JP2009020481A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of more correctly predicting arrival timing of an error that a waste toner container is full of waste toner. <P>SOLUTION: A main control section 100 is configured to calculate the quantity of transfer residue of normally charged toner being the quantity of transfer residue of normally charged toner on a photoreceptor surface, on the basis of at least image formation sent from outside and the coefficient of normally charged toner being the coefficient of normally charged toner charged to a normal polarity, and to calculate the quantity of transfer residue of reversely charged toner, on the basis of at least the coefficient of reversely charged toner being the coefficient of toner charged to a polarity reverse to the normal polarity, and to calculate the result of the addition of the quantity of transfer residue of normally charged toner and the quantity of transfer residue of reversely charged toner as the quantity of toner remaining on the photoreceptor surface after passing through a primary transfer nip. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides an image forming apparatus such as a copying machine, a facsimile machine, a printer, or the like having a calculating means for calculating the amount of transfer residual toner remaining on the surface of the latent image carrier after passing through the transfer process based on image information. It relates to the device.

  Conventionally, as this type of image forming apparatus, the one described in Patent Document 1 is known. In this image forming apparatus, an electrostatic latent image formed on the surface of a drum-shaped photoconductor as a latent image carrier is developed by a developing device, and then the obtained toner image is transferred from the photoconductor to a recording sheet as a transfer body. . Then, the transfer residual toner remaining on the surface of the photoconductor after passing through the transfer process is removed by a scraping blade and then stored in a waste toner container. Also, based on the cumulative count result of the number of pixels of the output image, the amount of residual toner generated on the surface of the photoconductor is calculated, and whether or not the waste toner container is full based on the cumulative result. Determine. According to such a configuration, it is possible to reduce the size and cost of the apparatus by determining the timing of the full error of the waste toner container without using toner detection means such as an optical sensor for detecting the toner in the waste toner container. Can be planned. In particular, in a configuration in which toner images of different colors formed on a plurality of photoconductors are superimposed on a transfer body to obtain a color image, by omitting toner detection means of a plurality of waste toner containers corresponding to each photoconductor, The effect of downsizing and low cost is increased.

JP-A-2-293886

  However, a full error occurs in the waste toner container and the waste toner overflows from the waste toner container before determining that the toner accommodation amount in the waste toner container is full based on the accumulation of the residual transfer toner amount. There was a thing.

  Therefore, the present inventors have conducted intensive research on the cause of the problem, and have found the following. That is, in the developing device, most of the toner particles contained in the toner are normally charged toner particles that are charged to the normal charge polarity, but there are also a few reversely charged toner particles that are charged to a polarity opposite to the normal charge polarity. Occur. The reversely charged toner particles cause not only an electrostatic latent image on the photoreceptor but also a so-called fogging phenomenon that adheres to a background portion that should not be attached. In a normal apparatus, most of the reversely charged toner particles that cause fogging on the background remain on the photosensitive member without being transferred to the transfer member. Then, it is removed from the photoreceptor as transfer residual toner and collected in a waste toner container. In the conventional image forming apparatus, since the amount of residual toner due to fog is not taken into account, the theoretically generated amount of residual toner is less than the actual generated amount. This is the cause of the actual full error occurring before the timing for determining that the full error has occurred based on the accumulated amount of residual toner.

  The present invention has been made in view of the above background, and an object of the present invention is to provide an image forming apparatus capable of more accurately predicting the arrival timing of a waste toner full error.

To achieve the above object, the invention of claim 1 comprises a latent image carrier for carrying a latent image on its surface, a latent image writing means for writing a latent image on the surface based on image information, A developing unit that develops the latent image by attaching toner to the latent image on the surface; a transfer unit that transfers the toner image obtained on the surface by development to a transfer member; and In an image forming apparatus comprising a calculating means for calculating the amount of toner remaining on the surface after passing through a transfer step by a transfer means, at least the image information and a coefficient relating to a normally charged toner charged to a normal polarity The normal charge toner transfer remaining amount that is the remaining transfer amount of the normal charge toner is calculated on the basis of the normal charge toner coefficient, and at least a coefficient related to the reverse charge toner charged to a polarity opposite to the normal polarity. Some reverse charge Based on the toner coefficient, a reverse charge toner transfer remaining amount that is a transfer remaining amount of the reverse charge toner is calculated, and an addition result of the normal charge toner transfer remaining amount and the reverse charge toner transfer remaining amount is calculated as the transfer step. The calculation means is configured to calculate the amount of toner remaining on the surface of the latent image carrier after passing through.
According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the normal charging is performed based on at least the number or area of pixels of the latent image calculated based on the image information and the normal charging toner coefficient. The calculating means is configured to calculate the remaining amount of toner transfer and to calculate the remaining amount of reversely charged toner based on at least the surface movement distance of the latent image carrier and the reversely charged toner coefficient. It is characterized by that.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, at least the development toner amount prediction value per latent image pixel and the normal charge toner transfer rate prediction value as the normal charge toner coefficient. Alternatively, the residual rate prediction value is used, and as the reverse charge toner coefficient, at least the toner adhesion amount prediction value of the reverse charge toner per unit surface moving distance of the latent image carrier and the transfer rate prediction value of the reverse charge toner Or the said calculation means was comprised so that a residual rate prediction value might be used, It is characterized by the above-mentioned.
According to a fourth aspect of the present invention, in the image forming apparatus of the first aspect, the non-image of the latent image carrier is based on the image information and a coefficient relating to the reversely charged toner as the reversely charged toner transfer remaining amount. The above calculation means is configured to calculate the reversely charged toner transfer remaining amount of the part.
According to a fifth aspect of the present invention, in the image forming apparatus of the fourth aspect, the normal charging is performed based on at least the number or area of pixels of the latent image calculated based on the image information and the normal charging toner coefficient. The toner transfer remaining amount is calculated, and the reversely charged toner transfer remaining amount is calculated based on at least the number or area of pixels of the non-image portion calculated based on the image information and the reversely charged toner coefficient. Thus, the calculation means is configured as described above.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, the number of pixels of the non-image portion includes a cumulative total number of pixels while the latent image carrier is rotating, and the image information. The area of the non-image portion is calculated based on the cumulative total area during rotation of the latent image carrier and the image information. The calculation means is configured to calculate based on the area of the latent image calculated based on the above.
According to a seventh aspect of the present invention, in the image forming apparatus according to the fourth, fifth, or sixth aspect, the number of pixels of the non-image portion is a cumulative total number of pixels while the latent image carrier is rotating. The area of the non-image portion is calculated by subtracting the area of the latent image from the accumulated total area while the latent image carrier is rotating. Thus, the calculation means is configured as described above.
The invention according to claim 8 is the image forming apparatus according to any one of claims 4, 5, 6 or 7,
As the normal charge toner coefficient, at least a development toner amount prediction value per pixel of the latent image and a transfer rate prediction value or a residual ratio prediction value of the normal charge toner are used, and as the reverse charge toner coefficient, at least, The calculation means is configured to use the toner adhesion amount predicted value of the reversely charged toner per pixel of the non-image portion of the latent image carrier and the transfer rate predicted value or the residual rate predicted value of the reversely charged toner. It is a feature.
According to a ninth aspect of the present invention, the reverse charge toner transfer rate prediction value is lower than the normal charge toner transfer rate prediction value, or the reverse charge toner residual rate prediction value is used. As described above, the calculation means is configured to use a value higher than the predicted value of the remaining rate of the normally charged toner.
The invention of claim 10 is the image forming apparatus according to claim 3, 8 or 9,
Predicted development toner amount value, transfer rate prediction value of normally charged toner, predicted remaining rate of normally charged toner, predicted toner adhesion amount, predicted transfer rate of reversely charged toner, and remaining rate of reversely charged toner The calculation means is configured to change at least one of the predicted values over time.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, the predicted transfer rate of the reversely charged toner is lowered or the reverse charge is increased as the cumulative operating time of the developing unit increases. The calculation means is configured to increase the toner residual ratio prediction value.
According to a twelfth aspect of the present invention, in the image forming apparatus according to the tenth or eleventh aspect, the transfer rate predicted value of the normally charged toner is lowered as the cumulative operation time of the developing unit increases, or The calculation means is configured so as to increase the residual charge prediction value of the normally charged toner.
According to a thirteenth aspect of the present invention, in the image forming apparatus according to any one of the third, eighth, ninth, tenth, eleventh, or twelfth aspects, an environment detection unit that detects at least one of temperature and humidity is provided. Predicted developing toner amount, predicted transfer rate of normally charged toner, predicted remaining rate of normally charged toner, predicted toner adhesion amount, predicted transfer rate of reversely charged toner, and predicted remaining rate of reversely charged toner The calculation unit is configured to change at least one of the two based on the detection result of the environment detection unit.
According to a fourteenth aspect of the present invention, in the image forming apparatus according to the thirteenth aspect, as the temperature or humidity detection result increases, the predicted transfer rate of the reversely charged toner is lowered, or the reversely charged The calculation means is configured to increase the toner residual ratio prediction value.
According to a fifteenth aspect of the present invention, in the image forming apparatus according to the thirteenth or fourteenth aspect, the predicted transfer rate of the normally charged toner is lowered as the temperature or humidity detection result increases, or The calculation means is configured so as to increase the residual charge prediction value of the normally charged toner.
According to a sixteenth aspect of the invention, there is provided the image forming apparatus according to any one of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth and fifteenth aspects. Removal means for removing the transfer residual toner remaining on the surface of the latent image carrier after passing through the transfer step by the transfer means, and waste toner containing the transfer residual toner removed by the removal means as waste toner The waste toner storage means is provided on a common holding body together with at least one of the latent image carrier and the developing means, and is integrally attached to and detached from the main body of the image forming apparatus. It is characterized by being made possible.

