JP4973694B2 - Image forming apparatus and image adjusting method - Google Patents

Description

  The present invention relates to an image forming apparatus used for electrophotographic image formation applicable to, for example, a copying machine, a facsimile machine, a printer, or a multi-function machine thereof, and an image adjustment method in the image forming apparatus.

  In an electrophotographic image forming apparatus, a developing method employed for developing an electrostatic latent image formed on an image carrier includes a one-component developing method using only toner as a main component of a developer, and a developing method. A two-component development method using a toner and a carrier as main components of the agent, and a so-called hybrid development method intended to enjoy the advantages of both by combining the one-component development method and the two-component development method. It has been known.

In the two-component development system, development is performed by supplying only the toner to the latent image on the image carrier directly from the developer carrier carrying the developer composed of toner and carrier without going through the toner carrier. Done.
On the other hand, in the hybrid development method, only the toner is supplied to the toner carrier from the developer carrier that carries the developer composed of toner and carrier, and the latent image on the image carrier is developed by the one-component development method. Done. It is known that the so-called image memory (image history) problem is more prominent in this hybrid development method than in the one-component development method and the two-component development method.

  In the one-component development method, a supply roller that is composed of a sponge or the like and has a toner recovery function is in contact with the toner carrier, and the toner on the toner carrier is accurately adjusted by the contact pressure between the sponge and the toner carrier surface. It can be recovered well. In the two-component development system, generally, a part of the developer carrying member is disposed so as to come into contact with the developer in the developing tank, and toner is supplied and recovered in the process of passing therethrough.

  On the other hand, in the case of the hybrid development method, the toner on the toner carrier must be collected by the rising of the carrier on the developer carrier, and sufficient recoverability can be secured stably. In general, it is considered difficult to generate a memory image due to a difficult relationship. As a method for improving the toner recoverability in this hybrid developing system, it is conceivable to provide a separate member for toner recovery. However, this increases the cost of the apparatus and increases the size of the apparatus, and promotes the deterioration of the developer. There is a problem that.

  In connection with such a problem, for example, Patent Document 1 discloses a process for substantially predicting the effect of reloading error on a test patch after development, and compensating for the effect of predicted reloading error on the test patch. According to the process of adjusting the digital data associated with the test patch, the process of generating a developed test patch based on the adjusted digital data, the process of detecting the developed test patch, and the detection data from the test patch And a process for adjusting the toner output.

JP 2004-354996 A

However, the conventional toner control method basically compensates for the previous printing history appearing in the toner layer on the toner carrier with the latent image on the electrostatic latent image carrier without directly eliminating this. is there.
Therefore, in this case, it is necessary to grasp in advance the developing property of the toner from the toner carrier to the electrostatic latent image carrier. However, the toner from the toner carrier to the electrostatic latent image carrier is required. Since there are many factors related to the developability of the toner, such as the durability history of the toner, the durability history of the electrostatic latent image carrier, and the environment, it is difficult to cope with a single table.

  Therefore, a table is prepared in advance for each of the factors such as the durability history of the toner, the durability history of the electrostatic latent image carrier, and the environment, and the table is selected by detecting these factors. Although it is conceivable, the correction accuracy decreases as the number of related factors increases. In addition, when the table is created from the test patch, there is a problem that the test patch and the calculation amount become enormous and the correction time becomes very long.

  As described above, when considering the correspondence between the durability history of the toner, the durability history of the electrostatic latent image carrier, and the environment, etc., using a previously created table, there are too many factors to be considered in the correction. However, there is a problem that it is difficult to correct accurately and an image memory may be generated even when there is no previous print history on the toner carrier.

By the way, it has been found that when the image memory caused mainly by the previous printing history on the toner carrier is to be eliminated, the following problems may occur as a side effect.
For example, when a so-called “solid image” is obtained by performing printing with a coverage area ratio of 100% (that is, full-surface printing), the density of the rear end portion of the image is lowered depending on conditions, and the solid followability is deteriorated. In some cases, problems may occur.

  That is, the memory image is not necessarily generated even if the toner on the toner carrier is not completely recovered. Under such conditions, the solid density development of the toner on the toner carrier is performed around the toner carrier. When the amount is larger than the amount of toner supplied from the developer carrier to the toner carrier, the amount of toner on the toner carrier decreases every time the toner carrier rotates, and when the toner carrier makes one turn, the developer Saturates with the amount supplied from the carrier to the toner carrier. At this time, if the required density cannot be secured by the amount of toner supplied from the developer carrier to the toner carrier, the density of the rear end portion of the image is lowered.

In addition, when the time for developing the toner from the toner carrier to the electrostatic latent image carrier is short, it becomes difficult for the toner to reach the electrostatic latent image carrier, resulting in poor gradation reproducibility and fine line reproducibility. In some cases, defects such as defects, graininess defects, or image density unevenness may occur.
The poor gradation reproducibility is caused by the fact that the latent image on the electrostatic latent image carrier is isolated in the so-called half portion (intermediate density portion) of the density. This is because the effective potential difference from the latent image portion of the image carrier becomes small, the toner hardly reaches the electrostatic latent image carrier, and the density is difficult to reproduce. The thin line reproducibility failure is also caused by the fact that the latent image on the electrostatic latent image carrier is isolated, as in the case of the half portion.

