calibration unit that performs calibration using at least one of the developing bias potential and the dot area ratio of the developing unit, and consumption of a developer used for forming an image based on image data A consumption prediction unit that predicts an amount, and the consumption prediction unit is configured to perform the calibration by adjusting the dot area ratio in a state where the development bias potential is set to a limit value. Predicts the consumption using the adjusted dot area rate.

  The image forming method of the present invention includes a photosensitive member, an exposure unit that exposes the photosensitive member to form an electrostatic latent image, and a developing unit that attaches toner to the photosensitive member based on the electrostatic latent image. An image forming process for forming an image using the image forming apparatus, a calibration process for performing calibration using at least one of the developing bias potential and the dot area ratio of the developing unit, and an image forming process based on image data. A consumption amount prediction step for predicting the consumption amount of the developer to be developed, and the consumption amount prediction step adjusts the dot area ratio in a state where the development bias potential is set to a limit value. Is performed, the method includes the step of predicting the consumption amount using the adjusted dot area ratio.

  The present invention provides an image forming unit including a photoconductor, an exposure unit that exposes the photoconductor to form an electrostatic latent image, and a developing unit that attaches toner to the photoconductor based on the electrostatic latent image. An image forming program for controlling an image forming apparatus having the above is provided. The image forming program includes: a calibration unit that performs calibration using at least one of a development bias potential and a dot area ratio of the development unit; and consumption of a developer used for image formation based on image data The image forming apparatus is caused to function as a consumption prediction unit that predicts the amount, and the calibration is performed by adjusting the dot area ratio in a state where the development bias potential is set to a limit value. If so, the consumption is predicted using the adjusted dot area rate.

  According to the present invention, it is possible to provide a technique for improving the estimation accuracy of toner consumption in electrophotography in which development is performed with a photoconductor having a high relative dielectric constant while suppressing edge accumulation.

2 is a block diagram illustrating a functional configuration of the image forming apparatus 1 according to an embodiment of the present disclosure. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus 1 according to an embodiment. FIG. 5 is a side cross-sectional view illustrating a structure of a developing unit 100k according to an embodiment. 4 is a flowchart showing the contents of a half patch calibration processing procedure of the image forming apparatus 1 according to an embodiment. 6 is a graph illustrating the contents of a toner amount table TD according to an embodiment. 6 is a graph for explaining the contents of correction in a toner amount table TD according to an embodiment. 10 is a graph for explaining the contents of a toner amount table TD according to a modification.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a functional configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 includes a control unit 10, an image forming unit 20, a storage unit 40, an image reading unit 50, and a fixing unit 80. The image reading unit 50 reads an image from a document and generates an image data ID that is digital data.

  The image forming unit 20 includes a color conversion processing unit 21, a halftone processing unit 22, a calibration density sensor 28, an exposure unit 29, and photosensitive drums (image carriers) 30c to 30k that are amorphous silicon photosensitive members. Development units 100c to 100k and charging units 25c to 25k. The color conversion processing unit 21 color-converts the image data ID, which is RGB data, into CMYK data. The halftone processing unit 22 performs halftone processing on the CMYK data to generate CMYK halftone data.

  The control unit 10 includes main storage means such as RAM and ROM, and control means such as MPU (Micro Processing Unit) and CPU (Central Processing Unit). The control unit 10 also has controller functions related to various I / O, USB (Universal Serial Bus), bus, and other hardware interfaces, and controls the entire image forming apparatus 1.

  The storage unit 40 is a storage device including a hard disk drive or a flash memory that is a non-temporary recording medium, and stores a control program and data for processing executed by the control unit 10. In the present embodiment, the storage unit 40 further stores calibration image data CD and a toner amount table TD.

  The calibration image data CD stores calibration image data CD for forming CMYK gradation calibration adjustment patches and CMYK half patches. The half patch is a patch that has a dot area ratio of less than 100% and represents a solid image. The reason why the solid image is expressed by the half patch is that an amorphous silicon photoconductor is used for the photoconductor drums 30c to 30k, as will be described in detail later.

  The toner amount table TD is also called a toner consumption amount table, and includes a table representing the relationship between the image data value and the toner consumption amount, and a correction coefficient. The toner amount table TD is used for calculating the toner consumption amount. The toner amount table TD includes a first toner amount table used when the dot area of a half patch representing a solid image is an initial value (70%), and a dot area of a half patch representing a solid image is 70%. The second toner amount table used when exceeding the upper limit and a correction table are included. The half patch is formed by forming a half latent image on the photosensitive drums 30c to 30k by the exposure unit 29.