  In these inventions, in addition to calculating the transfer residual toner amount by the normally charged toner that can normally adhere to the latent image of the latent image carrier, not only the latent image of the latent image carrier but also the background portion. By calculating the amount of residual toner due to reversely charged toner adhering, the arrival timing of waste toner full error can be predicted more accurately than in the past, which did not take into account the latter amount of residual toner. Can do.

Next, a first embodiment of an electrophotographic color laser printer (hereinafter simply referred to as a printer) will be described as an image forming apparatus to which the present invention is applied.
First, the basic configuration of the printer according to the first embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating the printer according to the first embodiment. The printer includes four process units 1Y, 1M, 1C, and 1K for forming toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K). Also provided are an optical writing unit 50, a paper feed cassette 51, a paper feed path 53, a registration roller pair 54, a transfer unit 60, a fixing device 80, a paper discharge roller pair 55, a stack unit 56, and the like. Note that the subscripts Y, M, C, and K of the respective symbols indicate members for yellow, magenta, cyan, and black, respectively.

  The optical writing unit 50 serving as a latent image writing means includes a light source composed of four laser diodes (not shown) corresponding to each color of Y, M, C, and K, a regular hexahedral polygon mirror, and a polygon for rotationally driving the mirror. A motor, an fθ lens, a lens, a reflection mirror, and the like are included. The laser beam L emitted from the laser diode reaches one of four photoconductors to be described later while being deflected by a polygon mirror. As a result, the surfaces of the four photoconductors are optically scanned in the dark.

  FIG. 2 is an enlarged configuration diagram showing the K process unit 1K among the four process units 1Y, 1M, 1C, and 1K. In the figure, a process unit 1K includes a photosensitive member 3K, a charging device 5K, a developing device 10K, a drum cleaning device 20K, and the like disposed around the photosensitive member 3K. Then, they are held in a common casing (holding body) as a single unit and are integrally attached to and detached from the printer main body.

  The photosensitive member 3K has an organic photosensitive layer coated on the peripheral surface of a drum-shaped element tube made of aluminum or the like, and is driven to rotate in the clockwise direction in the drawing at a predetermined linear velocity by a driving means (not shown).

  The charging device 5K includes a charging roller 6K that is driven to rotate while being in contact with or close to the photoreceptor 3K, a charging cleaning roller 7K that rotates while being in contact with the charging roller 6K, a charging cleaning blade 8K that is in contact with the charging roller 6K. Then, by causing a discharge between the charging roller 6K to which a charging bias is applied by a power source (not shown) and the photosensitive member 3K, the surface of the photosensitive member 3K has a negative polarity that is the same polarity as the normal charging polarity of the K toner. Charge uniformly. K toner may adhere to the charging roller 6K at a position facing the photosensitive member 3K, but it is transferred to the charging cleaning roller 7K to which a cleaning bias is applied by a power source (not shown). Then, it is scraped off from the charging cleaning roller 7K by the charging cleaning blade 8K and stored in a toner storage portion provided in the casing of the charging device 5K. Since the amount of K toner transferred from the photosensitive member 3K to the charging roller 6K is very small, the toner storage portion of the charging device 5K will not be filled before the end of the life of the process unit 1K.

  In this printer, the charging device 5K employs a method using a charging roller 6K. However, a charging device using a charging brush or a scorotron method may be employed.

  An electrostatic latent image for K is formed on the surface of the photoreceptor 3K uniformly charged by the charging device 5K by optical scanning by the optical writing unit (50) described above. The electrostatic latent image is developed into a K toner image by the developing device 10K.

  The developing device 10K includes a developing roller 11K that is rotationally driven while exposing a part of its peripheral surface from an opening provided on a side surface of the casing. Further, a toner supply roller 12K that rotates while contacting the developing roller 11K, a thinning blade 13K, a toner container 14K, a stirring member 15K, and the like are also provided.

  K toner (not shown) is stored in the toner storage portion 14K. The K toner is agitated by the agitating member 15K disposed in the toner accommodating portion 14K. The stirring member 15K sends the toner toward a toner supply roller 12K described later.

  The toner supply roller 12K has a cored bar and a toner carrying layer made of foam such as urethane foam coated on the surface thereof, and is driven to rotate in the counter direction with the developing roller 11K by a driving means (not shown). Is done. Then, after the K toner sent from the stirring member 15K is taken into the foam cell of the toner carrying layer, it is supplied to the surface of the developing roller 11K at a contact position with the developing roller 11K described later.

  The developing roller 11K includes a cored bar and an elastic layer coated on the surface of the developing roller 11K. The developing roller 11K is rotatably supported by a bearing (not shown) while being rotated in a counterclockwise direction in the figure by a driving unit (not shown). Is done. The K toner supplied from the toner supply roller 12K is carried on the surface of the elastic layer. Accordingly, the K toner layer formed on the surface of the developing roller 11K enters the contact portion between the thinning blade 13K and the developing roller 11K as the developing roller 11K rotates. Then, after the layer is thinned by the thinning blade 13K or the frictional electrification of the K toner particles is promoted, it is sent to the developing area where the developing roller 11K and the photosensitive member 3K are in contact.

  A developing bias is applied to the developing roller 11K by a power source (not shown). This developing bias is a negative polarity DC voltage or a superimposed voltage in which an AC voltage is superimposed on a negative polarity DC voltage. In any case, the DC voltage is a negative polarity electrostatic latent image of the photosensitive member 3K. And a value smaller than the background portion (uniformly charged portion) of the photoreceptor 3K. In the development area, the negatively charged K toner is transferred to the electrostatic latent image on the photoreceptor 3K. As a result, the electrostatic latent image is developed into a K toner image.

  The K toner image developed in this manner is sent to the primary transfer nip where the photosensitive member 3K and an intermediate transfer belt 61 described later come into contact with the rotation of the photosensitive member 3K. Primary transfer is performed on the front surface.

  The printer employs a one-component developing type developing device 10K that uses a one-component developer mainly composed of toner as a developer, but two-component development mainly composed of toner and a magnetic carrier. You may employ | adopt the developing device of the 2 component developing system using an agent.

  Untransferred toner that has not been transferred to the intermediate transfer belt 61, which is a transfer body, adheres to the surface of the photoreceptor 3K that has passed through the primary transfer nip. This transfer residual toner is removed from the photoreceptor 3K by the drum cleaning device 20K.

  The drum cleaning device 20K serves as a removing unit that scrapes off the transfer residual toner from the photoconductor 3K while contacting the surface of the photoconductor 3K before passing the position facing the charging device 5K after passing through the primary transfer nip. The cleaning blade 21K is provided. Further, it also has a waste toner storage unit 22K as waste toner storage means for storing the transfer residual toner after scraping.

  The transfer residual toner on the surface of the photoconductor 3K is scraped off from the photoconductor 3K by the cleaning blade 21K of the drum cleaning device 20K and then stored in the waste toner storage unit 22K. The process unit 1K is replaced with a new one when any of the devices inside it reaches the end of its life. However, depending on variations in the durability of each product and frequent print quality, the process unit 1K is discarded before the end of its life. The toner storage unit 22K may become full. In such a case, the unit is replaced with a new unit as the lifetime.

  The surface of the photoreceptor 3K from which the transfer residual toner has been cleaned by the drum cleaning device 20K is subjected to charge removal processing by a charge removal lamp (not shown) and then uniformly charged by the charging device 5K.

  FIG. 3 is an enlarged perspective view showing the K process unit 1K. On the outer surface of the casing of the process unit 1K, a memory tag 25K equipped with a nonvolatile memory (flash memory) as data storage means is fixed. In a state where the process unit 1K is mounted on the printer main body, the memory tag 25K and a main control unit (not shown) of the printer main body (details will be described later) are electrically connected via a contact (not shown). Then, information in the nonvolatile memory is read by the main control unit, or information is written into the nonvolatile memory by the main control unit. In the nonvolatile memory, information necessary for maintenance and management of the process unit includes unit ID, date of manufacture, date of start of use, number of unit recycles, number of times of printing operation, cumulative surface moving distance of the photoreceptor, waste toner Cumulative amount, full error capacity, etc. are stored. Instead of the memory tag 25K, a printed board on which an IC chip or a non-contact type IC chip is mounted may be employed.

  Of the four process units 1Y, 1M, 1C, and 1K shown in FIG. 1, the unit for K has been described with reference to FIGS. 2 and 3, but the process units 1M, C, and K for other colors are also described. Since it is the same structure, description is abbreviate | omitted.

  In FIG. 1 described above, a transfer unit 60 is disposed below the process units 1Y, M, C, and K for the respective colors. The transfer unit 60 moves the endless intermediate transfer 61 endlessly in the counterclockwise direction in the drawing while being stretched by a plurality of stretching rollers. Specifically, the plurality of stretching rollers are a driving roller 62, a secondary transfer roller 63, a cleaning backup roller 64, and four primary transfer rollers 65Y, M, C, and K. In addition to these, the transfer unit 60 also includes a bracket (not shown) that rotatably supports each roller at both ends, a secondary transfer nip roller 66 disposed outside the belt loop, and the like.

  Examples of the material of the intermediate transfer belt 61 include resin materials such as polyvinylidene fluoride, polyimide, polycarbonate, and polyethylene terephthalate. These resin materials are molded into a seamless belt and used. However, it is desirable not to use the resin material as it is, but to adjust the electrical resistance by dispersing a conductive material such as carbon black. Moreover, a surface layer or the like may be laminated on a belt base by molding these resin materials into a seamless belt shape by a method such as spraying or dipping.

