JP4556529B2 - Toner amount adjusting apparatus and method, toner amount adjusting program - Google Patents

Description

  The present invention relates to a toner amount adjusting device and method, and a toner amount adjusting program, and in particular, forms a toner image on an image carrier using toner contained in a developing device, and transfers the formed toner image to an intermediate transfer member. The present invention relates to a toner amount adjusting apparatus and method for adjusting a toner amount in a developing device in an image forming apparatus that forms an image by transferring the image to a recording medium through a recording medium, and a toner amount adjusting program.

  Conventionally, various types of image forming apparatuses such as copying machines and printers to which an electrophotographic system is applied have been proposed and have already been commercialized. Among the image forming apparatuses described above, color image forming apparatuses that form full-color images can be roughly divided into a type using an intermediate transfer member and a type not using an intermediate transfer member. The image forming apparatus using the intermediate transfer member temporarily transfers the toner image formed on the photosensitive member onto the intermediate transfer member, so that the primary transfer can be performed regardless of the material of the recording medium. It has the feature that it is advantageous for high image quality.

  As the color image forming apparatus using the intermediate transfer member, there are a so-called “4-cycle method” and a so-called “tandem method”. A “4-cycle” color image forming apparatus is a primary image in which toner images of each color such as yellow, magenta, cyan, and black, which are sequentially formed on a single photoconductor, are superimposed on each other on an intermediate transfer body. After the transfer, a toner image of yellow, magenta, cyan, black, etc. transferred in multiple layers onto the intermediate transfer member is secondarily transferred onto a recording medium by a secondary transfer roll so as to form a color image. It is configured.

  Conventionally, in view of the fact that the density of the reference patch mark and the toner amount of each color in the developing device have a correlation, a reference patch mark for each color is formed on the intermediate transfer member, and the density of the reference patch mark is increased. By detecting toner, the amount of stored toner is stabilized by replenishing or discharging toner to each color developing device in the developing device (see Patent Document 1 or Patent Document 2). . Hereinafter, this toner amount adjustment by supplying or discharging the toner amount is referred to as “TC density adjustment control”.

  In the TC density adjustment control, a reference patch mark is formed when a series of jobs are completed. Conventionally, as in the case of actual image formation, reference patch marks are formed in the order of Y color → M color → C color → K color, and each reference patch mark is provided along the movement locus of the intermediate transfer member. The concentration is detected by a concentration sensor (ADC sensor).

Then, the detected density value, as shown in FIG. 1 5, with a preset threshold value (predetermined width [Delta] K, i.e. have a threshold KU and lower threshold KD upper) Compare. For example, when the value exceeds the upper limit threshold KU as in the detection value KX, it is determined that the density is high and the amount of toner stored in the developer exceeds a predetermined upper limit, and is stored in the developer. The operation of discharging the toner that has been discharged is executed. Further, when the value falls below the lower limit threshold KD as in the detection value KY, it is determined that the density is low and the amount of toner stored in the developing device is below the predetermined lower limit value, and the toner is stored in the developing device. An operation of replenishing toner from the cartridge is executed.

Here, the threshold values KU and KD to be compared with the detected density value are fixed values.
Japanese Patent Laid-Open No. 3-98064 Japanese Patent No. 2565882

  However, the roughness of the intermediate transfer belt surface decreases as usage proceeds. When the roughness of the surface of the intermediate transfer belt is reduced, as shown in FIG. 16, even if a proper amount of toner is stored in the developing device and a reference patch image having a predetermined density is appropriately created, the density of the reference patch image is detected. The value decreases as the number of processed sheets increases. When the predetermined number of sheets is processed, the roughness of the intermediate transfer belt surface becomes constant, and the detected density value of the reference patch image becomes constant.

  Therefore, even if an appropriate amount of toner is stored in the developing device and a reference patch image having a predetermined density is appropriately generated, the detected value of the density of the reference patch image falls below the lower limit value KD. That is, if the number of processed sheets L or more is processed, the detected value falls below the lower limit value KD, and although it is not necessary to replenish toner, it is wasteful. Therefore, the toner amount cannot be adjusted appropriately.

  The present invention has been made in view of the above-described facts, and even when the number of times that a toner image has been transferred to the intermediate transfer member has increased, a toner amount adjusting device capable of adjusting the toner amount appropriately, and It is an object to provide a method and a toner amount adjustment program.

In order to achieve the above object, the toner amount adjusting device according to the first aspect of the present invention forms a toner image on an image carrier using toner contained in a developing device, and transfers the formed toner image to an intermediate transfer. Instructing means for instructing the intermediate transfer body to create a predetermined density image to an image forming apparatus that forms an image by transferring it to a recording medium through a body, and density detecting means for detecting the density of the predetermined density image And a comparing means for comparing the density value detected by the density detecting means with a range of density values to be detected in a predetermined density image created when the toner amount in the developing device is within a predetermined range. If, based on the result of the comparison by the comparing means, wherein the toner amount adjusting means for adjusting the amount of toner in the developing device, a toner amount adjusting apparatus wherein the density value used by said comparing means The range is a range in which the density value is moved in a lower direction as the number of times that the toner image is transferred to the intermediate transfer body is increased, and is constant in all ranges where the number of times is a predetermined value or more. It is characterized by .

  That is, the toner amount adjusting device of the present invention adjusts the toner amount in the developing device in the image forming apparatus.

  Here, the image forming apparatus forms a toner image on an image carrier using toner contained in a developing device, and transfers the formed toner image to a recording medium via an intermediate transfer member. Form an image.

  The instructing unit instructs the image forming apparatus to create a predetermined density image on the intermediate transfer member. Thereby, a predetermined density image is created on the intermediate transfer member.

  By the way, if the toner amount in the developing device is within a predetermined appropriate range, the detected value of the density of the predetermined density image is also within the predetermined appropriate range. However, when the amount of toner in the developing device exceeds the upper limit value of the appropriate range, the detected value of the density of the predetermined density image also exceeds the upper limit value of the predetermined appropriate range. When the value falls below the lower limit value of the range, the detected density value of the predetermined density image also falls below the lower limit value of the predetermined aptitude range. In this way, whether or not the toner amount in the developing device is within the predetermined appropriate range can be determined based on whether or not the detected density value of the predetermined density image is within the predetermined appropriate range. Since the detected value exceeds the upper limit value of the predetermined aptitude range or falls below the lower limit value, it can be determined that the toner amount in the developing device exceeds the upper limit value of the aptitude range or falls below the lower limit value of the predetermined aptitude range. It can be seen that the quantity should be dispensed or replenished.

  Therefore, in the toner amount adjusting apparatus of the present invention, the density detecting unit detects the density of the predetermined density image created on the intermediate transfer member, and the comparing unit detects the density value detected by the density detecting unit, and The toner amount adjustment means compares the density value range to be detected of the predetermined density image created when the toner amount in the developing device is within the predetermined range, and the toner amount adjustment means determines the result of the comparison by the comparison means. Based on this, the toner amount in the developing device is adjusted. The toner amount adjusting means controls the toner supplying means for supplying toner to the developing device, the toner discharging means for discharging the toner by developing the toner on the image carrier, and the toner supplying means or the toner discharging means. You may make it comprise by the control means to do.