  The dot area ratio means an area ratio occupied by dots when it is assumed that each dot has a preset area, and corresponds to the area ratio of the latent image in the half latent image. Actually, the dot size varies depending on, for example, a toner layer formation potential difference ΔV (described later) between the development bias potential Vslv and the magnetic roller potential Vmag, which corresponds to an area ratio (density) from an optical viewpoint. ) Is different. On the other hand, the solid density means a density at which the printing medium appears to be covered with dots without any gap from an optical viewpoint.

  FIG. 2 is a cross-sectional view illustrating the overall configuration of the image forming apparatus 1 according to the embodiment. The image forming apparatus 1 of the present embodiment is a tandem type color printer. In the image forming apparatus 1, photosensitive drums (image bearing members) 30m, 30c, 30y, and 30k are arranged in a row in the casing 70 so as to correspond to the respective colors of magenta, cyan, yellow, and black. Developing units 100m, 100c, 100y, and 100k are disposed adjacent to the photosensitive drums 30m, 30c, 30y, and 30k, respectively.

  The photosensitive drums 30m, 30c, 30y, and 30k are irradiated with laser beams Lm, Lc, Ly, and Lk for the respective colors from the exposure unit 29. By this irradiation, electrostatic latent images are formed on the photosensitive drums 30m, 30c, 30y, and 30k. The developing units 100m, 100c, 100y, and 100k attach the toner to the electrostatic latent images formed on the surfaces of the photosensitive drums 30m, 30c, 30y, and 30k while stirring the toner. Thereby, the developing process is completed, and toner images of the respective colors are formed on the surfaces of the photosensitive drums 30c to 30k.

  The image forming apparatus 1 has an endless intermediate transfer belt 27. The intermediate transfer belt 27 is stretched around the tension roller 24, the driving roller 26a, and the driven roller 26b. The intermediate transfer belt 27 is driven to circulate by the rotation of the driving roller 26a.

  For example, a black toner image on the photosensitive drum 30k is primarily transferred to the intermediate transfer belt 27 by sandwiching the intermediate transfer belt 27 between the photosensitive drum 30k and the primary transfer roller 23k, and the intermediate transfer belt 27 being driven to circulate. The The same applies to the three colors cyan, yellow, and magenta. A full color toner image is formed on the surface of the intermediate transfer belt 27 by performing primary transfer so as to be superimposed on each other at a predetermined timing. Thereafter, the full-color toner image is secondarily transferred to the printing paper P supplied from the paper feed cassette 60 and fixed on the printing paper P by the fixing roller pair 81 of the fixing unit 80.

  FIG. 3 is a side sectional view showing the structure of the developing unit 100k according to the embodiment of the present invention. The developing units 100m, 100c, and 100y have the same configuration as the developing unit 100k, and are also simply referred to as the developing unit 100. The developing unit 100 includes two agitating and conveying members 141 and 142, a magnetic roller 143, a developing roller (developer carrying member) 144, a developing container 145, and a regulating blade 146.

  The developing container 145 constitutes the outline of the developing unit 100. A partition portion 145 b is provided at the lower portion of the developing container 145. The partition unit 145b partitions the inside of the developing container 145 into a first transfer chamber 145a and a second transfer chamber 145c. The first transfer chamber 145a and the second transfer chamber 145c extend in a columnar shape in a direction perpendicular to FIG. 3, and contain a two-component developer (also simply referred to as a developer) made of a magnetic carrier and black toner.

  The developing container 145 further holds the magnetic roller 143 and the developing roller 144 rotatably. The developing container 145 has an opening 147 that exposes the developing roller 144 toward the photosensitive drum 30 (30k).

  The two agitating and conveying members 141 and 142 are cyclically moved while stirring the developer inside the first conveying chamber 145a and the second conveying chamber 145c, respectively. The stirring and conveying member 142 supplies the charged developer to the magnetic roller 143 as a magnetic brush. The magnetic roller 143 includes a nonmagnetic rotating sleeve 143a and a fixed magnet body 143b fixed inside the rotating sleeve 143a. The magnetic roller 143 and the developing roller 144 are opposed to each other with a predetermined clearance. The regulating blade 146 adjusts the magnetic brush to a predetermined height set in advance.