  Further, the poor granularity is due to the fact that the latent image on the electrostatic latent image carrier can be clearly reproduced depends on the number of reciprocations of the toner between the toner carrier and the electrostatic latent image carrier. In addition, the image density unevenness decreases as the potential difference between the toner carrier and the electrostatic latent image carrier decreases due to the flare and vibration of the toner carrier and the electrostatic latent image carrier. Is due to.

  Accordingly, the present invention provides an image forming apparatus capable of suppressing the occurrence of inconvenience that may occur when the image memory is eliminated while directly eliminating the print history on the toner carrier that causes the image memory. It was made as a basic purpose.

For this reason, the image forming apparatus according to the first invention of the present application includes: a) a developer carrying member carrying a developer containing non-magnetic toner and a magnetic carrier; and b) the developer carrying via a supply / recovery region. A toner carrier that is disposed opposite the electrostatic latent image carrier via the developing region and carries the toner supplied from the developer carrier in the supply and recovery region; c) A first electric field for supplying and collecting toner is formed between the developer carrier and the toner carrier between the developer carrier and the toner carrier, and the toner carrier The toner is transferred from the toner carrier to the latent image portion on the electrostatic latent image carrier between the body and the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. And an electric field forming means for forming an electric field of 2 An apparatus,
A detection means for detecting the image memory and the solid followability, respectively, and a control means for controlling the image memory and the solid followability, respectively, wherein the control means determines a toner carrying amount per unit area on the toner carrier. The solid-state followability is controlled by controlling the development-side peripheral speed ratio, which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier, while controlling the image memory. In addition, the control means has a control flow for adjusting the solid followability after the adjustment of the image memory.

The image forming apparatus according to the second invention of the present application includes: a) a developer carrying member that carries a developer containing a non-magnetic toner and a magnetic carrier; and b) the developer carrying member through a supply / recovery region. And a toner carrier that is disposed to face the electrostatic latent image carrier via the development region and carries the toner supplied from the developer carrier in the supply and recovery region; c) Forming a first electric field between the developer carrier and the toner carrier between the developer carrier and the toner carrier to supply and collect toner; and the toner carrier The toner is transferred from the toner carrier to the latent image portion on the electrostatic latent image carrier to make the electrostatic latent image visible as a toner image between the toner and the electrostatic latent image carrier. An image forming apparatus comprising a developing device having an electric field forming unit There is,
An image memory, solid tracking capability, and gradation reproducibility; and a control unit that controls the image memory, solid tracking capability, and gradation reproducibility, respectively. While controlling the image memory by controlling the toner carrying amount per unit area above, the developing side circumferential speed ratio, which is the ratio of the circumferential speed of the toner carrying body to the circumferential speed of the electrostatic latent image carrying body, is set. The solid state followability and gradation reproducibility are controlled by controlling, and the control means has a control flow for adjusting the solid followability and gradation reproducibility after first adjusting the image memory. It is characterized by that.

Furthermore, an image forming apparatus according to a third invention of the present application includes: a) a developer carrier that carries a developer containing non-magnetic toner and a magnetic carrier; and b) the developer carrier through a supply / recovery region. And a toner carrier that is disposed to face the electrostatic latent image carrier via the development region and carries the toner supplied from the developer carrier in the supply and recovery region; c) Forming a first electric field between the developer carrier and the toner carrier between the developer carrier and the toner carrier to supply and collect toner; and the toner carrier The toner is transferred from the toner carrier to the latent image portion on the electrostatic latent image carrier to make the electrostatic latent image visible as a toner image between the toner and the electrostatic latent image carrier. An image forming apparatus comprising a developing device having an electric field forming unit There is,
An image memory, solid tracking capability, and fine line reproducibility; and a control unit that controls the image memory, solid tracking capability, and fine line reproducibility, respectively. The image memory is controlled by controlling the amount of toner carried per unit area, while the developing-side peripheral speed ratio, which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier, is controlled. The solid followability and fine line reproducibility are thereby controlled, and the control means further includes a control flow for adjusting the solid followability and fine line reproducibility after first adjusting the image memory. It is characterized by that.

Furthermore, an image forming apparatus according to a fourth invention of the present application includes: a) a developer carrying member that carries a developer containing non-magnetic toner and a magnetic carrier; and b) the developer carrying through a supply / recovery region. A toner carrier that is disposed opposite the electrostatic latent image carrier via the developing region and carries the toner supplied from the developer carrier in the supply and recovery region; c) A first electric field for supplying and collecting toner is formed between the developer carrier and the toner carrier between the developer carrier and the toner carrier, and the toner carrier The toner is transferred from the toner carrier to the latent image portion on the electrostatic latent image carrier between the body and the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. And an electric field forming means for forming an electric field of 2 An apparatus,
An image memory, solid followability and granularity detection means; and an image memory, solid followability and granularity control means. The control means has a unit area on the toner carrier. By controlling the image memory by controlling the amount of toner carried per unit, while controlling the development-side peripheral speed ratio, which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier The solid followability and graininess are controlled, and the control means further has a control flow for adjusting the solid followability and graininess after first adjusting the image memory. It is a thing.