  However, as described above, when the density value range used by the comparison unit is fixed, the roughness of the intermediate transfer belt surface decreases as the use proceeds, and even if the amount of toner in the developing device is appropriate, a predetermined amount is obtained. The detected density value of the density image decreases.

  Therefore, in the present invention, the range of the density value used by the comparison unit is a range in which the density value is moved in the lower direction as the number of times the toner image is transferred to the intermediate transfer member increases.

  Accordingly, the roughness of the intermediate transfer belt surface is reduced as the use proceeds, and even if the detected value of the density of the predetermined density image is reduced although the toner amount in the developing device is appropriate, it is compared with this. Since the density value range is shifted in the direction where the density value is low, it is possible to reduce the determination that the toner amount in the developing device is not appropriate even if the toner amount is appropriate. Therefore, unnecessary toner replenishment can be reduced.

  As described above, in order to adjust the toner amount, the density value range to be detected of the predetermined density image, which is compared with the density detection value of the predetermined density image, is expressed as the number of times the toner image is transferred to the intermediate transfer member. As the density increases, the density value is moved in the lower direction. Even if the use of the intermediate transfer belt is advanced, it is possible to reduce unnecessary toner replenishment and adjust the toner amount appropriately. can do.

  Specifically, storage means for storing a relationship in which the density value to be detected of the predetermined density image decreases as the number of times the toner image is transferred to the intermediate transfer body increases, and toner on the intermediate transfer body The stored predetermined density image corresponding to the number of times based on the counting means for counting the number of times the image has been transferred, the number of times counted by the counting means, and the relationship stored by the storage means. Determining means for determining a density value range corresponding to the density value to be detected, and the comparing means may use the density value range determined by the determining means.

  In this case, the storage means includes the number of times that the toner image has been transferred to the intermediate transfer member, and a range of density values to be detected in a predetermined density image that is moved in a direction in which the density value decreases as the number of times increases. , And the determination means may determine the density value range corresponding to the number of times by searching the storage means.

  In this case, the storage means includes the number of times that the toner image has been transferred to the intermediate transfer member, and the range of density values to be detected in a predetermined density image that is moved in a lower direction as the number of times increases. And a data table or a map for storing them correspondingly.

  The storage means stores a density value to be detected of the predetermined density image that decreases as the number of times the toner image is transferred to the intermediate transfer member, and the determination means uses the counting means. The density value range may be determined based on the density value to be detected in the stored predetermined density image corresponding to the counted number of times.

  In this case, the storage means stores the relational expression of the density value to be detected of the predetermined density image, which is reduced as the number of times the toner image is transferred to the intermediate transfer body, or is stored as a map. Or you may.

  By the way, as described above, when the amount of toner in the developing device is appropriate, the detected value of the density of the predetermined density image becomes constant when the number of times that the toner image is transferred to the intermediate transfer member becomes a predetermined value or more.

Therefore, the range of the density value used by the comparison unit is constant in all ranges where the number of times the toner image is transferred to the intermediate transfer member is equal to or greater than a predetermined value.

  The image forming apparatus described above is capable of forming a single color image or a plurality of color images.

  Here, when the image forming apparatus can form an image of a plurality of colors, that is, the image forming apparatus includes a plurality of developing devices that store toners of a plurality of colors, and superimposes the toner images for the respective colors via the intermediate transfer member. When an image is formed by transferring to a recording medium, the instruction unit instructs the image forming apparatus to create the predetermined density image for each color.

  The density detection unit detects the density of the predetermined density image created for each color, and the comparison unit performs the comparison for each predetermined density image created for each color, and adjusts the toner amount. The means adjusts the toner amount for each of the plurality of developing devices based on the comparison result.

  In this case, the range of the density value that is used in the comparison unit and is moved in the direction in which the density value is lowered as the number of times that the toner image is transferred to the intermediate transfer member is increased.

According to a sixth aspect of the present invention, there is provided a toner amount adjusting device comprising: an image carrier; a charger that uniformly charges the image carrier; a charging bias voltage applying unit that applies a bias voltage to the charger; and the image carrier. A latent image forming means for irradiating a body with a light beam corresponding to image data to form an electrostatic latent image; a developing device for developing the electrostatic latent image using a two-component developer containing at least toner; An image forming engine configured to apply a bias voltage to the developing device; and a primary transfer unit that primarily transfers an image formed on the image carrier by the image forming engine to an intermediate transfer member. A toner amount adjusting device for adjusting a toner amount in a developing device in an image forming apparatus comprising: a secondary transfer unit that secondarily transfers an image primarily transferred to the intermediate transfer body to a recording medium; Above An instruction unit that instructs the image forming apparatus to create a predetermined density image on the intermediate transfer member, a density detection unit that detects the density of the predetermined density image, a density value detected by the density detection unit, and the developing device A comparison unit for comparing a density value range to be detected of a predetermined density image created when the toner amount in the predetermined range is within a predetermined range, and the development based on the comparison result by the comparison unit A toner amount adjusting unit that adjusts the toner amount in the apparatus, and the density value range used by the comparing unit is such that the density value increases as the number of times the toner image is transferred to the intermediate transfer member increases. It is a range that is moved in a lower direction, and the number of times is constant in all ranges that are equal to or greater than a predetermined value .

  That is, the toner amount adjusting device of the present invention is a toner amount adjusting device that adjusts the toner amount in the developing device in the image forming apparatus.

  The image forming apparatus includes: an image engine; a primary transfer unit that primarily transfers an image formed on the image carrier by the image forming engine to an intermediate transfer member; and an image that is primarily transferred to the intermediate transfer member. Secondary transfer means for performing secondary transfer to the camera.

  The image engine corresponds to image data on the image carrier, a charger for uniformly charging the image carrier, charging bias voltage applying means for applying a bias voltage to the charger, and image data on the image carrier. A latent image forming means for irradiating a light beam to form an electrostatic latent image, a developing device for developing the electrostatic latent image using a two-component developer containing at least toner, and a bias voltage applied to the developing device. And a developing bias voltage applying means to be applied.

  The instruction means of the toner amount adjusting device of the present invention instructs the image forming apparatus to create a predetermined density image on the intermediate transfer member.

  The density detection means detects the density of the predetermined density image. The comparison unit compares the density value detected by the density detection unit with a range of density values to be detected in the predetermined density image created when the toner amount in the developing device is within the predetermined range. . The toner amount adjusting unit adjusts the toner amount in the developing device based on the comparison result by the comparing unit.

In the present invention, the density value range used by the comparison unit is a range in which the density value is moved in a lower direction as the number of times the toner image is transferred to the intermediate transfer member increases . The number of times is constant in the entire range of a predetermined value or more .