  The developing roller 144 has a non-magnetic developing sleeve 144a and a developing roller side magnetic pole 144b fixed inside the developing sleeve 144a. A magnetic roller potential Vmag is applied to the magnetic roller 143. A developing bias potential Vslv is applied to the developing roller 144. On the developing roller 144, a toner thin layer having a thickness corresponding to a toner layer forming potential difference ΔV between the developing bias potential Vslv and the magnetic roller potential Vmag is formed. Thus, since the thickness of the toner thin layer on the developing roller 144 varies according to the toner layer formation potential difference ΔV, the adjustment of the toner layer formation potential difference ΔV is used in the development bias calibration process (described later).

  The developing roller 144 forms a toner image on the surface of the photosensitive drum 30 through a facing portion (developing nip) having a predetermined clearance between the developing roller 144 and the photosensitive drum 30. The toner image is formed based on the potential difference between the electrostatic latent image potential on the surface of the photosensitive drum 30 and the developing bias potential Vslv applied to the developing roller 144.

  FIG. 4 is a flowchart showing the contents of the half patch calibration processing procedure of the image forming apparatus 1 according to the embodiment. In this embodiment, since the amorphous silicon photoconductors are used for the photoconductor drums 30c to 30k, the image forming apparatus 1 is configured to express a solid with a half patch in order to suppress the problem of the rear end accumulation. Yes.

  Amorphous silicon photoconductors have a characteristic that the relative permittivity is about three times higher than that of organic photoconductors (OPC), and the amount of toner that can be held by the photoconductor is large with respect to the development contrast voltage. For this reason, the amorphous silicon photoconductor can hold more toner than the solid density normally used. Therefore, when the amorphous silicon photoconductor is used in a saturated state, the amorphous silicon photoconductor is held exceeding the amount necessary for the solid density. Therefore, the amorphous silicon photoconductor is used in a non-saturated state even in the case of the solid density, and the solid density is determined when the toner formed on the developing roller 144 is almost completely developed on the photoconductor and the development is completed. May be used for

  However, the surface of the developing roller 144 in which toner is not consumed exists in the vicinity of the solid rear end portion during solid development. When the developing roller 144 rotates faster than the photosensitive drums 30c to 30k, the toner-unconsumed surface overtakes the rear end portion of the solid latent image on the amorphous silicon photosensitive member 30 at a nip portion (not shown). It will be. At this time, since the amorphous silicon photoconductor 30 is not saturated, the toner is further developed from the surface of the developing roller 144 where the toner is not consumed. By this development, a rear end accumulation becomes apparent as a solid density higher than the density assumed in advance.

  Furthermore, even in the reproduction of images such as characters and fine lines, the surface of the developing roller 144 where the toner is not consumed is present in the vicinity, so that a phenomenon in which the density becomes higher than the density assumed in advance occurs.

  Such a problem of rear end accumulation can be suppressed by expressing a solid with a half patch as disclosed in Patent Document 3. According to the half patch, for example, an electric field can be formed with a halftone latent image (half latent image). As a result, an amorphous silicon photoconductor can be used to form a sufficiently strong electric field (development contrast voltage) for development, and saturation can be achieved by attaching an appropriate amount of toner to the amorphous silicon photoconductor. Can do.

  The dot area ratio in the halftone dot latent image for realizing such a state is set in advance from the above viewpoint, and is assumed to be 70% in this example. However, sufficient adjustment may not be achieved with a dot area ratio of 70% only by adjusting the development contrast voltage. In such a case, the solid area density is realized by increasing the dot area ratio from 70%. However, according to the knowledge of the inventor, the problems such as the rear end accumulation described above become apparent again. Become.

  In step S10, the control unit 10 executes a development bias calibration process. In the developing bias calibration process, the control unit 10 controls the image forming unit 20 to form on the intermediate transfer belt 27 a chart having a plurality of half patches in which the toner layer forming potential difference ΔV is changed stepwise. In the present embodiment, the toner layer formation potential difference ΔV is changed by fixing the developing bias potential Vslv and adjusting the magnetic roller potential Vmag.

  Specifically, the control unit 10 includes a chart having a plurality of half patches in which the toner layer formation potential difference ΔV is stepwise different at a dot area ratio (70% in this example) as an initial value before calibration. 27. The plurality of half patches include those in which the toner layer formation potential difference ΔV is the maximum value (limit value).