Furthermore, an image forming apparatus according to a fifth invention of the present application includes: a) a developer carrying member that carries a developer containing non-magnetic toner and a magnetic carrier; and b) the developer carrying via a supply / recovery region. A toner carrier that is disposed opposite the electrostatic latent image carrier via the developing region and carries the toner supplied from the developer carrier in the supply and recovery region; c) A first electric field for supplying and collecting toner is formed between the developer carrier and the toner carrier between the developer carrier and the toner carrier, and the toner carrier The toner is transferred from the toner carrier to the latent image portion on the electrostatic latent image carrier between the body and the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. And an electric field forming means for forming an electric field of 2 An apparatus,
An image memory, solid followability and image density unevenness detection means; and an image memory, solid followability and image density unevenness control means, respectively, the control means on the toner carrier. The image memory is controlled by controlling the amount of toner carried per unit area, while the developing-side peripheral speed ratio, which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier, is controlled. The solid followability and image density unevenness are thereby controlled, and the control means has a control flow for adjusting the solid followability and image density unevenness after first adjusting the image memory. It is characterized by that.

The image adjusting method in the image forming apparatus according to the sixth invention of the present application includes: a) a developer carrying member that contains a non-magnetic toner and a magnetic carrier; and b) the supply through the supply / recovery region. A toner carrier that faces the developer carrying member and is opposed to the electrostatic latent image carrier through the developing region, and carries the toner supplied from the developer carrying member in the supply and recovery region; C) forming a first electric field for supplying and collecting toner between the developer carrier and the toner carrier between the developer carrier and the toner carrier; and Between the toner carrier and the electrostatic latent image carrier, the toner is transferred from the toner carrier to the latent image portion on the electrostatic latent image carrier, and the electrostatic latent image is visualized as a toner image. And an electric field forming means for forming a second electric field to be developed. An image adjustment method in an image forming apparatus equipped with,
Detecting at least one of an image memory and solid traceability, gradation reproducibility, fine line reproducibility, graininess, and image density unevenness, respectively, and controlling a toner carrying amount per unit area on the toner carrying member After adjusting the image memory by controlling the development side peripheral speed ratio, which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier, the solid followability and gradation reproduction The image adjustment is performed for at least one of image quality, fine line reproducibility, graininess, and image density unevenness.

In the above case, the control means may control the toner carrying amount per unit area on the toner carrying body by controlling an average potential difference ΔV _avg of the supply and recovery region. The developing-side peripheral speed ratio may be controlled by controlling the rotational speed of the toner carrier.

  Further, the control means may adjust the solid followability after first adjusting the image memory after setting the number of rotations of the toner carrier to the lowest speed in the use range at the time of image adjustment. preferable. Furthermore, a plurality of toner carriers may be provided.

According to the present invention, the detection means for detecting the image memory and the solid followability (or gradation reproducibility, fine line reproducibility, graininess, and image density unevenness in addition to these), the image memory and the solid followability (or In addition to these, control means for controlling gradation reproducibility, fine line reproducibility, graininess, and image density unevenness), and the control means controls the amount of toner carried per unit area on the toner carrier. The image memory is controlled by controlling the development side peripheral speed ratio, which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier. In addition to controlling gradation reproducibility, fine line reproducibility, graininess, and image density unevenness), after image memory adjustment, solid traceability (or in addition to these, gradation reproducibility, fine line reproducibility, graininess, Dark image Since the unevenness is adjusted, the print history on the toner carrier that causes the image memory is directly eliminated, and the solid tracking failure (or in addition to this) that can occur when the image memory is eliminated is added. The occurrence of inconvenience due to poor tone reproducibility, fine line reproducibility failure, graininess failure, and image density unevenness failure can be suppressed.

It is explanatory drawing which shows the part relevant to the image formation of the electrophotographic image forming apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the example of 1 connection of an electric field formation means. It is explanatory drawing which shows the relationship between the voltage supplied to the developing agent conveyance roller and the developing roller from the electric field formation means shown in FIG. 2A. It is explanatory drawing which shows the other example of a connection of an electric field formation means. It is explanatory drawing which shows the other example of a connection of an electric field formation means. It is a figure which shows the specific example of the bias voltage by the electric field formation means which concerns on the said embodiment. It is a figure which shows the specific example of the bias voltage in a supply collection | recovery electric field. It is explanatory drawing which shows the control flow of the image adjustment which concerns on Example 1 of this invention. 10 is an explanatory diagram illustrating a control flow of image adjustment according to a comparative example 1. FIG. 6 is a graph showing a relationship between an average voltage ΔV _avg of a supply / recovery electric field and a toner conveyance amount Q on a developing roller. Is a graph showing the relationship between the average voltage [Delta] V _avg supply recovery field and a DC voltage component VSdc applied to the developing agent conveying roller. It is explanatory drawing which shows the control flow of the image adjustment which concerns on Example 2 of this invention. It is explanatory drawing which shows the control flow of the image adjustment which concerns on Example 3 of this invention. It is explanatory drawing which shows the control flow of the image adjustment which concerns on Example 4 of this invention. It is explanatory drawing which shows the control flow of the image adjustment which concerns on Example 5 of this invention. It is explanatory drawing which shows the control flow of the image adjustment which concerns on Example 6 of this invention. It is a figure which illustrates an image memory, (a) is a figure which shows an example of "without image memory", (b) is a figure which shows an example of "with image memory", respectively. It is a figure which illustrates solid followability, (a) is a figure which shows an example of "solid followability favorable", (b) is an example which respectively shows an example of "solid followability is insufficient." It is a figure which illustrates gradation reproducibility, (a) is an example which shows an example of "good gradation reproducibility", and (b) is an example which respectively shows an example of "poor gradation reproducibility". It is a figure which illustrates thin line reproducibility, (a) is a figure which shows an example of "good fine line reproducibility", (b) is an example which respectively shows an example of "thin line reproducibility defect". It is a figure which illustrates a granularity, (a) is a figure which shows an example of "good granularity", (b) is a figure which shows an example of "poor graininess", respectively. It is a figure which illustrates image density nonuniformity, (a) is an example which shows an example of "image density nonuniformity", (b) is an example which respectively shows an example of "image density nonuniformity".