  As described above, in order to adjust the toner amount, the density value range to be detected of the predetermined density image, which is compared with the density detection value of the predetermined density image, is expressed as the number of times the toner image is transferred to the intermediate transfer member. As the density increases, the density value is moved in the lower direction. Even if the use of the intermediate transfer belt is advanced, it is possible to reduce unnecessary toner replenishment and adjust the toner amount appropriately. can do.

  Specifically, storage means for storing a relationship in which the density value to be detected of the predetermined density image decreases as the number of times the toner image is transferred to the intermediate transfer body increases, and toner on the intermediate transfer body The stored predetermined density image corresponding to the number of times based on the counting means for counting the number of times the image has been transferred, the number of times counted by the counting means, and the relationship stored by the storage means. Determining means for determining a density value range corresponding to the density value to be detected, and the comparing means may use the density value range determined by the determining means.

  In this case, the storage means includes the number of times that the toner image has been transferred to the intermediate transfer member, and a range of density values to be detected in a predetermined density image that is moved in a direction in which the density value decreases as the number of times increases. , And the determination means may determine the density value range corresponding to the number of times by searching the storage means.

  In this case, the storage means includes the number of times that the toner image has been transferred to the intermediate transfer member, and the range of density values to be detected in a predetermined density image that is moved in a lower direction as the number of times increases. And a data table or a map for storing them correspondingly.

  The storage means stores a density value to be detected of the predetermined density image that decreases as the number of times the toner image is transferred to the intermediate transfer member, and the determination means uses the counting means. The density value range may be determined based on the density value to be detected in the stored predetermined density image corresponding to the counted number of times.

  In this case, the storage means stores the relational expression of the density value to be detected of the predetermined density image, which is reduced as the number of times the toner image is transferred to the intermediate transfer body, or is stored as a map. Or you may.

  By the way, as described above, when the amount of toner in the developing device is appropriate, the detected value of the density of the predetermined density image becomes constant when the number of times that the toner image is transferred to the intermediate transfer member becomes a predetermined value or more.

Therefore, the range of the density value used by the comparison unit is constant in all ranges where the number of times the toner image is transferred to the intermediate transfer member is equal to or greater than a predetermined value.

  The image forming apparatus described above is capable of forming a single color image or a plurality of color images.

  Here, when the image forming apparatus can form an image of a plurality of colors, that is, the image forming engine has, for each of a plurality of colors, the developing device, the developing bias voltage applying unit, the toner replenishing unit, and In the case where the toner discharge unit is provided and a toner image is formed for each color, and the primary transfer unit superimposes the toner image formed for each color by the image forming engine on the intermediate transfer member, the instruction unit includes: The image forming apparatus is instructed to create the predetermined density image for each color.

  The density detection unit detects the density of the predetermined density image created for each color, and the comparison unit performs the comparison for each predetermined density image created for each color, and adjusts the toner amount. The means adjusts the toner amount for each of the plurality of developing devices based on the comparison result.

  In this case, the range of the density value that is used in the comparison unit and is moved in the direction in which the density value is lowered as the number of times that the toner image is transferred to the intermediate transfer member is increased.

According to a ninth aspect of the present invention, there is provided a toner amount adjusting method in which a toner image is formed on an image carrier using toner contained in a developing device, and the formed toner image is transferred to a recording medium via an intermediate transfer member. Thus, an image forming apparatus for forming an image creates a predetermined density image on the intermediate transfer member, detects the density of the predetermined density image, and the detected density value and the amount of toner in the developing device are A toner amount adjusting device that compares a density value range to be detected of a predetermined density image created when it is within a predetermined range and adjusts the toner amount in the developing device based on the comparison result a is the range of the density values used during said comparison, the following toner image on the intermediate transfer member is the number of times that has been transferred, with a range in which the density value is moved to a lower direction, the Number of times is a predetermined value In all the above ranges, it is constant .

Toner amount adjustment program of the invention of claim 1 0, wherein the toner image formed on an image bearing member using the toner contained in the developing device, the formed toner image, to the recording medium via an intermediate transfer member By transferring, an image forming apparatus that forms an image creates a predetermined density image on the intermediate transfer member, detects the density of the predetermined density image, detects the detected density value, and the amount of toner in the developing device A toner amount that compares the density value range to be detected of the predetermined density image created when the toner is within the predetermined range and adjusts the toner amount in the developing device based on the comparison result A toner amount adjustment processing program for causing a computer to execute adjustment processing, wherein the density value range used in the comparison is increased as the number of times a toner image is transferred to the intermediate transfer member increases. Further, the density value is moved in a lower direction, and the number of times is constant in all ranges greater than or equal to a predetermined value .

Incidentally, the action of the invention of claim 9, 1 0, wherein the effect is similar to the first aspect of the present invention and description thereof will be omitted.

  As described above, according to the present invention, in order to adjust the toner amount, the density value range to be detected of the predetermined density image, which is compared with the density detection value of the predetermined density image, is stored in the intermediate transfer member. As the number of times the toner image is transferred increases, the density value is moved in the lower direction. Therefore, even if the use of the intermediate transfer belt surface is advanced, it is possible to reduce unnecessary toner replenishment. The toner amount can be adjusted appropriately.

  Hereinafter, a toner amount adjusting apparatus and method, and a toner amount adjusting program according to an embodiment of the present invention will be described in detail with reference to the drawings.

(overall structure)
FIG. 1 shows a main body of a full-color printer 1, and an engine unit 1A as an image forming engine is disposed inside the full-color printer main body 1.

  A photosensitive drum 2 as an image carrier is rotatably disposed at an upper right part slightly from the center of the engine part 1A. As this photosensitive drum 2, for example, a drum made of a conductive cylinder having a diameter of about 47 mm whose surface is coated with a photosensitive layer made of OPC or the like is used. It is rotationally driven at a process speed of about 150 mm / sec. As shown in FIG. 1, the surface of the photosensitive drum 2 is charged to a predetermined potential by a charging roll 3 as a charger disposed almost immediately below the photosensitive drum 2. Image exposure by a laser beam (LB) is performed by a ROS (Raster Output Scanner) 4 serving as an exposure unit disposed at a position immediately below 2 to form an electrostatic latent image corresponding to image information. The electrostatic latent image formed on the photosensitive drum 2 passes through the developing devices 5Y, 5M, 5C, and 5K of yellow (Y), magenta (M), cyan (C), and black (K) in the circumferential direction. The toner is developed by a rotary developing device 5 arranged along the toner image to be a toner image of a predetermined color.

  At this time, charging, exposure and development processes are repeated a predetermined number of times on the surface of the photosensitive drum 2 in accordance with the color of the image to be formed. The rotary developing device 5 is rotationally driven at a predetermined timing, and the developing devices 5Y, 5M, 5C, and 5K corresponding to the color to be developed move to a developing position facing the photosensitive drum 2.