  Using a plurality of half patches in which the toner layer formation potential difference ΔV is changed in stages specifies the toner layer formation potential difference ΔV that can form a toner thin layer having a sufficient thickness to form a solid toner image. Because. A plurality of half patches are formed for each of CMYK. Hereinafter, a cyan (C) half patch will be described as an example.

  The control unit 10 measures the density of the cyan (C) patch using the calibration density sensor 28. In the present embodiment, the calibration concentration sensor 28 emits infrared light from, for example, an LED (not shown), passes through a polarizing filter that transmits only P waves, and irradiates the patches with infrared P waves. The density is detected based on the ratio of the P wave and the S wave of the reflected light detected by the light receiving element. The calibration density sensor 28 includes a regular reflection method for detecting regular reflection light from the patch and a diffuse reflection method for detecting diffuse reflection light from the patch. The calibration density sensor 28 may measure the amount of red reflected light having a complementary color relationship of cyan (C).

  The controller 10 executes calibration of the toner layer formation potential difference ΔV. For calibration of the toner layer formation potential difference ΔV, for example, a patch that has reached a preset solid image target density from among a plurality of cyan (C) half patches whose toner layer formation potential difference ΔV is changed in stages. If it exists, it is executed by selecting the patch. Specifically, when there is a half patch having a patch density equal to or higher than a preset threshold, the control unit 10 determines the lowest toner layer formation potential difference ΔV among the half patches and the toner layer after calibration. The formation potential difference ΔV is set.

  In step S20, when the control unit 10 can calibrate within the adjustment range of the developing bias (bias controllable state), the control unit 10 proceeds to step S30 and cannot calibrate within the adjustment range of the toner layer formation potential difference ΔV. In the case (bias control impossible state), the process proceeds to step S30a. The case where half-patch calibration is not possible within the adjustment range of the development bias means that there is no patch that has reached a preset solid image target density from among a plurality of cyan (C) patches. ing.

  In general, one of the plurality of half patches reaches the solid image target density, but it has been confirmed by the present inventor that the solid image target density is not reached in a state where the toner charge amount is increased due to, for example, environmental fluctuation. .

  In step S30, the control unit 10 executes gamma correction calibration processing. The gamma correction calibration process is such that input / output characteristics are obtained such that the image density becomes a target value of the image forming apparatus 1 with respect to the input image data value of CMYK (in the above example, the data value of cyan). This is a calibration process for creating a table of output image data values (image density) with respect to input image data values.

  In step S40, the control unit 10 sets a dot area rate. Since calibration is possible within the adjustment range of the developing bias, the dot area ratio is set to 70% of the initial value.

  In step S50, the control unit 10 selects the first toner amount table. The first toner amount table is used for calculating toner consumption during printing in a bias controllable state. The first toner amount table is a table used when the dot area of a half patch representing a solid image is 70% of the initial value in a bias controllable state. The first toner amount table is used for calculating the consumption amount of toner consumed in printing of photographs and patches, and for calculating the consumption amount of toner consumed in printing characters and fine lines. And a character reference table.

  FIG. 5 is a graph for explaining the contents of the toner amount table TD according to the embodiment. FIG. 5 shows a photographic curve C1 representing the characteristics of the photographic table, a character reference curve C2 representing the characteristics of the character reference table, and a character representing a characteristic obtained by correcting the character reference table. A correction curve C3 is shown. These curves are obtained in advance by a product test or the like and statistically processed.

  In the bias control enabled state, the photo curve C1 and the character reference curve C2 are selected. As can be seen from FIG. 5, the photographic curve C1 and the character reference curve C2 have substantially the same characteristics. This is because in the bias controllable state, by using a half latent image, it is possible to achieve a saturated state by attaching an appropriate amount of toner to the amorphous silicon photoconductor.

  In step S60, the control unit 10 acquires calibration data. The calibration data includes a calibration value of the toner layer formation potential difference ΔV, a dot area ratio set to 70% of the initial value, and selection of the first toner amount table.

  On the other hand, in step S30a, the control unit 10 executes gamma correction calibration processing. The gamma correction calibration process in step S30a includes a process of setting the toner layer formation potential difference ΔV to the maximum value (limit value) within the adjustment range and increasing the dot area ratio from 70% to realize a solid density. This is different from the gamma correction calibration process in step S30, and is common in other points.