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, terms indicating a specific direction (for example, “up”, “down”, “left”, “right”, and other terms including them, “clockwise direction”, “counterclockwise” ”) Is used to facilitate understanding of the invention with reference to the drawings, and the present invention should not be construed as being limited by the meaning of these terms. Further, in the image forming apparatus and the developing apparatus described below, the same reference numerals are used for the same or similar components.

[Image forming apparatus]
FIG. 1 shows a portion related to image formation of an electrophotographic image forming apparatus according to an embodiment of the present invention.
The image forming apparatus M1 according to the present embodiment performs image formation by transferring a toner image formed on an image carrier (photoconductor) 1 to a transfer medium P such as paper by an electrophotographic method. , A printer, a facsimile machine, or a multi-function machine having these functions in combination.

The image forming apparatus M1 has an image carrier 1 (so-called photoconductor) for carrying an electrostatic latent image. The image carrier 1 is connected to a motor (not shown) and is driven by the motor. Rotate in the direction of the arrow based on Around the image carrier 1, there are charging means 6 for charging the image carrier 1, exposure means 7 for exposing the image carrier 1 to form an electrostatic latent image, and the electrostatic latent image. A developing device 2 for developing the toner, a transfer means 8 for transferring the developed toner image on the image carrier 1, and a cleaning means 9 for removing residual toner on the image carrier 1. They are arranged in order along the direction (see arrow Y4).
For the image carrier 1, the charging means 6, the exposure means 7, the transfer means 8, the cleaning means 9 and the like used in the electrophotographic apparatus, a well-known electrophotographic technique can be arbitrarily used. For example, although a charging roller is shown in FIG. 1 as the charging unit 6, a charging device that is not in contact with the image carrier 1 may be used.

The developing device 2 includes a developer tank 28 that stores the developer 25 and a developer transport roller 23 that transports the developer 25 supplied from the developer tank 28 while supporting the developer 25 on the surface. A developing roller 21 that can separate the toner from the developer 25 of the roller 23 is provided.
The developer 25 in the developing tank 28 is mixed and stirred by the rotation of the mixing and stirring means 26 and is frictionally charged, and then supplied to the sleeve roller 23 s on the surface of the developer transport roller 23. The developer 25 is held on the surface side of the sleeve roller 23s by the magnetic force of the magnet roller 23m inside the developer transport roller 23, and rotates together with the sleeve roller 23s. Then, the passage amount is regulated by a regulating member 24 provided facing the developer conveying roller 23, and then sent to a portion facing the developing roller 21.

An electric field that electrically separates and carries the toner in the developer on the surface of the developing roller 21 is formed by the first electric field forming unit 4 at the opposite portion between the developer conveying roller 23 and the developing roller 21. . The toner layers 22 respectively carried on the developing roller 21 are conveyed to a position facing the image carrier 1 by the developing roller 21, and under the developing electric field formed by the second electric field forming unit 5, the image carrier. The electrostatic latent image on 1 is developed. The development method may be a reversal development method or a regular development method.
After development, the toner remaining on the developing roller 21 is rubbed and disturbed by a magnetic brush formed on the developer conveying roller 23 at a portion facing the developer conveying roller 23 and collected in the developer. .

The direction of movement of the peripheral surface of the developing roller 21 (in the direction of arrow Y3) and the direction of movement of the peripheral surface of the developer conveying roller 23 (that is, in the direction of the sleeve roller 23s) (in the direction of arrow Y1) are opposite in the opposite portion. It is set to be. That is, the moving direction of the developer on the developer conveying roller 23 (that is, on the sleeve roller 23s) and the moving direction of the toner on the developing roller 21 are set so as to be opposite to each other at the opposing portion. Yes. By setting in this way, a higher rubbing / disturbing effect can be obtained, and toner recoverability can be improved.
The developer on the developer transport roller 23 that collects the remaining toner is peeled off from the developer transport roller 23 at a position facing the developer tank 28, collected in the developer tank 28, and mixed and stirred in the developer tank 28. .

Next, each component in the developing device 2 will be described in more detail.
As described above, the developer transport roller 23 includes the magnet roller 23m that is fixedly arranged, and a rotatable sleeve roller 23s that includes the magnet roller 23m. The magnet roller 23m has five magnetic poles N1, S2, N2, N3, and S1 along the rotation direction of the sleeve roller 23s.
Of these magnetic poles, the main magnetic pole N1 is disposed at a position facing the developing roller 21, and the same magnetic pole N2 that generates a repulsive magnetic field for peeling off the developer on the sleeve roller 23s is: It is disposed at a position facing the inside of the developing tank 28.