  The drive roller 62, the secondary transfer roller 63, the cleaning backup roller 64, and the four primary transfer rollers 65Y, 65M, 65C, 65K are all in contact with the back surface (loop inner peripheral surface) of the intermediate transfer belt 61.

  The four primary transfer rollers 65Y, 65M, 65C, and 65K are rollers in which a metal cored bar is covered with an elastic material such as sponge or rubber, and the Y, M, C, and K photoconductors 3Y, M, and K are rollers. The intermediate transfer belt 61 is sandwiched between the photoreceptor and the photosensitive member by being pressed toward C and K. As a result, the four primary bodies for Y, M, C, and K in which the four photoreceptors 3Y, M, C, and K and the front surface of the intermediate transfer belt 61 are in contact with each other with a predetermined length in the belt moving direction. A transfer nip is formed.

  A transfer bias controlled at a constant current by a transfer bias power source (not shown) is applied to the cores of the four primary transfer rollers 65Y, 65M, 65C, 65K. As a result, a transfer charge is applied to the back surface of the intermediate transfer belt 61 via the four primary transfer rollers 65Y, 65M, 65C, 65K, and the intermediate transfer belt 61 and the photoreceptors 3Y, M, C in each primary transfer nip. , K, a primary transfer electric field is formed. By the primary transfer electric field, Y, M, C, and K toner images on the photoreceptors 3Y, 3M, 3C, and 3K are transferred onto the front surface of the intermediate transfer belt 61 so as to overlap each other. As a result, a four-color superimposed toner image is formed on the front surface of the intermediate transfer belt 61.

  In this printer, primary transfer rollers 65Y, 65M, 65C, and 65, which will be described later, are provided as means for forming a transfer electric field. However, instead of the rollers, brushes, blades, and the like are provided. May be used. A transfer charger or the like may be used.

  Of the entire area in the circumferential direction of the intermediate transfer belt 61, the secondary transfer nip roller 66 disposed outside the belt loop is connected to the belt by the secondary transfer nip roller 66 disposed outside the belt loop. Abuts from the front side. As a result, a secondary transfer nip where the front surface of the intermediate transfer belt 61 and the secondary transfer nip roller 66 abut is formed.

  The secondary transfer roller 63 disposed inside the belt loop is applied with a secondary transfer bias having a negative polarity that is constant-current controlled by a power source (not shown). In contrast, the secondary transfer nip roller 66 disposed outside the belt loop is grounded. Then, between the secondary transfer roller 63 and the secondary transfer nip roller 66, a four-color superimposed toner image made of negative polarity toner is statically moved from the secondary transfer roller 63 side to the secondary transfer nip roller 66 side. A secondary transfer electric field to be electromoved is formed.

  The four-color superimposed toner image formed on the front surface of the intermediate transfer belt 61 enters the secondary transfer nip as the belt moves endlessly.

  A paper feed cassette 51 is disposed at the bottom of the printer body. The paper feed cassette 51 stores a plurality of recording papers P in a bundle of sheets, and presses the paper feeding roller 51a against the uppermost recording paper P. Then, the sheet feeding roller 51 a is rotated at a predetermined timing, and the recording sheet P is sent out to the sheet feeding path 53.

  In the middle of the paper feed path 53, a pair of registration rollers 54 is disposed, and both rollers are driven to rotate in order to sandwich the recording paper P sent from the paper feed cassette 51 between the rollers. As soon as the leading edge of the paper P is sandwiched, the rotational drive of both rollers is stopped. Then, the recording paper P is sent out toward the secondary transfer nip at a timing when the recording paper P can be synchronized with a four-color superimposed toner image on the intermediate transfer belt 61 at a secondary transfer nip described later.

  On the recording paper P sandwiched in the secondary transfer nip, the four-color superimposed toner image on the intermediate transfer belt 61 is secondarily transferred collectively by the action of the secondary transfer electric field and nip pressure described above. Then, a full color toner image is formed in combination with the white color of the recording paper P.

  Of the four primary transfer rollers 65Y, 65M, 65C, and 65K, three for Y, M, and C are each supported by a swing bracket (not shown) via a bearing (not shown). The swing bracket can swing about a rotation shaft (not shown). By this swing, the three primary transfer rollers 65Y, 65M, 65C move, and the tension posture of the intermediate transfer belt 61 becomes a posture in which the belt is brought into contact with only the K photoconductor 3K. The posture may be in contact with each of the two photoconductors 3Y, 3M, 3C, and 3K.

  This printer performs the following printing operation when printing out a full-color image. That is, when full-color image data (image information) sent from an external personal computer (not shown) or the like is received, the four photosensitive members 3Y, 3M, 3C are moved to the intermediate transfer belt 61 by driving the swing bracket described above. , K are driven to rotate in the clockwise direction in the drawing while taking the posture of bringing all of K and K into contact. Then, Y, M, C, and K toner images are formed on the photoreceptors 3Y, 3M, 3C, and 3K, and a four-color superimposed toner image is formed on the front surface of the intermediate transfer belt 61 by superimposing them. . Next, the four-color superimposed toner image is collectively transferred onto the recording paper P at the secondary transfer nip, and then the recording paper P is sent to the fixing device 80.

  The fixing device 80 forms a fixing nip by the contact between the pressure roller 82 and a fixing roller 81 containing a heat source such as a halogen lamp, and fixes the recording paper P sent from the secondary transfer nip. Insert into the nip. Then, the full color toner image is fixed on the surface of the recording paper P by the action of heating and pressurization in the nip. The recording paper P subjected to the fixing process in this way passes through the paper discharge roller pair 55 and is then discharged from the printer housing and stacked on the stack portion on the top surface of the housing.

  In the continuous print mode in which images are continuously formed on a plurality of recording papers P, a full color image is continuously printed on each of the plurality of recording papers P by repeating the processes described so far.

  The printer performs the following printing operation when printing out a monochrome image. That is, when monochrome image data (image information) sent from an external personal computer (not shown) or the like is received, the four photosensitive members 3Y, 3M, 3M, Of C and K, only the photoconductor 3K for K is rotated in the clockwise direction in the drawing while taking the posture of contacting only the photoconductor 3K for K. In the case of a monochrome image, primary transfer is not performed at the transfer nips for Y, M, and C, so that the transfer nips are not formed. As a result, a monochrome image can be printed out without imposing an extra load on the intermediate transfer belt 61, the process units 1Y, M, and C (particularly the photosensitive member) other than those for K, and the drive system thereof.

  When driving of the K photoconductor 3K and the intermediate transfer belt 61 is started, a K toner image is formed on the photoconductor 3K by the K process unit 1K. Then, the recording paper P is sent out from the registration roller pair 54 at a predetermined timing while performing primary transfer alone on the intermediate transfer belt 61. Next, after the K toner image on the intermediate transfer belt 61 is secondarily transferred to the recording paper P at the secondary transfer nip, a fixing process or the like is performed in the same manner as in the formation of a full-color image.

  In this printer having the above basic configuration, the transfer unit 60 is an intermediate transfer that serves as a transfer body for Y, M, C, and K toner images obtained on the surfaces of the photoreceptors 3Y, M, C, and K by development. It functions as a transfer means for transferring to the belt 61. The method of transferring the toner image from the photosensitive member to the recording paper P via the intermediate transfer belt 61 has been described. However, the method of directly superimposing and transferring the toner image from the photosensitive member to the recording paper P as the transfer member. May be adopted.

Next, a characteristic configuration of the printer will be described.
FIG. 4 is a block diagram showing a part of the electric circuit of the printer. In the figure, a main control unit 100 functions as a control unit that controls driving of each device in the printer. In the figure, only the optical writing control unit 150 and the process units 1Y, M, C, and K for each color are shown as devices electrically connected to the main control unit 100 for convenience. In addition, various devices are connected to the main control unit 100. For convenience, only the memory tags 25Y, M, C, and K are shown as constituent elements of the process units 1Y, M, C, and K of the respective colors. Various devices (such as sensors) are connected to the main control unit 100.

  The optical writing control unit 150 controls driving of the optical writing unit (50) shown in FIG. 1, and includes an interface 151, an image information storage unit 152 including a RAM (Random Access Memory), a CPU (Central Processing Unit) 153 and the like. Then, the image information sent from a personal computer or the like outside the printer is acquired by the interface 151 and then temporarily stored in the image information storage unit 152. Next, writing data for each color is generated based on the acquired image information, and driving of the laser diodes and polygon motors for each color is controlled based on this data and a synchronization signal sent from the main control unit 100. To do.

  The main control unit 100 includes a CPU 101, a first RAM 102, a second RAM 103, a third RAM 104, a ROM (Read Only Memory) 105, and the like. And based on the control program memorize | stored in ROM105, each apparatus is controlled or various arithmetic processing is performed. Further, as described above, various information stored in the memory tag 25K of the process units 1Y, 1M, 1C, and 1K is read and various information is written to the memory tag 25K.

  The writing data for each color generated by the optical writing control unit 150 is sent from the optical writing control unit 150 to the main control unit 100. The main control unit 100 calculates the number of output dots (number of output pixels) of each color (Y, M, C, K) per sheet based on the write data, and displays the calculation result. Based on this, the amount of residual toner for each color per sheet is calculated.