  Accordingly, since the dot area ratio is increased from 70%, a phenomenon in which the density becomes higher than a density assumed in advance, that is, a state in which the toner is consumed more than a quantity assumed in advance. Yes. This is because the dot area ratio is increased from 70%, and problems such as rear end accumulation become apparent again.

  In step S40a, the control unit 10 sets a dot area rate. In step S40a, the control unit 10 sets the toner layer formation potential difference ΔV to the maximum value within the adjustment range, and forms a plurality of half patches on the intermediate transfer belt 27 in which the dot area ratio is increased stepwise from 70%. The calibration density sensor 28 is used to set the dot area ratio AR (for example, 85%) that realizes a solid density.

  In step S41, the control unit 10 calculates a correction coefficient. The correction coefficient is a correction coefficient for compensating for an increase in toner consumption caused by problems such as rear end accumulation.

  FIG. 6 is a graph for explaining the contents of correction in the toner amount table TD according to the embodiment. FIG. 6A shows an enlarged view of the high image data side (near 70% to 100%) in FIG. FIG. 6B shows the relationship between the set dot area ratio and the correction coefficient C. The set dot area rate is the dot area rate set in step S40a (in this example, the dot area rate AR (85%)). The correction coefficient C is a ratio between the character reference curve C2 and the character correction curve C3 (C = character correction curve C3 / character reference curve C2).

  The correction coefficient C is calculated using the graph of FIG. In this example, since the dot area ratio AR is 85%, the correction coefficient C is 1.065. The character correction curve C3 is obtained by multiplying the correction coefficient C (1.065) when the image data value is 80% to 100%, and the correction coefficient C (1 to 1.065) when the image data value is 70% to 80%. And multiply. As a result, the correction curve for character C3 ensures continuity and corresponds to the development of surplus toner that occurs remarkably in printing characters and fine lines on the higher image data side in a state where bias control is impossible.

  In step S42, the control unit 10 executes a table creation process. In the table creation processing, the character correction curve C3 is the character reference curve C2 and the correction coefficient C (1 to 1.065 when the image data value is 70% to 80%, and 1 to 1.0 when the image data value is 80% to 100%. 065). The character correction curve C3 is created, for example, as a LUT (Look Up Table).

  In step S50a, the control unit 10 selects the second toner amount table. The second toner amount table is used for calculating toner consumption during printing in a state where bias control is impossible.

  The second toner amount table is a table used when the dot area of a half patch representing a solid image exceeds 70% in a state where bias control is impossible. The second toner amount table includes a photographic table (corresponding to the photographic curve C1) used for calculating the consumption amount of toner consumed for printing photographs and patches, and toner consumed for printing characters and fine lines. And a character correction table (corresponding to the character correction curve C3) used to calculate the consumption amount of.

  In step S60, the control unit 10 acquires calibration data. The calibration data includes a calibration value (maximum value as a limit value) of the toner layer formation potential difference ΔV, a dot area ratio set to the dot area ratio AR (85%), and selection of the second toner amount table. Contains. The calculation of the toner consumption is performed by the control unit 10 that functions as a consumption prediction unit.

  As described above, according to the image forming apparatus 1 according to the embodiment, in electrophotography in which development is performed with a photoconductor having a high relative dielectric constant while suppressing edge accumulation, the image is generated when images such as characters and fine lines are reproduced. The toner consumption amount can be estimated in consideration of toner consumption caused by factors such as adhesion of excess toner to the photoreceptor and edge accumulation. Thereby, it is possible to optimize the display of the remaining toner amount and the toner replenishment.

  The present invention can be implemented not only in the above embodiment but also in the following modifications.

  Modification 1: In the above embodiment, the toner layer formation potential difference ΔV is calibrated by adjusting the magnetic roller potential Vmag of the developing units 100c to 100k, and the dot area ratio is adjusted when the magnetic roller potential Vmag cannot be calibrated. And proofreading. However, the calibration is not limited to the magnetic roller potential Vmag or the dot area ratio, and may be calibrated by adjusting the light amount of exposure by the exposure unit 29. Further, the change of the toner layer formation potential difference ΔV is not limited to the adjustment of only the magnetic roller potential Vmag, but can be realized by adjusting at least one of the magnetic roller potential Vmag and the developing bias potential Vslv.