  As described above, the rotation direction of the developing roller 21 (arrow Y3 direction) is the same as the rotation direction of the sleeve roller 23s of the developer transport roller 23 (arrow Y1 direction), that is, opposite to each other at the opposite portions. Is set to The rotation direction (arrow Y3 direction) is opposite to the rotation direction of the image carrier 1 (arrow Y4 direction), that is, the same direction at the opposite portions.

  The developing tank 28 is formed by a casing 29, and normally contains a stirring and conveying means 26 for feeding the developer 25 to the developer conveying roller 23 while mixing and stirring. A magnetic permeability sensor (not shown) for detecting a toner ratio (weight ratio) in the developer 25 is preferably disposed in the vicinity of the stirring and conveying means 26.

  The developing device 2 normally regulates the amount of developer on the developer transport roller 23 and a replenishment unit for replenishing the developer tank 28 with toner that has been developed into the latent image on the image carrier 1. It has a regulating member 24 for thinning the developer. The replenishing unit includes a toner bottle 3 that stores replenished toner, and a toner replenishing roller 27 for controlling the amount of toner replenished into the developing tank 28.

  Examples of the material used for the developing roller 21 include an aluminum (aluminum) roller that has been subjected to a surface treatment. In addition, on a conductive substrate such as aluminum, for example, polyester resin, polycarbonate resin, acrylic resin, polyethylene resin, polypropylene resin, urethane resin, polyamide resin, polyimide resin, polysulfone resin, polyether ketone resin, vinyl chloride resin, acetic acid A resin coating such as a vinyl resin, a silicone resin, or a fluorine resin, or a rubber coating such as a silicone rubber, urethane rubber, nitrile rubber, natural rubber, or isoprene rubber may be used.

  The coating material is not limited to these. Furthermore, a conductive agent may be added to the bulk or surface of the coating. Examples of the conductive agent include an electronic conductive agent or an ionic conductive agent. Examples of the electronic conductive agent include carbon black such as ketjen black, acetylene black, and furnace black, metal powder, metal oxide fine particles, and the like, but are not limited thereto. Examples of the ionic conductive agent include, but are not limited to, cationic compounds such as quaternary ammonium salts, amphoteric compounds, and other ionic polymer materials. Furthermore, a conductive roller made of a metal material such as aluminum may be used.

[About usable developers]
The developer that can be used in the present invention will be described below.
In the present embodiment, the developer is composed of toner and a carrier for charging the toner.
The toner is not particularly limited, and commonly used known toners can be used. The binder resin contains a colorant and, if necessary, a charge control material or a release material, and the external additive is processed. Can be used. The toner particle size is not limited to this, but is preferably about 3 to 15 μm. In manufacturing such a toner, it can be manufactured by a publicly known method, for example, a pulverization method, an emulsion polymerization method, a suspension polymerization method, or the like.

  The binder resin used in the toner is not limited to this. For example, styrene resin (monopolymer or copolymer containing styrene or a styrene substitution product), polyester resin, epoxy resin, vinyl chloride Resins, phenol resins, polyethylene resins, polypropylene resins, polyurethane resins, silicone resins and the like can be mentioned. It is preferable to use those having a softening temperature in the range of 80 to 160 ° C. and those having a glass transition point in the range of 50 to 75 ° C., depending on the single resin or composite.

  As the colorant, known ones that are generally used can be used. For example, carbon black, aniline black, activated carbon, magnetite, benzine yellow, permanent yellow, naphthol yellow, phthalocyanine blue, first sky blue, ultramarine blue , Rose bengal, lake red, etc., and generally 2 to 20 parts by weight with respect to 100 parts by weight of the binder resin is preferred.

  As the charge control material, known materials can be used. Examples of the charge control material for positively chargeable toner include nigrosine dyes, quaternary ammonium salt compounds, triphenylmethane compounds, imidazole compounds. And polyamine resins. Examples of charge control materials for negatively chargeable toners include metal-containing azo dyes such as Cr, Co, Al, and Fe, salicylic acid metal compounds, alkyl salicylic acid metal compounds, and curlyx allene compounds. In general, the charge control material is preferably used at a rate of 0.1 to 10 weight capital with respect to 100 parts by weight of the binder resin.

  Further, as the above-mentioned mold release material, publicly known ones can be used, for example, polyethylene, polypropylene, carnauba wax, sazol wax and the like can be used alone or in combination of two or more kinds, Generally, it is preferable to use it in the ratio of 0.1-10 weight part with respect to 100 weight part of said binder resin.

  As particles externally added to the toner, commonly used known particles can be used. For the purpose of improving fluidity, for example, silica, titanium oxide, aluminum oxide or the like can be used, and it is particularly preferable to use a water-repellent material such as a silane coupling agent, a titanium coupling agent, or silicon oil. . Such a fluidizing agent is added at a ratio of 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner. The number average primary particle size of the external additive is preferably 10 to 100 nm.

It does not specifically limit as a carrier, The well-known carrier generally used can be used, A binder type carrier, a coat type carrier, etc. can be used. Although it is not limited to this as a carrier particle size, 15-100 micrometers is preferable.
The binder type carrier is obtained by dispersing magnetic fine particles in a binder resin, and positive or negative chargeable fine particles can be fixed to the carrier surface or a surface coating layer can be provided. The charging characteristics such as the polarity of the binder type carrier can be controlled by the material of the binder resin, the chargeable fine particles, the type of the surface coating layer, and the like.