  For example, when a full-color image is formed, the charging, exposure, and development processes are performed on the surface of the photosensitive drum 2 in yellow (Y), magenta (M), cyan (C), and black (K) colors. The toner image corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) is sequentially formed on the surface of the photosensitive drum 2. . The number of rotations of the photosensitive drum 2 when the toner image is formed varies depending on the size of the image. For example, in the case of an A4 size, the photosensitive drum 2 is rotated three times so that one color image is obtained. Is formed.

  That is, each time the photosensitive drum 2 rotates three times, toner images corresponding to yellow (Y), magenta (M), cyan (C), and black (K) colors are sequentially formed on the surface of the photosensitive drum 2. It is formed. As will be described later, the toner images sequentially formed on the photosensitive drum 2 are primarily transferred in a state of being superimposed on the intermediate transfer belt 6 when passing through the primary transfer position.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images sequentially formed on the photosensitive drum 2 are arranged on the outer periphery of the photosensitive drum 2 as intermediate transfer bodies. At the primary transfer position around which the transfer belt 6 is wound, the primary transfer is performed by the primary transfer roll 7 while being superimposed on the intermediate transfer belt 6. The yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred in multiple onto the intermediate transfer belt 6 are fed by the secondary transfer roll 8 at a predetermined timing. The recording sheet 9 is secondarily transferred in a lump. The secondary transfer roll 8 may be configured to follow the intermediate transfer belt 6, but may be configured to be rotationally driven via a gear from a driving source (not shown).

  At this time, the secondary transfer roll 8 rotates idly when the rotational speed of the secondary transfer roll 8 becomes faster so that there is no difference in moving speed with the intermediate transfer belt 6. In addition, it is desirable to be configured to be driven to rotate through a torque limiter.

  As shown in FIG. 1, the recording paper 9 is fed by a pickup roll 11 from a paper feeding unit 10 arranged at the lower part of the full-color printer main body 1 and is rolled one by one by a feed roll 12 and a retard roll 13. In this state, the sheet is fed to the secondary transfer position of the intermediate transfer belt 6 in synchronization with the toner image transferred onto the intermediate transfer belt 6 by the registration roll 14. The secondary transfer roll 8 is configured to contact and separate from the surface of the intermediate transfer belt 6 at a predetermined timing. The secondary transfer roll 8 as the load unit is disposed at a position where the distance on the circumference of the intermediate transfer belt 6 is close to the downstream side of the photosensitive drum, and the load unit is the intermediate transfer belt as will be described later. 6 is configured to reduce or increase the driving speed of the photosensitive member in response to the timing of contact with the photosensitive member 6.

  As shown in FIG. 1, the intermediate transfer belt 6 is stretched by a plurality of rolls, and rotates along with the rotation of the photosensitive drum 2 so as to circulate at a predetermined process speed (about 150 mm / sec). It is configured to be driven. As the intermediate transfer belt 6, a belt made of an elastic belt having elasticity such as chloroprene, urethane rubber, silicon rubber or the like whose Young's modulus of the elastic layer is 30 MPa or less is used.

  The intermediate transfer belt 6 also includes a wrap-in roll 15 that specifies the wrap position of the intermediate transfer belt 6 on the upstream side in the rotation direction of the photosensitive drum 2 and a toner image formed on the photosensitive drum 2. A primary transfer roll 7 to be transferred onto the intermediate transfer belt 6, a wrap-out roll 16 for specifying the wrap position of the intermediate transfer belt 6 on the downstream side of the wrap position, and the secondary transfer roll 8 via the intermediate transfer belt 6. It is stretched at a predetermined tension by a backup roll 17 that abuts, a first cleaning backup roll 19 that faces the cleaning device 18 of the intermediate transfer belt 6, and a second cleaning backup roll 20.

  Further, as described above, the intermediate transfer belt 6 is stretched by a plurality of rolls 7, 15-17, 19, and 20. In this embodiment, in order to reduce the size of the full-color printer body 1, The stretched cross-sectional shape is configured to be a flat and elongated substantially trapezoidal shape.

  Furthermore, in this embodiment, as shown in FIG. 1, the entire full color printer is miniaturized as much as possible, but the rotary developing device 5 occupies a large space of the full color printer main body 1. Therefore, the full-color printer main body 1 is designed to improve the maintainability of the intermediate transfer belt 6 and the rotary developing device 5 while achieving downsizing of the device. Specifically, the intermediate transfer belt 6 includes the photosensitive drum 2, the charging roll 3, and the secondary transfer roll 8, and integrally constitutes an image forming unit 21, and the upper cover 22 of the full-color printer main body 1. By opening, the entire image forming unit 21 is configured to be detachable from the full-color printer main body 1. Further, on the upper portion of the intermediate transfer belt 6, a density sensor 23 composed of a reflection type photosensor for detecting the density of a reference patch image of toner formed on the intermediate transfer belt 6 is disposed.

  Further, as shown in FIG. 1, the cleaning device 18 for the intermediate transfer belt 6 includes a scraper 24 disposed so as to abut on the surface of the intermediate transfer belt 6 stretched by a first cleaning backup roll 19; And a cleaning brush 25 disposed so as to be in pressure contact with the surface of the intermediate transfer belt 6 stretched by the second cleaning backup roll 20. Residual toner and paper dust removed by removing means such as the scraper 24 and the cleaning brush 25 are collected in the cleaning device 18. The cleaning device 18 is supported so as to be able to swing counterclockwise around the swing shaft 26, and is retracted to a position away from the surface of the intermediate transfer belt 6. It is configured to contact the surface of the intermediate transfer belt 6 at a predetermined timing.

  Further, the recording paper 9 onto which the toner image is transferred from the intermediate transfer belt 6 is conveyed to a fixing device 27 as shown in FIG. 1, and the toner image is transferred onto the recording paper 9 by heat and pressure by the fixing device 27. In the case of single-sided printing, the paper is discharged as it is onto a discharge tray 29 provided at the top of the printer body 1 by a discharge roll 28.

  On the other hand, in the case of double-sided printing, the recording paper 9 on which the toner image is fixed by the fixing device 27 is not discharged as it is onto the discharge tray 29 by the discharge roll 28, but the rear end portion of the recording paper 9 by the discharge roll 28. In a state where the discharge roll 28 is reversed, the conveyance path of the recording paper 9 is switched to the double-sided paper conveyance path 30, and the conveyance roll 31 disposed in the double-sided paper conveyance path 30 With the recording paper 9 turned upside down, the recording paper 9 is conveyed again to the secondary transfer position of the intermediate transfer belt 6 to form an image on the back surface of the recording paper 9.

  Furthermore, as shown in FIG. 1, a manual feed tray 32 can be attached to the side surface of the printer main body 1 so as to be freely opened and closed in the full color printer. An arbitrary size and type of recording paper 9 placed on the manual feed tray 32 is fed by a paper feed roll 33, and a secondary transfer position of the intermediate transfer belt 6 via a transport roll 31 and a registration roll 14. As a result, the image can be formed on the recording paper 9 of any size and type.