  More specifically, the main control unit 100 for each of Y, M, C, and K, the development toner amount prediction value K1 for one dot of the latent image, the normal charge toner residual rate prediction value K2, and the unit surface movement of the photoreceptor. The ROM 105 stores a toner adhesion amount predicted value K3 of reversely charged toner, a residual rate predicted value K4 of reversely charged toner, a 1 dot adhesion amount predicted value K5 of reversely charged toner, and the like per distance.

  The development toner amount prediction value K1 is a prediction value of the toner adhesion amount from the development roller to the photosensitive member per dot. Further, the estimated remaining rate K2 of the normally charged toner is a prediction of the remaining rate of the normally charged toner (minus charged toner in this example) attached to the electrostatic latent image on the surface of the photoreceptor at the primary transfer nip. If this value is 100 [%], no transfer residual toner is generated. Further, the toner adhesion amount predicted value K3 of the reversely charged toner per unit surface movement distance of the photoconductor is the reversely charged toner from the developing roller to the photoconductor generated when the photoconductor moves on the surface by 1 [mm] due to its rotation. It is the adhesion amount prediction value. Since the adhesion of the reversely charged toner (in this example, plus charge) occurs not only on the latent image portion of the photoconductor but also on the background portion, the amount of the toner does not distinguish between the latent image and the background portion. It is possible to calculate based on the moving distance. The reverse charge toner residual ratio prediction value K4 is a predicted value of the residual ratio of the reverse charge toner adhering to the photoconductor on the surface of the photoconductor in the primary transfer nip. Also, the 1-dot toner adhesion amount predicted value K5 of the reversely charged toner is a predicted value of the reversely charged toner adhesion amount per dot of the latent image on the photosensitive member. These predicted values are obtained by a prior experiment using a printer testing machine.

  The toner adhesion amount predicted value K3 of the reversely charged toner per unit surface movement distance of the photoreceptor and the 1 dot adhesion amount predicted value K5 of the reversely charged toner are obtained as follows. That is, a printer testing machine having the configuration shown in FIG. 1 is prepared. However, in each color process unit of the printer testing machine, the waste toner container of the drum cleaning device is a small bag made of an adhesive tape. The transfer unit 60 is removed from the printer tester having such a configuration. In each color process unit, the developing device is idled without performing optical writing on the uniformly charged photoreceptor. Then, the entire circumference of the photoconductor becomes a background portion, and the reversely charged toner contained in the toner in the developing device adheres to the background portion. The reversely charged toner is collected in the aforementioned sachet. After performing this operation for a predetermined time, the pouch is removed from the drum cleaning device. Then, after the delicate toner adhering to the cleaning blade and the photosensitive member is collected by the adhesive tape, the weight of the sachet and the adhesive tape is measured. Next, after subtracting the weight of the sachet and adhesive tape in the initial state from the measured value to determine the recovered toner amount, it is divided by the photoreceptor surface travel distance over the entire operation time, so that reverse charging per unit surface travel distance is achieved. A predicted toner adhesion amount K3 of the toner is obtained. Further, by dividing the toner adhesion amount predicted value K3 by the total number of dots per unit surface moving distance, a one-dot adhesion amount predicted value K5 of the reversely charged toner is obtained.

  Further, the remaining rate prediction value K4 of the reversely charged toner is obtained as follows. That is, the transfer unit 60 is set in the printer test machine described above, and the same operation as when the estimated amount of toner adhesion of the reversely charged toner is measured is performed for a predetermined time. However, at this time, the primary transfer bias is applied to the primary transfer rollers 65Y, 65M, 65C, 65K for each color. Then, after measuring the weight of the transfer residual toner collected in the sachet and the adhesive tape, the measurement result is divided by the toner adhesion amount prediction value of the reversely charged toner obtained in advance to obtain the residual rate prediction value K4. obtain. The reversely charged toner residual ratio prediction value K4 obtained in this way is about 70% in the printer testing machine used by the present inventors, although it depends on the apparatus configuration.

  Further, the predicted development toner amount K1 per dot is obtained as follows. That is, the transfer unit 60 is removed from the printer test machine. Then, while continuously developing the entire solid test image in the developable area of the photoconductor (the area facing the developing roller), the operation of collecting the toner in the above-described sachet is performed for a predetermined time. . Then, after measuring the amount of toner collected in the sachet and the adhesive tape, the result is divided by the total number of dots output during operation to obtain a predicted development toner amount per dot. However, the developed toner amount prediction value K1 includes the amount of adhesion due to the normally charged toner and the amount of adhesion due to the reversely charged toner. In the present invention, it is necessary to distinguish between the two, but for the purpose of improving the measurement accuracy, the regular charged toner and the reverse charged toner are not distinguished in units of one dot. Accordingly, the development toner amount prediction value K1 per dot includes both the regular charged toner and the reversely charged toner. Then, the developed toner amount per printer obtained based on the developed toner amount predicted value K1 is corrected later to a value corresponding only to the normally charged toner. The correction method will be described later.

  Further, the remaining rate prediction value K2 of the normally charged toner is obtained as follows. That is, in the above-described measurement, the amount of toner collected corresponding to the total number of dots output during operation includes those due to regular charged toner and those due to reverse charged toner. Therefore, the amount of toner charged corresponding to the total number of dots is subtracted from the amount of adhesion of the reversely charged toner corresponding to the total number of dots (a value based on the predicted toner adhesion amount K3) to obtain the normal charged toner recovery amount. Next, the transfer unit 60 is set in the printer test machine described above, and the same operation as when the predicted toner amount K1 is measured is performed for a predetermined time. At this time, primary transfer bias is applied to the primary transfer rollers 65Y, 65M, 65C, 65K for each color. Then, the weight of the transfer residual toner collected in the sachet and the adhesive tape is measured. Since this measurement result also includes both the normally charged toner and the reversely charged toner, the transfer remaining amount by the reversely charged toner (value based on the transfer remaining amount of the reversely charged toner and the remaining rate prediction value K4) is subtracted from the measurement result. . Then, the subtraction result is divided by the above-mentioned regular charged toner collection amount to obtain a regular charge toner residual rate prediction value K4. The residual charge prediction value K4 of the normally charged toner obtained in this manner is about 10% in the printer tester used by the present inventors, although it depends on the apparatus configuration.

  For each color of Y, M, C, and K, the main control unit 100 calculates the amount of developed toner per dot stored in the ROM 105 to the number of output dots per print calculated from the above writing data. By multiplying the predicted value K1, a developing toner amount Mg1 per print is calculated. As described above, since this calculation result includes both the normally charged toner and the reversely charged toner, a value corresponding to only the normally charged toner is obtained by correction. Specifically, by multiplying the one-dot adhesion amount predicted value K5 of the reversely charged toner stored in the ROM by the number of output dots per one print, the reversely charged toner in the image portion of one print is printed. Calculate the amount of adhesion. Then, the developing toner amount Mg1 per print is corrected by subtraction of the calculation result.

  Next, the main control unit 100 multiplies the corrected development toner amount cumulative value Mg1 by the normal charge toner remaining rate prediction value K2 stored in the ROM 105, thereby transferring the transfer charge of the normal charge toner per print sheet. The amount M1 is calculated. Then, the transfer remaining amount accumulated value Mrb of the normally charged toner stored in the first RAM 102 is updated by adding the calculation result.

  Thereafter, the main control unit 100 calculates the surface movement distance of the photoconductor required for each print and the toner adhesion amount prediction value K3 of the reversely charged toner per unit surface movement distance of the photoconductor stored in the ROM 105. By multiplying, the amount of reversely charged toner per print is calculated. Then, by multiplying the calculation result by the reverse charge toner residual rate prediction value K4 stored in the ROM 105, the transfer remaining amount M2 of reverse charge toner per print is obtained. Furthermore, the transfer remaining amount cumulative value Mrc of the reversely charged toner stored in the second RAM 103 is updated by adding the transfer remaining amount M2.

  After updating the transfer remaining amount accumulated values (Mrb, Mrc) of the normally charged toner and the reversely charged toner in this way, the waste toner accumulated amount Mra is calculated by adding the two, and then stored in the third RAM 104. The accumulated amount of waste toner Mra until then is updated to the same value as the calculation result. What should be noted here is that the conventional image forming apparatus calculates only the transfer remaining amount accumulated value Mrb of the normally charged toner as the accumulated amount of waste toner, but this printer and the transfer of the reversely charged toner in this printer. The total of the remaining amount accumulated value Mrc is the waste toner accumulated amount Mra. In such a configuration, the waste toner cumulative amount Mra can be obtained more accurately than in the case where only the transfer remaining amount cumulative value Mrb of the normally charged toner is used as the waste toner cumulative amount.

  In addition, instead of setting the sum of the transfer remaining amount accumulated value Mrb of the normally charged toner and the transfer remaining amount accumulated value Mrc of the reversely charged toner as the waste toner accumulated amount Mra, the transfer remaining amount per print sheet is set as the normally charged toner. When both of the reversely charged toners are obtained, the total of them may be added to the waste toner cumulative amount Mra so far.

  Further, when the main control unit 100 functioning as a calculation unit obtains the accumulated amount of waste toner Mra for each color, the main controller 100 and the waste of the drum cleaning device stored in the memory tag (25Y, M, C, K). The full error capacity in the toner container is compared. Then, based on the comparison result, it is determined whether or not a full error has occurred in the waste toner container in each color process unit. Specifically, when the calculated waste toner cumulative amount Mra is equal to or greater than the full error capacity, it is determined that a full error has occurred. When a full error occurs, a message to that effect is displayed on a display unit such as a display (not shown) serving as notification means. You may alert | report a message by the method different from a display, such as the output of a sound and a character image.