  Examples of the binder resin used for the binder-type carrier include thermoplastic resins such as vinyl resins, polyester resins, nylon resins, polyolefin resins, and the like represented by polystyrene resins, and thermosetting resins such as phenol resins. The

  Magnetic fine particles of the binder type carrier include spinel ferrites such as magnetite and gamma iron oxide, and magnets such as spinel ferrite and barium ferrite containing one or more metals other than iron (Mn, Ni, Mg, Cu, etc.). Plumbite type ferrite, iron or alloy particles having iron oxide on the surface can be used. The shape may be any of a granular shape, a spherical shape, and a needle shape. In particular, when high magnetization is required, it is preferable to use iron-based ferromagnetic fine particles. In consideration of chemical stability, it is preferable to use ferromagnetic fine particles of magnetoplumbite type ferrite such as spinel ferrite and barium ferrite containing magnetite and gamma iron oxide. A magnetic resin carrier having a desired magnetization can be obtained by appropriately selecting the type and content of the ferromagnetic fine particles. The magnetic fine particles are suitably added in an amount of 50 to 90% by weight in the magnetic resin carrier.

Silicone resin, acrylic resin, epoxy resin, fluorine resin, etc. are used as the surface coating material of the binder type carrier, and these resins are coated on the surface and cured to form a coating layer, thereby providing a charge imparting ability. Can be improved.
For example, the charging fine particles or the conductive fine particles can be fixed to the surface of the binder type carrier by, for example, mixing the magnetic resin carrier and the fine particles uniformly, adhering these fine particles to the surface of the magnetic resin carrier, This is performed by applying a strong impact force and fixing the fine particles so as to be driven into the magnetic resin carrier. In this case, the fine particles are not completely embedded in the magnetic resin carrier, but are fixed so that a part thereof protrudes from the surface of the magnetic resin carrier.

  As the chargeable fine particles, an organic or inorganic insulating material is used. Specifically, organic insulating fine particles such as polystyrene, styrene copolymers, acrylic resins, various acrylic copolymers, nylon, polyethylene, polypropylene, fluororesin, and cross-linked products thereof are used. As for the charge level and polarity, a desired level of charge and polarity can be obtained by a material, a polymerization catalyst, a surface treatment, and the like. Further, as the inorganic type, negatively charged inorganic fine particles such as silica and titanium dioxide, and positively charged inorganic fine particles such as strontium titanate and alumina are used.

  On the other hand, a coated carrier is a carrier in which a carrier core particle made of a magnetic material is coated with a resin, and also in a coated carrier, like a binder carrier, positive or negatively chargeable fine particles are fixed on a carrier surface. You can make it. Charging characteristics such as polarity of the coat type carrier can be controlled by the type of the surface coating layer and the chargeable fine particles, and the same material as the binder type carrier can be used. In particular, the same resin as the binder resin of the binder type carrier can be used as the coating resin.

  The charging polarity of the toner by the combination of the toner and the carrier can be easily known from the direction of the electric field for separating the toner from the developer after mixing and stirring each to make the developer. The mixing ratio of the toner and the carrier may be adjusted so as to obtain a desired toner charge amount. The toner ratio is 3 to 50% by weight, preferably 6 to 30% by weight based on the total amount of the toner and the carrier. Is preferred.

[Bias to be applied]
Below, the conditions of bias application that can be used in the present invention will be described.
By the first electric field forming means 4 and the second electric field forming means 5, two conditions can be set when the toner supply portion electric field is an oscillating electric field, and when the developing portion electric field is a direct current electric field and when it is an oscillating electric field. 2A and 2B, FIG. 3 and FIG. 4 show connection examples of the bias power source when the toner is negative and performs reversal development.

  In the connection example shown in FIG. 2A, a first power source S1 connected to the developer conveying roller 23 and a second power source S2 connected to the developing roller 21 are provided, and the second power source S2 is connected to the developing roller. And a second DC voltage having the same polarity as the charging polarity of the toner is applied to the developing roller 21. The first power source S1 includes a DC power source and an AC power source between the developer transport roller 23 and the ground G. The DC power supply applies a first DC voltage having the same polarity as the charging polarity of the toner and higher than the second DC voltage to the developer transport roller 23. The AC power source applies an AC voltage as shown in FIG. 2B between the developer transport roller 23 and the ground G. As a result, in the toner supply region, the negatively charged toner is received from the developer conveying roller 23 by the action of the pulsating electric field formed between the developing roller 21 and the developer conveying roller 23. 21 is electrically attracted. At this time, the positively charged carrier is held by the developer conveying roller 23 by the magnetic force of the fixed magnet inside the developer conveying roller 23 and is not supplied to the developing roller 21. In the developing region, the negative toner held on the developer transport roller 23 is based on the potential difference between the developer transport roller 23 and the electrostatic latent image portion of the image carrier 1. Adhere to.

In the connection example shown in FIG. 3, the second power source S <b> 4 connected to the developing roller 21 also has a DC power source and an AC power source connected between the developing roller 21 and the ground G. The voltage of the AC power source of the first power source S3 connected to the developer transport roller 23 and the voltage of the AC power source of the second power source S4 may be the same or different.
In the connection example shown in FIG. 4, the first power source S5 connected to the developer transport roller 23 has only a DC power source between the developer transport roller 23 and the ground G, and does not have an AC power source. . The second power source S6 connected to the developing roller 21 has a DC power source and an AC power source connected between the developing roller 21 and the ground G.