  The surface of the photosensitive drum 2 after the toner image transfer process is completed is cleaned by a cleaning blade 35 of a cleaning device 34 disposed obliquely below the photosensitive drum 2 every time the photosensitive drum 2 rotates once. As a result, residual toner and the like are removed to prepare for the next image forming process.

  In the full-color printer according to the present embodiment, the photosensitive drum 2 is rotated at a predetermined peripheral speed (about 150 mm / sec) directly or via a plurality of gears or the like by a drive source (not shown) such as a stepping motor. It is configured to be driven. Further, the intermediate transfer belt 6 is configured to be driven and rotated by the photosensitive drum 2 while being wound around the surface of the photosensitive drum 2.

  Further, as shown in FIG. 2, a rectangular reference position mark 41 for detecting the rotation period of the intermediate transfer belt 6 is synthesized on the surface of the intermediate transfer belt 6 at one end portion in the width direction. It is provided so as to reflect light by fusion of resin and aluminum.

  The reference position mark 41 is a reference position detecting means (a light emitting element or a light receiving element) composed of a reflective optical sensor or the like disposed near the lower surface of the intermediate transfer belt 6 along the circulation path of the intermediate transfer belt 6. (Configuration) 42 is detected.

  Further, the secondary transfer roll 8 is configured to come in contact with and separate from the surface of the intermediate transfer belt 6 at a predetermined timing. Further, the cleaning device 18 is configured to come into contact with and separate from the surface of the intermediate transfer belt 6 at a predetermined timing.

(Developing device 5)
As shown in FIG. 3, the developing device 5 includes a developing device main body 40 that is rotatably arranged in a vertical plane. The developing device main body 40 includes a cylindrical rotating shaft member 41 disposed along the longitudinal direction at the center thereof, and a front side disposed at an end portion on the near side in the longitudinal direction of the rotating shaft member 41. Formed by a flange member 42, a rear flange member 43 disposed at the end in the longitudinal direction of the rotary shaft member 41, and the rotary shaft member 41 and front and rear flange members 42, 43. And a partition member 44 that divides the cylindrical space S into four sections every 90 °.

  The developing device main body 40 is attached to the engine unit 1A so as to be rotatable along the counterclockwise direction as shown in FIG.

  As shown in FIG. 4, the developing device main body 40 includes four developer cartridges 45Y and 45M of yellow (Y), magenta (M), cyan (C), and black (K) along the clockwise direction. 45C and 45K are mounted along the circumferential direction.

  Since these developing units 5Y, 5M, 5C, and 5K are all configured in the same manner, here, the yellow (Y) developing unit 5Y will be described as an example. 5, a developing device main body 46 is provided, and a new developer is supplied to the developing device main body 46 from a corresponding developer cartridge 45Y.

  As shown in FIG. 5, the developing device main body 46 is disposed so that a part thereof is exposed in an opening 47 provided facing the outer periphery of the developing device main body 46, and in a direction perpendicular to the paper surface. A long developing roll 48 and two spiral augers 49 and 50 that are positioned obliquely below the developing roll 48 and extend in parallel with the developing roll 48 are disposed.

  In the developing unit 5Y, when the developing roll 48 rotates, the spiral auger 49 on the back side conveys the developer 51 accommodated in the developing unit main body 46 while stirring in one direction perpendicular to the paper surface.

  On the other hand, the spiral auger 50 conveys the developer 51 while stirring the developer 51 in the direction opposite to the conveying direction of the spiral auger 49 and supplies the developer 51 evenly to the developing roll 48.

  In this embodiment, a two-component developer composed of a toner and a carrier is used as the developer 51. However, the developer 51 only needs to contain at least toner, and is composed only of toner. Component developers may be used.

  The developing roll 48 adsorbs a carrier contained in the developer 51 with a magnetic force by a magnet roll 48a disposed in a fixed state inside, and forms a magnetic brush of the developer 51 on the surface of the developing roll 48, thereby providing a carrier. The toner adsorbed on the toner is conveyed to a developing area facing the photosensitive drum 2. The electrostatic latent image formed on the photosensitive drum 2 is visualized by the toner formed on the surface of the developing roll 48.

(Image formation control system)
FIG. 6 is a block diagram of a control system for image formation in the engine unit 1A.

  The main power management unit 100 is connected to a commercial power source (not shown), generates a low voltage power source and a high voltage power source, and supplies power to each unit via a power supply line.

  A user interface 104 is connected to the main controller 102, and an instruction regarding image formation or the like is given by a user's operation, and information on the image formation or the like is notified to the user. A memory 103 is connected to the main controller 102. The memory 103 stores a reference map for calculating a threshold value, as will be described later.

  The main controller 102 is connected to a network line with an external host computer (not shown) so that image data is input.

  When the image data is input, the main controller 102, for example, analyzes the print instruction information included in the image data and the image data, and converts them into a format (for example, bitmap data) suitable for the engine unit 1A. Image data is sent to the image formation processing control unit 106.

  The image forming process control unit 106 controls each of the optical scanning system control unit 108, the drive system control unit 110, the charger control unit 112, the developing device control unit 114, and the fixing device control unit 116 based on the input image data. Synchronous control is performed to execute image formation.

  The drive system control unit 110 is connected to the density sensor 23 and the reference position detection means 42. The density detected by the density sensor 23 and the reference position detected by the reference position detection means 42 are controlled by the image forming process control. Also output to the main controller 102 via the unit 106.

  For example, the density sensor 23, the developing device main body 40, the main controller 102, the developing device control unit 114, and the like constitute a toner amount adjusting device.

  The operation of this embodiment will be described below.

(Normal print operation)
In the full color printer according to the present embodiment, a color image printing operation is performed as follows.

  In the full-color printer, the photosensitive drum 2 is driven to rotate at a predetermined speed (about 150 mm / sec) during the printing operation, and the intermediate transfer belt 6 is driven while being wound around the surface of the photosensitive drum 2. .

  Thereafter, the surface of the photosensitive drum 2 is charged to a predetermined potential by the charging roll 3 and then subjected to image exposure corresponding to the first yellow image by the ROS 4 to form an electrostatic latent image. The The electrostatic latent image formed on the photosensitive drum 2 is developed by the yellow developing device 5Y of the rotary developing device 5, and a yellow toner image is formed on the surface of the photosensitive drum 2. .

  At this time, the surface of the intermediate transfer belt 6 has been in contact with the cleaning device 18 before the first yellow image exposure is performed on the surface of the photosensitive drum 2. The surface of the intermediate transfer belt 6 is cleaned by a cleaning device 18. That is, in the first yellow image exposure on the surface of the photosensitive drum 2, the cleaning device 18 remains in contact with the surface of the intermediate transfer belt 6 that is wound around the surface of the photosensitive drum 2 and driven. It is performed in the state.

  When the yellow image exposure on the surface of the photosensitive drum 2 is completed, the cleaning device 18 is separated from the surface of the intermediate transfer belt 6. At this time, the yellow toner image formed on the surface of the photosensitive drum 2 is in a state of being primarily transferred onto the intermediate transfer belt 6 at the primary transfer position.