  A series of control routines as described above are performed for each color for each print sheet, so that waste toner is accommodated without providing a toner detection sensor for each color in the process unit for each color. It is possible to appropriately determine whether there is a full error in the copy.

  It should be noted that the transfer rate prediction value may be stored instead of storing the remaining rate prediction value (K2, K4) of the regular charge toner or the reverse charge toner in the ROM 105. The predicted transfer rate is a predicted transfer rate of toner from the photoconductor to the intermediate transfer belt 61. If the transfer rate prediction value is subtracted from 100 [%], the residual rate prediction value is obtained. Therefore, the residual rate prediction value may be obtained by such calculation.

  Further, since the surface moving distance of the photoconductor and the driving time are strictly correlated, the driving time of the photoconductor substantially corresponds to the surface moving distance. Therefore, by adjusting the development toner amount prediction value K1 and the reversely charged toner adhesion amount prediction value K3, the transfer remaining amount of the regular charge toner and the reverse charge toner can be determined based on the driving time which is a substantial surface moving distance. It is also possible to ask for it.

  In addition, the main control unit 100 updates the number of printing operations in the memory tag for each print by adding 1, or updates the accumulated surface movement distance of the photoconductor in the memory tag by adding a predetermined value. To do. Further, the calculated accumulated amount of waste toner for each color is stored not only in the third RAM 104 but also in the memory tags (25Y, M, C, K). As a result, even if the replaced process unit is a used product that has been used halfway, the accumulated amount of waste toner thereafter can be accurately obtained based on the data in the memory tag.

  In this printer, the waste toner storage units are provided in the process units 1Y, 1M, 1C, and 1K of each color, but the waste toner is transported from the drum cleaning device of each color unit to a common waste toner container outside the unit. A configuration may be adopted. In this case, the accumulated amount of individual waste toner for each color may be obtained and the sum of them may be used to determine whether the waste toner container is full.

Next, each example in which a more characteristic configuration is added to the printer according to the first embodiment will be described. Unless otherwise specified below, the configuration of the printer according to each example is the same as that of the first embodiment.
[First embodiment]
As described above, the process units 1Y, 1M, 1C, and 1K of the respective colors are replaced when it is assumed that the entire unit has reached the end of its life when any of the mounted devices has reached the end of its life. Further, even when the toner stored in the developing device runs out, it is considered that the entire unit has reached the end of its life and is replaced. As described above, since the process units 1Y, 1M, 1C, and 1K for each color are not supplied with new toner in the developing device, a relatively large amount of toner is accommodated in the developing device in the initial state. is doing. Even when the toner is only stored in the toner storage unit before being supplied to the toner supply roller, the toner is continuously stirred by the stirring member when the printing operation is performed. Due to this agitation, the toner in the toner accommodating portion is deteriorated as the cumulative operation time of the developing device increases. It is known that as the toner deteriorates, the residual rate of the regular charged toner and the reversely charged toner gradually increases (the transfer rate gradually decreases). For this reason, as the cumulative operation time of the process unit increases, the residual rate predicted value (or transfer rate predicted value) of the regular charged toner and the reverse charged toner stored in the ROM 105 gradually moves away from an appropriate value. Go. As a result, the calculation accuracy of the accumulated amount of waste toner gradually decreases.

Therefore, in the printer according to the first embodiment, as the cumulative operating time of the developing device increases, the residual rate prediction values (K2, K4) of the normally charged toner and the reversely charged toner are gradually increased. It has become. Specifically, in the present printer, the main control unit 100 stores the accumulated surface moving distance of the photosensitive member in the above-described memory tag for each of the process units 1Y, M, C, and K of each color. Since this printer is designed so that the photosensitive member is not driven independently of the developing device, the cumulative surface movement distance of the photosensitive member has a strict correlation with the cumulative operating time of the developing device. Therefore, the main control unit 100 stores the data table shown in the following Table 1 in the ROM 105. Based on this data table, the remaining rate prediction values (K2, K4) are gradually increased as the cumulative surface movement distance of the photoconductor stored in the memory tag increases.

  With such a configuration, it is possible to reduce inappropriate detection timing of a full error due to deterioration of toner over time.

  FIG. 5 is a flowchart illustrating a processing flow of the calculation process of the accumulated amount of waste toner performed by the main control unit 100 of the printer. This processing flow is performed individually for each color process unit. When the main control unit 100 starts the calculation process, the main control unit 100 first waits for the progress of the flow until the end of the single-sheet print job (step 1: hereinafter, step is denoted as S), and then stored in the memory tag. The cumulative surface moving distance D of the photoconductor is updated (S2). Next, the normal charge toner residual rate prediction value K2 and the reverse charge toner residual rate prediction value K4 corresponding to the cumulative surface moving distance D are specified from the data table in the ROM 105 (S3). Then, after calculating the developing toner amount Mg1 per printed sheet based on the number of output dots and the like (S4), the developing toner amount Mg1 is corrected by subtracting the reversely charged toner adhesion amount per sheet (S5). Thereafter, the remaining amount M1 of the normally charged toner per sheet is calculated by multiplying the developed toner amount Mg1 by the estimated remaining rate K2 of the normally charged toner (S6), and then the normally charged toner is calculated by adding the calculation results. The transfer remaining amount accumulated value Mrb is updated (S7).

  After the transfer remaining amount accumulated value Mrb is updated in this way, the surface movement distance D1 of the photosensitive member required for one print and the toner adhesion amount prediction value K3 of the reversely charged toner per unit surface movement distance Is applied to calculate the adhesion amount Mx of the reversely charged toner per print. Then, a transfer remaining amount M2 of the reversely charged toner per print is obtained by multiplying the calculation result by the predicted remaining rate K4 of the reversely charged toner (S8). Further, the transfer remaining amount cumulative value Mrc of the reversely charged toner is updated by adding the transfer remaining amount M2 (S9).

  Finally, a waste toner accumulation amount Mra is calculated by adding the transfer remaining amount accumulated value Mrb of the normally charged toner and the transfer remaining amount accumulated value Mrc of the reversely charged toner (S10), and the calculation result is stored in the third RAM 104 or the memory tag. Write (S11).

  It should be noted that instead of the remaining rate prediction values K2 and K4, the transfer rate prediction values of the normally charged toner and the reversely charged toner may be used, and a process of decreasing the accumulated surface moving distance D as the cumulative surface moving distance D increases may be executed. Good.

[Second Embodiment]
In general, it is known that the residual rate of regular charged toner and reversely charged toner gradually increases (transfer rate gradually decreases) as humidity and temperature rise. This is because the resistance of the toner resin itself and the developing roller decreases, and the charge amount tends to decrease on the high-temperature and high-humidity side, and the ratio of the reversely charged toner increases. For this reason, when the humidity and temperature change, the appropriate value of the residual rate also changes accordingly. Nevertheless, if a constant value is used as the residual rate, the calculation accuracy of the accumulated amount of waste toner is lowered due to changes in humidity and temperature.

Therefore, in the printer according to the second embodiment, a humidity sensor (not shown) is provided, and the detection result is output to the main control unit 100. The main control unit 100 is configured to gradually increase the residual rate prediction values (K2, K4) of the normally charged toner and the reversely charged toner as the humidity increases. Specifically, the main control unit 100 stores a data table shown in Table 2 below in the ROM 105. Based on this data table, the residual rate prediction values (K2, K4) are gradually increased as the humidity detection result increases.

  With such a configuration, it is possible to reduce improper detection timing of a full error due to humidity fluctuations. Note that the main control unit 100 may be configured to increase the residual rate prediction values (K2, K4) as the detection result of the temperature sensor increases. Alternatively, the transfer rate prediction value may be used instead of the remaining rate prediction value (K2, K4), and the main control unit 100 may be configured to lower the transfer rate prediction value as the humidity or temperature increases. .

  FIG. 6 is a flowchart illustrating a processing flow of the calculation process of the accumulated amount of waste toner performed by the main control unit 100 of the printer. This processing flow is also performed individually for each color process unit. When starting the calculation process, the main control unit 100 first waits for the progress of the flow until one print job is completed (S1), and then acquires the humidity detection result from the humidity sensor (S2). Next, the remaining rate prediction value K2 of the normally charged toner corresponding to the humidity and the remaining rate prediction value K4 of the reversely charged toner are specified from the data table in the ROM 105 (S3). Thereafter, the waste toner cumulative amount Mra is calculated in the same manner as the flow after S4 in FIG.

Next, a second embodiment of a printer to which the present invention is applied will be described.
In the printer of the first embodiment, when many image patterns with many latent image portions and few background portions are mixed, the accumulated amount of waste toner is erroneously calculated more than the actual amount of waste toner, and is still full. In some cases, a waste toner container that has not been filled is determined to be full. The present inventors have conducted intensive research on the cause of such problems, and have found the following. As waste toner in the waste toner container, there is more reversely charged toner than regular charged toner adhering to the image area, and in order to detect the fullness of waste toner more accurately, the transfer remaining amount of reversely charged toner is accurate. Need to be calculated. Further, the adhesion of the reversely charged toner occurs on the background portion, and a very small amount adheres to the latent image portion. Furthermore, since the amount of the reversely charged toner adhering to the background portion is greatly influenced by the number of pixels or the area of the background portion, the amount of the reversely charged toner greatly differs between a pattern with a large background portion and a small pattern. In the printer according to the first embodiment, the remaining amount of the reversely charged toner is calculated based on the surface movement distance of the photosensitive member and the reversely charged toner coefficient, and the influence of the number of pixels or the area of the background portion is taken into consideration. Absent. Therefore, depending on the image pattern, the reversely charged toner adhesion amount cannot be accurately predicted, and as a result, an error occurs in the reversely charged toner transfer remaining amount on the surface of the photoreceptor. Specifically, in a pattern with many latent image portions and few background portions, the calculated reversely charged toner transfer remaining amount is larger than the actual reversely charged toner transfer remaining amount.