  However, when calibrating by adjusting the amount of exposure light, it is preferable to use the adjustment of the amount of exposure light prior to the dot area ratio for calibration. In the present invention, regardless of the amount of exposure light, when the calibration cannot be performed by adjusting the toner layer formation potential difference ΔV, the dot area ratio is adjusted for calibration.

  Modification 2: In the above embodiment, the character correction curve C3 is created from the character reference curve C2 using the correction coefficient C. However, the present invention is not limited to this method, and the character correction curve can be obtained by other methods. C3 can be created. Specifically, for example, a character correction curve C4 having a dot area ratio AR (100%) is prepared in advance, and the character correction curve C4 having a dot area ratio AR (100%) is between the character reference curve C2 and the character correction curve C4. The character correction curve C3 may be created by interpolation processing by interpolation. Furthermore, the reference curve is not limited to two, but three or more may be prepared in advance, and interpolation processing by interpolation may be executed in a section between adjacent curves.

  Modification 3: In the above embodiment, the method for measuring the amount of toner consumption is not specifically described, but it can also be measured by, for example, a device or a permeability sensor that can measure the amount of toner dropped from the toner container. However, since these methods measure changes in toner amount over a long period of time, they cannot be used in real time. However, verification and correction of the photographic curve C1, the character reference curve C2, and the character correction curve C3 are not possible. Is available.

  Modification 4: In the above embodiment, an amorphous silicon photoconductor is used, but the present invention is not limited to the use of an amorphous silicon photoconductor. The present invention can be applied to an image forming apparatus that reproduces a solid density with a photoreceptor having a generally high relative dielectric constant.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Control part 20 Image forming part 21 Color conversion process part 28 Calibration density sensor 29 Exposure part 40 Storage part 50 Image reading part 60 Paper feed cassette 70 Case

Claims (6)

An image forming apparatus,
An image forming unit having a photoconductor, an exposure unit that exposes the photoconductor to form an electrostatic latent image, and a developing unit that attaches toner to the photoconductor based on the electrostatic latent image;
A calibration unit that performs calibration using at least one of the development bias potential and the dot area ratio of the development unit;
A consumption prediction unit that predicts the consumption of developer used for forming an image based on image data;
With
The consumption amount prediction unit uses the adjusted dot area rate when the calibration is performed by adjusting the dot area rate in a state where the development bias potential is set to a limit value. An image forming apparatus that predicts the consumption. The image forming apparatus according to claim 1,
When the calibration is performed by adjusting the developing bias potential, the consumption amount prediction unit uses the first toner amount table that represents the relationship between the image data and the consumption amount, and uses the consumption amount prediction unit. When the calibration is performed by adjusting the dot area rate, the correction value determined using the adjusted dot area rate and the first toner amount table are used. An image forming apparatus that predicts the consumption amount. The image forming apparatus according to claim 1, wherein
The image forming unit includes an intermediate transfer belt that transfers a toner image from the photoconductor,
The image forming apparatus having a density sensor that measures the density of the plurality of half patches formed on the intermediate transfer belt. The image forming apparatus according to any one of claims 1 to 3,
The photoconductor is an amorphous silicon photoconductor,
The amorphous silicon photoconductor is an image forming apparatus that forms the solid image in a non-saturated state. An image forming method comprising:
An image that forms an image using a photoconductor, an exposure unit that exposes the photoconductor to form an electrostatic latent image, and a developing unit that attaches toner to the photoconductor based on the electrostatic latent image Forming process;
A calibration step of performing calibration using at least one of the development bias potential and the dot area ratio of the development unit;
A consumption prediction step for predicting the consumption of the developer used to form the image based on the image data;
With
The consumption prediction step uses the adjusted dot area ratio when the calibration is performed by adjusting the dot area ratio in a state where the development bias potential is set to a limit value. An image forming method including a step of predicting the consumption. Image formation having a photoconductor, an exposure unit that exposes the photoconductor to form an electrostatic latent image, and a developing unit that attaches toner to the photoconductor based on the electrostatic latent image An image forming program for controlling an apparatus,
The image forming program includes:
A calibration unit that performs calibration using at least one of the development bias potential and the dot area ratio of the development unit, and a consumption amount that predicts a consumption amount of a developer used for forming an image based on image data Causing the image forming apparatus to function as a prediction unit;
The consumption amount prediction unit uses the adjusted dot area rate when the calibration is performed by adjusting the dot area rate in a state where the development bias potential is set to a limit value. An image forming program for predicting the consumption.