  Thereafter, the surface of the photosensitive drum 2 is charged to a predetermined potential by the charging roll 3 and then subjected to image exposure corresponding to, for example, a second magenta image by the ROS 4 to form an electrostatic latent image. The The electrostatic latent image formed on the photosensitive drum 2 is developed by a magenta developer 5M of the rotary developing device 5, and a magenta toner image is formed on the surface of the photosensitive drum. The magenta toner image formed on the surface of the photosensitive drum 2 is primarily transferred in a superimposed state on the intermediate transfer belt 6 on which the yellow toner image has already been transferred at the primary transfer position.

  Next, the surface of the photosensitive drum 2 is charged to a predetermined potential by the charging roll 3 and then subjected to image exposure corresponding to the third cyan image by the ROS 4 to form an electrostatic latent image. The The electrostatic latent image formed on the photosensitive drum 2 is developed by a cyan developing device 5C of the rotary developing device 5, and a cyan toner image is formed on the surface of the photosensitive drum 2. . The cyan toner image formed on the surface of the photosensitive drum 2 is primarily transferred in a state of being superimposed on the intermediate transfer belt 6 on which the yellow and magenta toner images have already been transferred at the primary transfer position. Is done.

  Further, the surface of the photosensitive drum 2 is charged to a predetermined potential by the charging roll 3 and then subjected to image exposure corresponding to the black image of the fourth color by the ROS 4 to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 2 is developed by the black developing device 5K of the rotary developing device 5, and a black toner image is formed on the surface of the photosensitive drum 2. As shown in FIG. 1, the black toner image formed on the surface of the photosensitive drum 2 is transferred onto the intermediate transfer belt on which the yellow, magenta, and cyan toner images have already been transferred at the primary transfer position. The primary transfer is performed in a superposed state.

  At this time, the secondary transfer roll 8 contacts the surface of the intermediate transfer belt 6 prior to the black image exposure.

  When the black image exposure on the photosensitive drum 2 is completed, the cleaning device 18 comes into contact with the surface of the intermediate transfer belt 6.

  Thus, the secondary transfer roll 8 has been in contact with the surface of the intermediate transfer belt 6 before the surface of the photosensitive drum 2 is exposed to the black image of the final color. In other words, the black image exposure of the final color on the surface of the photosensitive drum 2 is performed while the secondary transfer roll 8 is in contact with the surface of the intermediate transfer belt 6 that is wound around the surface of the photosensitive drum 2 and driven. It is performed in the state.

  When the secondary transfer roll 8 comes into contact with the intermediate transfer belt 6, the image on which the four colors are superimposed is transferred onto the recording paper 9, fixed by passing through the fixing device 27, and discharged.

Thereafter, residual toner, paper dust, and the like on the intermediate transfer belt 6 are removed by a removing unit such as a scraper 24 and a cleaning brush 25, and are collected inside the cleaning device 18.
(TC concentration adjustment)
Next, a toner amount adjustment method and a toner amount adjustment program will be described.

  When printing is completed as described above, step 150 of the toner amount adjustment program shown in FIG. 7 is determined to be affirmative, and in step 200, TC density adjustment control of the K toner is performed.

  Here, when printing is completed as described above, the toner image finally superimposed on the intermediate transfer member is a black toner image, and corresponds to the photosensitive drum 2 as shown in FIG. The black developing device 5K is located at the position. In this state, in step 200, as shown in FIG. 10B, TC density adjustment control of the K color toner in the developing device 5K is performed. For example, for TC density adjustment control of the Y color toner, There is no need to wait until the developing device rotates, such as when the developing device 5Y reaches a position corresponding to the photosensitive drum 2, and the normal printing can be quickly shifted to the toner amount adjustment.

  Next, details of step 200 will be described with reference to FIG. In step 202 in FIG. 8, the number of processed sheets is calculated. That is, the number of A4-sized images formed in the printing process is calculated. If the print is an A4 size image, it can be calculated as it is, that is, counted up. However, when the print is an image other than A4 size, it is calculated by converting to the area of A4. For example, if the print is an A3 size image that is twice the A4 size, the calculation is made assuming that two A4 images have been processed. It is assumed that the calculated number of processed sheets is i.

  In step 204, the image formation processing control unit 106 is instructed to create a K-color reference patch image (predetermined density image), thereby creating a reference patch image PGK.

  In step 206, the density K of the K reference patch image PGK is detected. It should be noted that the density of the reference patch image PGK may be detected once, or the average value of a plurality of densities may be obtained by detecting the density at a plurality of locations in the reference patch image PGK.

  In addition, when calculating | requiring an average value, you may make it calculate | require the average value of each density | concentration of detection values other than the maximum value and minimum value among the density | concentration values of the reference | standard patch image PGK.

  As described above, when the average value is obtained using the density values at a plurality of positions of the reference patch image PGK, the influence can be suppressed even if the irregular reflection states of light on the intermediate transfer belt and the reference patch image are different.

  Further, as described above, since the average value is obtained using the density of the reference patch image PGK at each of the detected value positions other than the maximum value and the minimum value, the influence of the irregular reflection state of light can be further suppressed.

  In the next step 208, a threshold value corresponding to the processed number i is calculated. The memory 103 stores a map (see FIG. 9) that serves as a reference for calculating the threshold value.

  That is, as described above, the roughness of the intermediate transfer belt surface decreases as the use proceeds. When the roughness of the surface of the intermediate transfer belt is reduced, as shown in FIG. 9, even if a proper amount of toner is stored in the developing device 5K and the reference patch image is appropriately created, the detected value of the density of the reference patch image is As the number of processed sheets increases, when the predetermined number of sheets (for example, 3000 sheets) is processed, the roughness of the intermediate transfer belt surface becomes constant, and the detected density value of the reference patch image becomes constant.

  Therefore, in the memory 300, an appropriate amount of toner is stored in the developing device 5K, and when the reference patch image is appropriately generated, the number of processed images decreases as the number of processed images increases, and a predetermined number (for example, 3000) A map indicating the relationship between the density value of the reference patch image that becomes constant when processed is stored.

  In step 208, first, the density value of the reference patch image corresponding to the processed number i is determined from the map. That is, for example, assuming that the processed sheet number i = p, the density value KP of the reference patch image corresponding to the processed sheet number i = p is determined from the map. Then, an upper limit value KUP (= KP + (ΔK / 2)) of the density range is calculated by adding a value (ΔK / 2) that is 1/2 the density range ΔK to the determined density value KP. At the same time, the density value lower limit value KDP (= KP− (ΔK / 2)) is subtracted from the determined density value KP by a value (ΔK / 2) that is 1/2 the density range ΔK. Calculate

  In step 210, it is determined whether or not the density K of the K reference patch image PGK is larger than the upper limit value KUP. If the density K of the K-color reference patch image PGK is larger than the upper limit value KUP (K> KUP), it is determined that the density is high, and an operation of discharging the toner stored in the developing device 5K is executed.