  As described above, the adhesion of the reversely charged toner occurs on the background portion of the photoreceptor, and the amount of the adhesion to the latent image portion is negligible, so that the level becomes negligible. Therefore, it is preferable to apply the estimated adhesion amount of the reversely charged toner only to the background portion. Therefore, in the second embodiment, the remaining charge of the reversely charged toner is calculated based on the image information and the reversely charged toner coefficient. As in the first embodiment, the remaining amount of normal toner transferred is calculated based on the image information and the normally charged toner coefficient. Then, the remaining toner transfer amount on the photosensitive member surface is calculated from the calculated normal toner transfer remaining amount attached to the latent image portion and the reversely charged toner transfer remaining amount attached to the background portion. In this way, the remaining charge transfer amount of the reversely charged toner is also calculated in consideration of the image pattern, so that the remaining transfer amount of the reversely charged toner can be calculated more accurately, thereby more accurately transferring the remaining toner amount on the surface of the photosensitive member. Is calculated.

  The characteristic configuration of the printer of the second embodiment will be described below. The configuration of the printer according to the second embodiment is the same as that of the first embodiment except for the more characteristic configuration described below, and a description thereof will be omitted.

  The printer according to the second embodiment includes the electric circuit shown in the block diagram of FIG. 4. The main control unit 100 selects each color (Y, Y) for each print based on the write data. The number of output dots (number of output pixels) of M, C, and K) is calculated, and the transfer residual toner amount of each color per sheet is calculated based on the calculation result.

  For each of Y, M, C, and K, the main control unit 100 predicts the developed toner amount K1 for one dot of the latent image, the estimated remaining rate K2 of the regular charged toner, the unit surface moving distance of the photosensitive member, and the main scanning. In the ROM 105, a toner adhesion amount predicted value K3 of reversely charged toner, a residual rate predicted value K4 of reversely charged toner, a one dot adhesion amount predicted value K5 of reversely charged toner, and the like are stored.

  The development toner amount prediction value K1 is a prediction value of the toner adhesion amount from the development roller to the photosensitive member per dot. Further, the estimated remaining rate K2 of the normally charged toner is a prediction of the remaining rate of the normally charged toner (minus charged toner in this example) attached to the electrostatic latent image on the surface of the photoreceptor at the primary transfer nip. If this value is 100 [%], no transfer residual toner is generated. The toner adhesion amount predicted value K3 of the reversely charged toner per unit surface movement distance of the photoconductor is a non-image portion from the developing roller to the photoconductor generated when the surface of the photoconductor moves by 1 [mm] due to its rotation. This is a predicted value of the amount of negatively charged toner attached to the toner. As described above, the adhesion of the reversely charged toner (plus charge in this example) occurs on the background portion of the photoconductor, and the amount of the adhesion to the latent image portion is negligible. Therefore, the estimated adhesion amount of the reversely charged toner is applied only to the non-image portion. The reverse charge toner residual ratio prediction value K4 is a predicted value of the residual ratio of the reverse charge toner adhering to the photoconductor on the surface of the photoconductor in the primary transfer nip. Further, the one-dot toner adhesion amount predicted value K5 of the reversely charged toner can be easily calculated by dividing the reversely charged toner adhesion amount predicted value per unit surface movement distance obtained by K3 by the total number of dots per unit surface movement distance. Can be requested. These predicted values are obtained by a prior experiment using a printer testing machine.

  The toner adhesion amount predicted value K3 of the reversely charged toner per unit surface movement distance of the photoreceptor and the 1 dot adhesion amount predicted value K5 of the reversely charged toner are obtained as follows. That is, a printer testing machine having the configuration shown in FIG. 1 is prepared. However, in each color process unit of the printer testing machine, the waste toner container of the drum cleaning device is a small bag made of an adhesive tape. The transfer unit 60 is removed from the printer tester having such a configuration. In each color process unit, the developing device is idled without performing optical writing on the uniformly charged photoreceptor. Then, the entire circumference of the photoconductor becomes a background portion, and the reversely charged toner contained in the toner in the developing device adheres to the background portion. The reversely charged toner is collected in the aforementioned sachet. After performing this operation for a predetermined time, the pouch is removed from the drum cleaning device. Then, after the delicate toner adhering to the cleaning blade and the photosensitive member is collected by the adhesive tape, the weight of the sachet and the adhesive tape is measured. Next, after subtracting the weight of the sachet and adhesive tape in the initial state from the measured value to determine the recovered toner amount, it is divided by the photoreceptor surface travel distance over the entire operation time, so that reverse charging per unit surface travel distance is achieved. A predicted toner adhesion amount K3 of the toner is obtained. Further, by dividing the toner adhesion amount predicted value K3 by the total number of dots per unit surface moving distance, a one-dot adhesion amount predicted value K5 of the reversely charged toner is obtained.

  Further, the remaining rate prediction value K4 of the reversely charged toner is obtained as follows. That is, the transfer unit 60 is set in the printer test machine described above, and the same operation as when the estimated amount of toner adhesion of the reversely charged toner is measured is performed for a predetermined time. However, at this time, the primary transfer bias is applied to the primary transfer rollers 65Y, 65M, 65C, 65K for each color. Then, after measuring the weight of the transfer residual toner collected in the sachet and the adhesive tape, the measurement result is divided by the toner adhesion amount prediction value of the reversely charged toner obtained in advance to obtain the residual rate prediction value K4. obtain. The reversely charged toner residual ratio prediction value K4 obtained in this way is about 70% in the printer testing machine used by the present inventors, although it depends on the apparatus configuration.

  Further, the predicted development toner amount K1 per dot is obtained as follows. That is, the transfer unit 60 is removed from the printer test machine. Then, while continuously developing the entire solid test image in the developable area of the photoconductor (the area facing the developing roller), the operation of collecting the toner in the above-described sachet is performed for a predetermined time. . Then, after measuring the amount of toner collected in the sachet and the adhesive tape, the number of dots in the non-image area for a predetermined time is calculated. The calculation formula can be easily obtained by subtracting the number of dots for an image printed at a predetermined time from the product of the total number of dots per unit surface movement distance and the photosensitive body travel distance for a predetermined time. By accumulating the obtained number of dots in the non-image area and the previously estimated 1-dot toner adhesion amount K5 of the reversely charged toner, the amount of toner in the non-image area corresponding to the required time can be obtained. Therefore, the amount of developed toner per dot is obtained by subtracting the amount of toner in the non-image area from the amount of toner collected in the sachet and adhesive tape, and dividing the result by the number of dots output in the printing section during operation. Get the predicted value. The predicted developed toner amount K1 can also be obtained by stopping the machine during solid printing, obtaining a solid image on the photoreceptor by suction, and dividing by the number of dots.

Further, the remaining rate prediction value K2 of the normally charged toner is obtained as follows. That is, in the above-described measurement, the remaining amount prediction value K4 of the reversely charged toner is added to the toner amount of the non-image portion for the required time to obtain the toner recovery amount of the non-image portion. Further, the developing toner amount in the image portion is calculated by integrating the predicted developing toner amount K1 per dot and the total number of dots in the image portion.
Next, the transfer unit 60 is set in the printer test machine described above, and the same operation as when the predicted toner amount K1 is measured is performed for a predetermined time. At this time, primary transfer bias is applied to the primary transfer rollers 65Y, 65M, 65C, 65K for each color. Then, the weight of the transfer residual toner collected in the sachet and the adhesive tape is measured. This measurement result also includes both the normally charged toner and the reversely charged toner. Therefore, by subtracting the toner recovery amount of the non-image area obtained earlier, the toner recovery amount of the image area by the normally charged toner is obtained. . The toner collection amount is divided by the developing toner amount of the image portion to obtain a remaining charge prediction value K4 of the normally charged toner. The residual charge prediction value K4 of the normally charged toner obtained in this manner is about 5% in the printer tester used by the present inventors, although it depends on the apparatus configuration. Further, the estimated remaining rate K2 of the normally charged toner is obtained by stopping the machine during solid printing and sucking the solid images before and after transfer on the photosensitive member (solid image after transfer per desired area). / (Solid image before transfer per desired area) is also possible.

  For each color of Y, M, C, and K, the main control unit 100 calculates the amount of developed toner per dot stored in the ROM 105 to the number of output dots per print calculated from the above writing data. By multiplying the predicted value K1, a developing toner amount Mg1 per print is calculated.

  Next, the main control unit 100 multiplies the development toner amount cumulative value Mg1 by the normal charge toner remaining rate prediction value K2 stored in the ROM 105 to obtain the normal charge toner transfer remaining amount M1 per print. calculate. Then, the transfer remaining amount accumulated value Mrb of the normally charged toner stored in the first RAM 102 is updated by adding the calculation result.

  Thereafter, the main control unit 100 subtracts the number of output dots per print calculated from the above-mentioned writing data from the total number of dots obtained by multiplying the surface movement distance of the photosensitive member by the number of dots per unit distance. Then, the number of dots in the non-image portion is obtained, and the number of dots in the non-image portion and the amount of reversely charged toner per print are calculated by integration with the one-dot toner adhesion amount predicted value K5 of the reversely charged toner. Then, by multiplying the calculation result by the reverse charge toner residual rate prediction value K4 stored in the ROM 105, the transfer remaining amount M2 of reverse charge toner per print is obtained. Furthermore, the transfer remaining amount cumulative value Mrc of the reversely charged toner stored in the second RAM 103 is updated by adding the transfer remaining amount M2.