  In any case, it is necessary to have a potential relationship that allows toner to be supplied from the developer transport roller 23 to the developing roller 21 and that the toner can be developed from the developing roller 21 to the electrostatic latent image portion on the image carrier 1. . The developing unit may be contact development in which the developing roller 21 and the image carrier 1 are in contact with each other via toner, or non-contact in which toner flies in the space between the developing roller 21 and the image carrier 1. Development may be sufficient.

[Experiment]
In the present embodiment, in the hybrid development method, the solid tracking failure that can occur when the image memory is eliminated while directly eliminating the print history on the developing roller 21 (toner carrier) that causes the image memory. Various experiments were conducted from the viewpoint of suppressing occurrence of inconvenience due to (or in addition to this, poor gradation reproducibility, fine line reproducibility, granularity, and image density unevenness).

[Bias conditions for this experiment]
In this experiment, as shown in FIG. 3, the first power source connected to the developer conveying roller 23 and the second power source connected to the developing roller 21 are both DC power sources connected to the ground. And an AC power source.
<Potential relationship between developing roller and photoconductor>
The amplitude of the AC voltage applied to the developing roller 21 was 1500 V, and the frequency was 3 kHz. As shown in FIG. 3, a DC voltage is superimposed on the AC voltage and applied to the developing roller 21, and as can be seen from FIG. 5, the potential of the developing roller 21 is the electrostatic latent image image on the photoreceptor 1. The state of the potential higher than the potential of the portion and the state of the lower potential are alternately and periodically changed. In this experiment, the potential of the electrostatic latent image portion was set to −50V.

<Potential relationship between developer conveying roller and developing roller>
The amplitude of the AC voltage applied to the developing roller 21 was 1000 V, and the frequency was 3 kHz. As shown in FIG. 3, a DC voltage is also superimposed on the AC voltage and applied to the developer transport roller 23. As can be seen from FIG. 5, the potential of the developer transport roller 23 is the potential of the developer roller 21. The state of higher potential and the state of lower potential are alternately and periodically changed.

  As shown in FIG. 5, the voltage applied to the developing roller 21 and the voltage applied to the developer transport roller 23 have the same period (a + b). Further, the low-potential-side duty ratio of the developing roller 21 and the high-potential-side duty ratio of the developer transport roller 23 are the same size (100 × a / (a + b)). In this experiment, the duty ratio a was 40% and the duty ratio b was 60%.

[Average voltage of supply / recovery electric field: ΔV _avg ]
The supply / recovery electric field is composed of a potential difference between a voltage applied to the developing roller 21 and a voltage applied to the developer transport roller 23. As shown in FIG. Becomes a negative value D1, and becomes a positive value D2 in the period indicated by the symbol b. As a result, an electric field in the direction in which the toner is collected from the developing roller 21 to the developer conveying roller 23 and an electric field in the direction in which the toner is supplied from the developer conveying roller 23 to the developing roller 21 alternately Repeatedly configured.

The average value of the potential difference between the voltage applied to the developing roller 21 and the voltage applied to the developer transport roller 23, that is, the average voltage ΔV _avg of the supply / recovery electric field is a positive value. As a result, the supply / recovery electric field becomes an oscillating electric field in the direction in which the toner is supplied from the developer conveying roller 23 to the developing roller 21 on average.
Here, the average voltage ΔV _avg of the supply / recovery electric field is calculated by the following equation (1).
ΔV _avg = (D2 × b−D1 × a) / (a + b) (1)

<Example in this experiment>
In this experiment, a rectangular wave voltage having an amplitude of 1 kV, a DC (direct current) component of −240 V, a negative duty ratio of 60%, and a frequency of 3 kHz was applied to the developer conveying roller 23. On the other hand, a rectangular wave developing bias having an amplitude of 1.5 kV, a DC (direct current) component of −350 V, a negative duty ratio of 40%, and a frequency of 3 kHz was applied to the developing roller 21. The bias applied to each of the rollers 21 and 23 is illustrated as shown in FIG.

As a result, the potential difference in the direction in which the negatively charged toner is supplied from the developer conveying roller 23 to the developing roller 21 is 1140 V, and conversely, the toner on the developing roller 21 is collected in the developer conveying roller 23. It can be seen that the potential difference is 1360V.
In this case, the average potential difference ΔV _avg of the supply / recovery unit is calculated as follows.
ΔV _avg = {(supply side potential difference × supply duty [%]) − (collection side potential difference × recovery duty [%])} / 100
= {(1140 × 60) − (1360 × 40)} / 100
= 140V

[Various conditions for this experiment]
<Toner>
First, the sample toner used in the experiment will be described. In the experiment, a toner manufactured by the following method was prepared.
For 100 parts by weight of a toner base material having a volume average particle diameter of about 6.5 μm prepared by a wet granulation method, 0.2 parts by weight of the first hydrophobic silica and 0.5 parts by weight of the second hydrophobic silica A negative polarity toner was obtained by subjecting 0.5 parts by weight of hydrophobic titanium oxide to a surface treatment for 3 minutes at a mixer rotation speed of 40 m / s using a Henschel mixer (manufactured by Mitsui Metal Mining Co., Ltd.). .
The first hydrophobic silica used here is a silica (# 130: manufactured by Nippon Aerosil Co., Ltd.) having a number average primary particle size of 16 nm and surface-treated with hexamethyldisilazane (HMDS) as a hydrophobizing agent. is there. The second hydrophobic silica is obtained by surface-treating silica (# 90: manufactured by Nippon Aerosil Co., Ltd.) having a number average primary particle size of 20 nm with HMDS. Hydrophobic titanium oxide is an anatase-type titanium oxide having a number average primary particle size of 30 nm and surface-treated with isobutyltrimethoxysilane as a hydrophobizing agent in an aqueous wet process.