  If the density K of the K reference patch image PGK is smaller than the lower limit value KDP (K <KDP), it is determined that the density is low, and the toner stored in the developing device 5K is replenished with toner from the toner cartridge. Perform the action to be performed.

  When the above processing ends, the K color TC density adjustment control in step 200 in FIG. 7 ends. In the next step 300, Y color TC density adjustment control is performed. In this case, first, the developing device 5 is rotated by a predetermined angle (90 degrees). For example, at the time of K color TC density adjustment control, as shown in FIG. 10A, the K color developing device 5K is positioned at a position corresponding to the photosensitive drum 2, so that the Y color TC density adjustment control is performed. For this purpose, the developing device 5 is rotated by a predetermined angle (90 degrees) so that the Y-color developing device 5K is positioned at a position corresponding to the photosensitive drum 2.

  Thereafter, the above steps 202 to 214 are executed. Since these steps 210 to 270 are the same as the processing at the time of K color TC density adjustment control, the description thereof is omitted. However, a map serving as a threshold value reference in the Y color TC density adjustment control is obtained and stored in advance for the Y color.

  Note that the TC density adjustment control for the M color and the C color in subsequent steps 400 and 500 is substantially the same as in step 300 described above, and thus the description thereof is omitted. However, maps in the TC density adjustment control for each of the M color and the C color are also obtained and stored in advance for the M color and the C color.

  Further, in the C color TC density adjustment control in step 500, after the toner supply or discharge is completed, the development position is set to the home position. Note that the home position is, for example, a position where the Y-color developing device 5Y corresponds to the photosensitive drum 2 in consideration of the next printing and the formation of a Y-color toner image (see FIG. 10C). ).

  As described above, in order to adjust the toner amount, the density value range to be detected of the predetermined density image compared with the density detection value of the predetermined density image is set to the number of processed sheets (the toner image is transferred to the intermediate transfer belt). The density value is moved in the lower direction as the number of times increases), and even if the use of the intermediate transfer belt surface is advanced, the amount of wasted toner can be reduced and the toner amount can be reduced. Can be adjusted appropriately.

  By the way, in the present embodiment, when the TC density adjustment control for the K color to the TC density adjustment control for the C color are executed in order, as shown in FIG. 11, the Y color to the C color after the K reference patch image PGK. The reference patch images PGY to PGC are sequentially formed from the position Pk of the reference patch image PGK on the downstream side in the transport direction F of the intermediate transfer belt 6 at distances Ly, Lm, and Lc.

  The reason why this is done will be described with reference to FIGS. The reference patch image PGK is removed by the tip of the scraper 24. However, when the reference patch image PGK is not completely removed, the remaining area of the reference patch image PGK is considered to be an area M1 shown in FIG. That is, the remaining area of the reference patch image PGK is a predetermined area on the upstream side in the conveyance direction of the intermediate transfer belt 6. When the reference patch image PGY is formed in this area M1 and the density thereof is detected, the density of the reference patch PGK before remaining is reflected in the detected density value of the reference patch image PGY. Therefore, the toner amount cannot be adjusted with high accuracy.

  Therefore, the reference patch image PGY is formed in an area other than the remaining area M1 of the reference patch image PGK, that is, on the downstream side in the transport direction of the intermediate transfer belt 6 from the reference patch image PGK as shown in FIG. To do.

  In the same manner, the reference patch image PGM is transferred from the reference patch image PGY to the intermediate transfer belt as shown in FIG. 12C except for the remaining area M2 (and M1) of the reference patch image PGY. The reference patch image PGC is formed downstream of the remaining area M3 (and M1, M2) of the reference patch image PGM, that is, as shown in FIG. The intermediate transfer belt 6 is formed downstream of the PGM in the conveyance direction.

  As described above, in the present embodiment, when the reference patch images are generated in order for each of a plurality of colors, the already created reference patch images are completely scraped off with respect to the generation positions of the second and subsequent color reference patch images. Since it is created outside the expected remaining region of the reference patch image, which is expected when it is not possible, it is possible to prevent the density of other remaining reference patch images from being reflected in the detected density value of the reference patch. .

  In the above-described example, FIGS. 12B to 12D and FIGS. 12D and 12D are assumed to be outside the expected remaining area of the reference patch image, which is expected when the already created reference patch image is not scraped completely. As shown in FIG. 13A, the reference patch image that has already been created is on the downstream side in the intermediate transfer belt conveyance direction, but the present invention is not limited to this, as shown in FIG. 13B. In addition, the area adjacent to the expected remaining area M of the reference patch image may be used. In this case, the already created reference patch image may be downstream or upstream of the intermediate transfer belt conveyance direction.

  In the embodiment described above, when the appropriate amount of toner is stored in the reference developing device in the memory and the reference patch image is appropriately generated, the number of processed images decreases as the number of processed images increases, and the predetermined number A map indicating the relationship between the density value of the reference patch image that becomes constant when processed is stored.

  However, the present invention is not limited to this. For example, as shown in FIG. 14, when an appropriate amount of toner is stored in the reference developing device and a reference patch image is appropriately generated, the number of processed sheets decreases as the number of processed sheets increases and a predetermined number of sheets are processed. You may make it memorize | store the map which shows the relationship between the upper limit and lower limit calculated | required as mentioned above based on the density | concentration value of the reference | standard patch image which becomes fixed.

  Instead of the map, a relational expression indicating the relationship (relation between the number of processed sheets and the density value of the reference patch image, the relationship between the number of processed sheets and the upper limit value and the lower limit value) may be stored.

  Further, it may be stored as a data table instead of the map and the relational expression.

1 is a configuration diagram illustrating a main part of a full-color printer according to an embodiment. FIG. 3 is a development view of an intermediate transfer belt. It is a perspective view of a developing device. FIG. 3 is a cross-sectional view perpendicular to the axis of the developing device. FIG. 6 is an enlarged cross-sectional view illustrating details of a developing unit taking Y color as an example. It is a block diagram of the control system for image formation in an engine part. It is a flowchart which shows a TC density | concentration control program. It is a flowchart which shows the detailed flow of step 200 of FIG. It is a graph which shows the relationship between the number of processed sheets memorize | stored in memory, and a density value. FIGS. 8A to 8C are diagrams illustrating a moving state of the developing device when shifting to TC density control from the end of printing. It is a figure which shows the arrangement position of the reference | standard patch image of K color-C color. (A)-(D) is a figure which shows the flow of preparation of the reference | standard patch image of K color-C color. It is a figure which shows the modification of the arrangement position of a reference | standard patch image. It is another graph which shows the relationship between the number of processed sheets memorize | stored in memory, and a density value. It is a figure which shows the threshold value in the conventional TC density | concentration control. FIG. 6 is a diagram illustrating that the detected value of the density of a toner image decreases with the number of processed sheets, regardless of the toner amount being appropriate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Full color printer 1A Engine part 2 Photosensitive drum (image carrier)
3 Charging roll (charger)
4 ROS (image forming means)
5 Developing Device 6 Intermediate Transfer Belt 7 Primary Transfer Roll 8 Secondary Transfer Roll 9 Recording Paper (Recording Medium)
18 Cleaning device 23 Concentration sensor (concentration detection means)
24 Scraper (removal means)
25 Cleaning brush (removal means)
27 Fixing device 40 Developing device main body (toner supply means, toner discharge means)
42 Reference position detecting means 48 Developing roll 49 Spiral auger 50 Spiral auger 51 Developer 102 Main controller (indicating means)
103 memory (storage means)
DESCRIPTION OF SYMBOLS 104 User interface 106 Image formation process control part 108 Optical scanning system control part 110 Drive system control part 112 Charger control part (charging bias voltage application means)
114 Developing device control unit (developing bias voltage applying means, toner amount adjusting means)
116 Fixing unit control unit 124 Process control unit PGK K color reference patch image PGY Y color reference patch image PGM M color reference patch image PGC C color reference patch image