  After updating the transfer remaining amount accumulated values (Mrb, Mrc) of the normally charged toner and the reversely charged toner in this way, the waste toner accumulated amount Mra is calculated by adding the two, and then stored in the third RAM 104. The accumulated amount of waste toner Mra until then is updated to the same value as the calculation result. What should be noted here is that the conventional image forming apparatus calculates only the accumulated remaining toner amount Mrb of the normally charged toner as the accumulated amount of waste toner. The total of the cumulative value Mrc is the waste toner cumulative amount Mra. In such a configuration, the waste toner cumulative amount Mra can be obtained more accurately than in the case where only the transfer remaining amount cumulative value Mrb of the normally charged toner is used as the waste toner cumulative amount. Further, by calculating the transfer remaining amount accumulated value Mrc of the reversely charged toner in consideration of the number of dots in the non-image portion, the value of the accumulated remaining amount Mrc of the reversely charged toner becomes an image pattern having a large or small image area. Therefore, the accumulated amount of waste toner Mra can be obtained more accurately.

  In addition, instead of setting the sum of the transfer remaining amount accumulated value Mrb of the normally charged toner and the transfer remaining amount accumulated value Mrc of the reversely charged toner as the waste toner accumulated amount Mra, the transfer remaining amount per print sheet is set as the normally charged toner. When both of the reversely charged toners are obtained, the total of them may be added to the waste toner cumulative amount Mra so far.

  Further, when the main control unit 100 functioning as a calculation unit obtains the accumulated amount of waste toner Mra for each color, the main control unit 100 compares the full error capacity in the waste toner container in the same manner as in the first embodiment, and fills up. Determine the error. A series of control routines as described above are performed for each color for each print sheet, so that waste toner is accommodated without providing a toner detection sensor for each color in the process unit for each color. It is possible to appropriately determine whether there is a full error in the copy.

  In this printer as well, the transfer rate prediction value may be stored instead of storing the remaining rate prediction values (K2, K4) of the normally charged toner and the reversely charged toner in the ROM 105. The predicted transfer rate is a predicted transfer rate of toner from the photoconductor to the intermediate transfer belt 61. If the transfer rate prediction value is subtracted from 100 [%], the residual rate prediction value is obtained. Therefore, the residual rate prediction value may be obtained by such calculation.

Next, an example in which a more characteristic configuration is added to the printer according to the second embodiment will be described. Unless otherwise specified, the configuration of the printer according to the example is the same as that of the second embodiment.
[Third embodiment]
In the printer according to the third embodiment, similarly to the printer according to the first embodiment, as the cumulative operating time of the developing device increases, the residual rate prediction values (K2, K4) of the normally charged toner and the reversely charged toner Is gradually increased.

  Here, the characteristic part of the third embodiment will be described based on the processing flow of the waste toner accumulation amount calculation process executed by the main control unit 100 shown in FIG. This processing flow is performed individually for each color process unit. When the main control unit 100 starts the calculation process, the main control unit 100 first waits for the progress of the flow until the end of the single-sheet print job (step 1: hereinafter, step is denoted as S), and then stored in the memory tag. The cumulative surface moving distance D of the photoconductor is updated (S2). Next, the normal charge toner residual rate prediction value K2 and the reverse charge toner residual rate prediction value K4 corresponding to the cumulative surface moving distance D are specified from the data table in the ROM 105 (S3). Then, after calculating the developing toner amount Mg1 per print based on the number of output dots, etc. (S4), multiplication with the normal charge toner residual rate prediction value K2 results in the transfer of the normal charge toner per sheet remaining. After calculating the amount M1 (S6), the transfer remaining amount cumulative value Mrb of the normally charged toner is updated by adding the calculation results (S7).

  After the transfer remaining amount accumulated value Mrb is updated in this way, the above-mentioned total number of dots obtained by multiplying the surface movement distance D1 of the photosensitive member by the number of dots per unit distance required per print is described above. The number of dots in the non-image portion is calculated by subtracting the number of output dots per print calculated from the writing data. Then, by multiplying the number of dots in the non-image area by the one-dot toner adhesion amount predicted value K5 of the reversely charged toner, the amount of oppositely charged toner Mx per print is calculated (S8). Then, by multiplying the calculation result Mx by the reverse charge toner residual ratio prediction value K4, the transfer remaining amount M2 of the reverse charge toner per print is obtained (S9). Further, the transfer remaining amount cumulative value Mrc of the reversely charged toner is updated by adding the transfer remaining amount M2 (S10).

  Finally, the waste toner accumulation amount Mra is calculated by adding the transfer remaining amount accumulated value Mrb of the normally charged toner and the transfer remaining amount accumulated value Mrc of the reversely charged toner (S11), and the calculation result is stored in the third RAM 104 or the memory tag. Write (S12).

  Instead of the residual rate prediction values K2 and K4, the transfer rate prediction values of the regular charged toner and the reversely charged toner may be used, and a process of decreasing the cumulative surface moving distance may be executed. .

[Fourth embodiment]
Similar to the second embodiment, a humidity sensor is provided, and the detection result is output to the main control unit 100. As the humidity increases, the remaining rate prediction values of the normally charged toner and the reversely charged toner (K2, K4) You may make it raise gradually. Accordingly, it is possible to reduce inappropriateness of the detection timing of the full error due to the fluctuation of humidity, and more accurately predict the arrival timing of the full error of the waste toner.

  FIG. 8 is a flowchart showing a processing flow of a calculation process of the accumulated amount of waste toner performed by the main control unit 100. This processing flow is also performed individually for each color process unit. When starting the calculation process, the main control unit 100 first waits for the progress of the flow until one print job is completed (S1), and then acquires the humidity detection result from the humidity sensor (S2). Next, the remaining rate prediction value K2 of the normally charged toner corresponding to the humidity and the remaining rate prediction value K4 of the reversely charged toner are specified from the data table in the ROM 105 (S3). Thereafter, the waste toner cumulative amount Mra is calculated in the same manner as the flow after S4 in FIG.

  As described above, in the first and second embodiments, the example in which the developing toner amount is calculated based on the predicted developing toner amount with respect to one dot of the latent image has been described. For the purpose of calculating accurately, the toner consumption amount of the overlapping portion may be calculated separately from the dot center portion with reference to the dot arrangement.

  Further, the developing toner amount may be calculated based on the area of the latent image instead of the number of pixels of the latent image (number of dots). Further, the reversely charged toner adhesion amount may be calculated based on the area of the background portion instead of the number of pixels (dot number) of the background portion.

  Moreover, although the example which employ | adopted what has one CPU and several RAM as the main control part 100 as a calculation means was demonstrated, multiple CPUs or only one data storage means, such as RAM, are provided. You may not. Further, the data storage means is not limited to RAM or ROM, but may be a hard disk or flash memory.

  Further, a so-called tandem printer in which a plurality of photoconductors 3Y, 3M, 3C, and 3K are provided to form a full color image has been described. However, the present invention can be applied to a single full color or monochrome image forming apparatus. Applicable. In the single full color system, only one latent image carrier such as a photoconductor is provided, and a plurality of developing devices are opposed to the latent image carrier, and Y, M, and C are sequentially formed by one latent image carrier. , K toner images are superimposed on an intermediate transfer member to obtain a full color image.

  As described above, in the printer according to the first embodiment, at least the number of dots, which is the number of pixels of the electrostatic latent image calculated based on the image information, and the normally charged toner coefficient (development toner amount prediction value and residual rate prediction value). ) Based on at least the surface movement distance of the photosensitive member as the latent image carrier and the inversely charged toner coefficient (predicted toner adhesion amount and predicted residual rate). Thus, the main control unit 100, which is a calculation means, is configured to calculate the reversely charged toner transfer remaining amount. In such a configuration, while the remaining amount of the normally charged toner transfer is calculated by a method similar to the conventional method, the remaining amount of the reversely charged toner transfer can be calculated based on a readily obtainable parameter such as the surface movement distance of the photoreceptor. it can.

  In the printer according to the first embodiment, at least the development toner amount predicted value per pixel (1 dot) of the latent image and the residual charge predicted value of the normally charged toner are used as the normally charged toner coefficient. In addition, the main control unit 100 is configured to use, as the reversely charged toner coefficient, at least a predicted toner adhesion amount of the reversely charged toner per unit surface movement distance of the photosensitive member and a predicted remaining rate of the reversely charged toner. is doing. In such a configuration, it is possible to accurately obtain the remaining transfer amount of the normally charged toner and the reversely charged toner based on those coefficients.

  In the printer according to the second embodiment, at least the number of dots, which is the number of pixels of the electrostatic latent image calculated based on the image information, and the regular charged toner coefficient (development toner amount prediction value and residual rate prediction value). ) Based on the image information, and at least the number of dots in the non-image area calculated based on the image information and the inversely charged toner coefficient (predicted toner adhesion amount and residual rate). The main control unit 100, which is a calculation means, is configured to calculate the reversely charged toner transfer remaining amount based on the predicted value. In such a configuration, the remaining charge amount of the normally charged toner is calculated by a method similar to the conventional method, and the remaining charge amount of the reversely charged toner can be calculated in consideration of the number of dots of the non-image portion to which the reversely charged toner adheres. it can. For this reason, the remaining transfer amount of the reversely charged toner can be calculated accurately regardless of the image pattern having various image areas, and the accumulated amount of waste toner can be determined more accurately.