Claims (10)

An image forming apparatus for forming an image by forming a toner image on an image carrier using toner contained in a developing device, and transferring the formed toner image to a recording medium via an intermediate transfer member. Instruction means for instructing the intermediate transfer member to create a predetermined density image;
Density detecting means for detecting the density of the predetermined density image;
A comparison unit that compares the density value detected by the density detection unit with a range of density values to be detected in a predetermined density image created when the toner amount in the developing device is within a predetermined range;
A toner amount adjusting means for adjusting a toner amount in the developing device based on a result of the comparison by the comparing means;
A toner amount adjusting device comprising:
The range of the density value used by the comparison means is a range in which the density value is moved in a lower direction as the number of times that the toner image is transferred to the intermediate transfer member increases, and the number of times is equal to or greater than a predetermined value. Is constant over the entire range of
And a toner amount adjusting device. Storage means for storing a relationship in which the density value to be detected of the predetermined density image decreases as the number of times the toner image is transferred to the intermediate transfer body increases;
Counting means for counting the number of times the toner image has been transferred to the intermediate transfer member;
Based on the number of times counted by the counting means and the relationship stored by the storage means, the density value corresponding to the density value to be detected of the stored predetermined density image corresponding to the number of times A determination means for determining a range;
With
The comparing means uses a range of density values determined by the determining means;
The toner amount adjusting apparatus according to claim 1, wherein The storage means corresponds to the number of times that the toner image has been transferred to the intermediate transfer body and the range of density values to be detected in a predetermined density image that is moved in a direction in which the density value decreases as the number of times increases. And remember
The determination means determines the density value range corresponding to the number of times by searching the storage means.
The toner amount adjusting device according to claim 2, wherein The storage means stores a density value to be detected of the predetermined density image, which decreases as the number of times the toner image is transferred to the intermediate transfer body increases.
The determining unit determines a range of the density value based on a density value to be detected of the stored predetermined density image corresponding to the number of times counted by the counting unit;
The toner amount adjusting device according to claim 2, wherein An image carrier, a charger for uniformly charging the image carrier, charging bias voltage applying means for applying a bias voltage to the charger, and irradiating the image carrier with a light beam corresponding to image data. Latent image forming means for forming an electrostatic latent image, a developing device for developing the electrostatic latent image using a two-component developer containing at least toner, and a developing bias voltage application for applying a bias voltage to the developing device An image forming engine comprising:
Primary transfer means for primarily transferring an image formed on the image carrier by the image forming engine to an intermediate transfer member;
Secondary transfer means for secondary transfer of the image primarily transferred to the intermediate transfer member to a recording medium;
A toner amount adjusting device for adjusting a toner amount in a developing device in an image forming apparatus comprising:
Instruction means for instructing the image forming apparatus to create a predetermined density image on the intermediate transfer member;
Density detecting means for detecting the density of the predetermined density image;
A comparison unit that compares the density value detected by the density detection unit with a range of density values to be detected in a predetermined density image created when the toner amount in the developing device is within a predetermined range;
A toner amount adjusting means for adjusting a toner amount in the developing device based on a result of the comparison by the comparing means;
With
The range of the density value used by the comparison means is a range in which the density value is moved in a lower direction as the number of times that the toner image is transferred to the intermediate transfer member increases, and the number of times is equal to or greater than a predetermined value. Is constant over the entire range of
And a toner amount adjusting device. Storage means for storing a relationship in which the density value to be detected of the predetermined density image decreases as the number of times the toner image is transferred to the intermediate transfer body increases;
Counting means for counting the number of times the toner image has been transferred to the intermediate transfer member;
Based on the number of times counted by the counting means and the relationship stored by the storage means, the density value corresponding to the density value to be detected of the stored predetermined density image corresponding to the number of times A determination means for determining a range;
With
The comparing means uses a range of density values determined by the determining means;
The toner amount adjusting apparatus according to claim 5, wherein The storage means corresponds to the number of times that the toner image has been transferred to the intermediate transfer body and the range of density values to be detected in a predetermined density image that is moved in a direction in which the density value decreases as the number of times increases. And remember
The determination means determines the density value range corresponding to the number of times by searching the storage means.
The toner amount adjusting device according to claim 6. The storage means stores a density value to be detected of the predetermined density image, which decreases as the number of times the toner image is transferred to the intermediate transfer body increases.
The determining unit determines a range of the density value based on a density value to be detected of the stored predetermined density image corresponding to the number of times counted by the counting unit;
The toner amount adjusting device according to claim 6. An image forming apparatus that forms an image by forming a toner image on an image carrier using toner contained in a developing device, and transferring the formed toner image to a recording medium via an intermediate transfer body, Create a predetermined density image on the intermediate transfer member,
Detecting the density of the predetermined density image;
Comparing the detected density value with a range of density values to be detected in a predetermined density image created when the amount of toner in the developing device is within a predetermined range;
Adjusting the amount of toner in the developing device based on the result of the comparison;
A toner amount adjusting method,
The range of the density value used in the comparison is a range in which the density value is moved in a lower direction as the number of times that the toner image is transferred to the intermediate transfer member increases, and the number of times is a predetermined value. Constant in all of the above ranges,
And a toner amount adjusting method. An image forming apparatus that forms an image by forming a toner image on an image carrier using toner contained in a developing device, and transferring the formed toner image to a recording medium via an intermediate transfer body, Create a predetermined density image on the intermediate transfer member,
Detecting the density of the predetermined density image;
Comparing the detected density value with a range of density values to be detected in a predetermined density image created when the amount of toner in the developing device is within a predetermined range;
Adjusting the amount of toner in the developing device based on the result of the comparison;
A toner amount adjustment processing program for causing a computer to execute toner amount adjustment processing,
The range of the density value used in the comparison is a range in which the density value is moved in a lower direction as the number of times that the toner image is transferred to the intermediate transfer member increases, and the number of times is a predetermined value. Constant in all of the above ranges,
A toner amount adjustment program.

Images