  In the printer according to the second embodiment, the number of pixels in the non-image portion is the total number of pixels while the photoconductor is rotating and the number of pixels of the latent image calculated based on the image information. The main control unit 100 serving as calculation means is configured to calculate based on the above. In such a configuration, the number of pixels in the non-image portion can be calculated based on a parameter that can be easily acquired, such as the cumulative total number of pixels and the number of pixels in the latent image. Specifically, the main control unit 100 is configured so as to calculate by subtracting the number of pixels of the latent image from the cumulative total number of pixels, and the number of pixels in the non-image part can be calculated by simple calculation. .

  In the printer according to the second embodiment, at least the development toner amount predicted value per pixel (1 dot) of the latent image and the residual rate predicted value of the normally charged toner are used as the normally charged toner coefficient. In addition, the main control unit 100 is configured to use at least a predicted toner adhesion amount of the reversely charged toner per pixel of the non-image portion and a predicted remaining rate of the reversely charged toner as the reversely charged toner coefficient. Yes. In such a configuration, it is possible to accurately obtain the remaining transfer amount of the normally charged toner and the reversely charged toner based on those coefficients.

  Further, in the printers according to the first and second embodiments, the main control unit 100 is configured so as to use a value that is higher than the predicted value of the remaining rate of the normally charged toner as the predicted value of the remaining rate of the reversely charged toner. It is composed. In such a configuration, it is possible to accurately determine the remaining transfer amount of the reversely charged toner in accordance with the actual situation that the reversely charged toner is more likely to remain on the photosensitive member at the transfer nip than the regular charged toner.

  In the printers according to the first and second embodiments, a humidity sensor is provided, and the detection result is output to the main control unit 100. As the humidity increases, the remaining regular charged toner or reversely charged toner remains. The rate prediction values (K2, K4) may be gradually increased. Accordingly, it is possible to reduce inappropriateness of the detection timing of the full error due to the fluctuation of humidity, and more accurately predict the arrival timing of the full error of the waste toner.

  In the printers according to the first and second embodiments, the charging device 5, the developing device 10, the drum cleaning device 20, the waste toner storage unit 22, and the like disposed around the photosensitive member 3 have a common casing ( It is held by a holding body) and is detachably attached to the printer main body. Thereby, maintainability can be improved.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 3 is an enlarged configuration diagram illustrating a process unit for K in the printer. The expansion perspective view which shows the process unit. FIG. 2 is a block diagram showing a part of an electric circuit of the printer. 3 is a flowchart illustrating a processing flow performed by a main control unit of the printer according to the first embodiment. 9 is a flowchart illustrating a processing flow performed by a main control unit of a printer according to a second embodiment. 10 is a flowchart illustrating a processing flow performed by a main control unit of a printer according to a third embodiment. 10 is a flowchart illustrating a processing flow performed by a main control unit of a printer according to a fourth embodiment.

Explanation of symbols

3Y, M, C, K: photoconductor (latent image carrier)
10K: Developing device (developing means)
20K: Drum cleaning device 21K: Cleaning blade (removal means)
22K: Waste toner container (waste toner container)
50: Optical writing unit (latent image writing means)
60: Transfer unit (transfer means)
100: Main control unit (calculation means)

Claims (16)

A latent image carrier that carries a latent image on its surface; latent image writing means for writing a latent image on the surface based on image information; and a toner attached to the latent image on the surface to form the latent image A developing means for developing, a transferring means for transferring the toner image obtained on the surface by the development to a transfer body, and the toner image remaining on the surface after passing through a transfer step by the transferring means based on the image information. An image forming apparatus comprising: a calculating unit that calculates the amount of toner that is present;
At least based on the image information and a normal charge toner coefficient that is a coefficient related to a normal charge toner charged to a normal polarity, a normal charge toner transfer remaining amount that is a transfer remaining amount of the normal charge toner is calculated, and Based on at least a reversely charged toner coefficient that is a coefficient related to a reversely charged toner charged to a polarity opposite to the normal polarity, a reversely charged toner transfer remaining amount that is a transfer remaining amount of the reversely charged toner is calculated, and the normally charged toner The calculating means is configured to calculate the addition result of the transfer remaining amount and the reversely charged toner transfer remaining amount as the amount of toner remaining on the surface of the latent image carrier after passing through the transfer step. An image forming apparatus. The image forming apparatus according to claim 1.
At least the normal charge toner transfer remaining amount is calculated based on the number or area of pixels of the latent image calculated based on the image information and the normal charge toner coefficient, and at least the latent image carrier An image forming apparatus, wherein the calculation unit is configured to calculate the reversely charged toner transfer remaining amount based on a surface moving distance and the reversely charged toner coefficient. The image forming apparatus according to claim 1 or 2,
As the normal charge toner coefficient, at least a development toner amount prediction value per pixel of the latent image and a transfer rate prediction value or a residual ratio prediction value of the normal charge toner are used, and as the reverse charge toner coefficient, at least, The calculating means is configured to use the toner adhesion amount predicted value of the reversely charged toner per unit surface moving distance of the latent image carrier and the transfer rate predicted value or residual rate predicted value of the reversely charged toner. An image forming apparatus. The image forming apparatus according to claim 1.
The calculation means is configured to calculate the reverse charge toner transfer remaining amount of the non-image portion of the latent image carrier based on the image information and the coefficient relating to the reverse charge toner as the reverse charge toner transfer remaining amount. An image forming apparatus characterized by comprising. The image forming apparatus according to claim 4.
At least the normal charge toner transfer remaining amount is calculated based on the number or area of pixels of the latent image calculated based on the image information and the normal charge toner coefficient, and at least based on the image information. An image forming apparatus comprising: the calculating unit configured to calculate the reversely charged toner transfer remaining amount based on the calculated number of pixels or area of the non-image portion and the reversely charged toner coefficient. The image forming apparatus according to claim 4 or 5,
The number of pixels of the non-image part is calculated based on the cumulative total number of pixels while the latent image carrier is rotating and the number of pixels of the latent image calculated based on the image information. Further, the area of the non-image part is calculated as described above so as to be calculated based on the accumulated total area during rotation of the latent image carrier and the area of the latent image calculated based on the image information. An image forming apparatus comprising a means. The image forming apparatus according to claim 4, 5 or 6.
The number of pixels of the non-image portion is calculated by subtracting the number of pixels of the latent image from the cumulative total number of pixels while the latent image carrier is rotating, and the area of the non-image portion is An image forming apparatus comprising the calculating means configured to subtract the area of the latent image from the accumulated total area while the latent image carrier is rotating. The image forming apparatus according to any one of claims 4, 5, 6, and 7.
As the normal charge toner coefficient, at least a development toner amount prediction value per pixel of the latent image and a transfer rate prediction value or a residual ratio prediction value of the normal charge toner are used, and as the reverse charge toner coefficient, at least, The calculation means is configured to use the toner adhesion amount predicted value of the reversely charged toner per pixel of the non-image portion of the latent image carrier and the transfer rate predicted value or the residual rate predicted value of the reversely charged toner. An image forming apparatus. The image forming apparatus according to claim 3 or 8,
The reversely charged toner transfer rate predicted value is lower than the normally charged toner transfer rate predicted value, or the reversely charged toner residual rate predicted value is used as the reversely charged toner residual rate predicted value. An image forming apparatus characterized in that the calculating means is configured to use a value higher than a predicted value. The image forming apparatus according to claim 3, 8 or 9,
Predicted development toner amount value, transfer rate prediction value of normally charged toner, predicted remaining rate of normally charged toner, predicted toner adhesion amount, predicted transfer rate of reversely charged toner, and remaining rate of reversely charged toner An image forming apparatus, wherein the calculation unit is configured to change at least one of the predicted values over time. The image forming apparatus according to claim 10.
As the cumulative operating time of the developing means increases, the above calculation is performed so that the predicted transfer rate of the reversely charged toner is lowered or the predicted value of the remaining rate of the reversely charged toner is increased. An image forming apparatus comprising a means. The image forming apparatus according to claim 10 or 11,
As the cumulative operating time of the developing means increases, the above-mentioned calculation is performed so that the transfer rate prediction value of the normally charged toner is lowered or the remaining rate prediction value of the normally charged toner is increased. An image forming apparatus comprising a means. The image forming apparatus according to any one of claims 3, 8, 9, 10, 11, or 12.
Environment detection means for detecting at least one of temperature and humidity is provided, the development toner amount prediction value, the normally charged toner transfer rate prediction value, the normally charged toner residual rate prediction value, the toner adhesion amount prediction value, The calculation unit is configured to change at least one of the predicted transfer rate of the reversely charged toner and the predicted remaining rate of the reversely charged toner based on a detection result by the environment detection unit. An image forming apparatus. The image forming apparatus according to claim 13.
As the temperature or humidity detection result rises, the calculation is performed so that the predicted transfer rate of the reversely charged toner is lowered or the predicted remaining rate of the reversely charged toner is increased. An image forming apparatus comprising a means. The image forming apparatus according to claim 13 or 14,
As the detection result of the temperature or humidity rises, the above calculation is performed so that the predicted transfer rate of the normally charged toner is lowered or the predicted remaining rate of the normally charged toner is increased. An image forming apparatus comprising a means. The image forming apparatus according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15.
A removal unit that removes transfer residual toner remaining on the surface of the latent image carrier after passing through a transfer step by the transfer unit, and a waste that stores the transfer residual toner removed by the removal unit as waste toner. The waste toner storage means is provided on a common holding body together with at least one of the latent image carrier and the developing means so as to be integrated with the image forming apparatus main body. An image forming apparatus characterized by being detachable.

Images