<Carrier> -Toner B: A toner having a volume average particle diameter of about 9 μm prepared by wet granulation. The carrier is a coated carrier in which an acrylic resin coat is formed on carrier core particles made of a magnetic material. Used a carrier for bizhub C350 manufactured by Konica Minolta Business Technologies, Inc. having a size of about 33 μm.

<Developing device>
As the developing device, the developing device 2 having the configuration shown in FIG. 1 was used, and a developer containing the above-described toner and carrier was used. The toner ratio in the developer was 8%. In this case, the toner ratio is the ratio of the total amount of toner and external additive to the total amount of developer (hereinafter the same).
As the image forming apparatus, a modified version of the color multifunction machine bizhub C650 manufactured by Konica Minolta Business Technologies was used.

The developing roller 21 is an aluminum roller with an alumite treatment on the surface, and the closest gap between the developer conveying roller 23 and the developing roller 21 is 0.4 mm. Thus, the electric field in the toner supply direction formed between the developer conveying roller 23 and the developing roller 21 is 1140 V / 0.4 mm = 2.85 × 10 ⁶ V / m. The spacing between the regulating member 24 and the developer transport roller 23 is 0.4 mm so that the magnetic brush on the developer transport roller 23 slides on the development roller 21, and the developer amount per unit area on the developer transport roller 23 Was 400 g / m ² . The developer moving direction on the developer conveying roller 23 and the toner moving direction on the developing roller 21 are opposite to each other at the facing portion. Further, the background portion potential of the electrostatic latent image formed on the photoreceptor (image carrier) 1 is −550 V, the image portion potential is −50 V, and the gap at the closest portion between the photoreceptor 1 and the developing roller 21 is. Was 0.14 mm.

Here, the ratio of the peripheral speed of the developing roller 21 to the peripheral speed of the photoconductor (image carrier) 1 is Rd (development-side peripheral speed ratio: Rd = peripheral speed of the developing roller 21 / peripheral speed of the photoconductor 1). Let Q [g / m ² ] be the toner conveyance amount (toner carrying amount per unit area) on the developing roller 21.

[Image memory and solid traceability test]
The test conditions were set by assigning the toner transport amount Q on the developing roller and the developing side peripheral speed ratio Rd in a matrix, and a test for evaluating the image memory and solid followability and the heat generation of the developing device was performed. In this test, evaluation of image memory, solid followability, and heat generation of the developing device was performed as follows.
<Evaluation of image memory>
The image memory is evaluated by printing a halftone image after printing a memory evaluation image chart image (an image in which a solid image portion and a blank image portion are mixed), and whether or not the image memory is generated in the halftone image. Was confirmed by visual inspection. Those in which no image memory was confirmed were judged as ◯ (good), and those in which the image memory was confirmed were judged as x (bad).
FIGS. 16A and 16B show an example of “without image memory” (FIG. 16A) and an example of “with image memory” (FIG. 16B), respectively.

<Evaluation of solid traceability>
The solid followability was evaluated by visually checking whether or not there is a density difference between the leading edge of image printing and the trailing edge of image printing when a solid image was printed. A sample in which no difference in density was confirmed was judged as ◯ (good), and a sample in which a density difference was confirmed was judged as x (defect).
FIGS. 17A and 17B show an example of “good solid tracking” (FIG. 17A) and an example of “solid insufficient tracking” (FIG. 17B), respectively.
<Evaluation of heat generation of developing device>
The evaluation of the exothermic property of the developing device is performed by detecting the ambient temperature in the vicinity of the developing device 2 when a predetermined number of solid images are printed with a temperature sensor and confirming whether or not the ambient temperature is lower than the predetermined temperature. It was. When the temperature was lower than the predetermined temperature, it was judged as ◯ (good).

  The image quality evaluation in the product can be performed by providing a density measuring device (not shown) for detecting the image density on the photosensitive member or the intermediate transfer member. By detecting the image density with the density measuring device, it is possible to determine whether the image memory and the solid followability are good or bad as with visual observation. The sensor used for the concentration measuring device may be either an optical sensor or a potential sensor, or both.

The toner transport amount Q on the developing roller is changed in units of 1 [g / m2] in the range of 1 to 5 [g / m2], and the development side peripheral speed ratio Rd is increased by 0.5 in the range of 1 to 4. The test conditions were set by allocating them in a matrix, and a test for evaluating the image memory and the solid followability and the heat generation of the developing device was conducted.
The test results were as shown in Table 1 (image memory), Table 2 (solid followability) and Table 3 (developing device heat generation).

  From the test results in Table 1, it was found that the image memory tends to occur when the toner conveyance amount Q on the developing roller increases, but is not affected by the development-side peripheral speed ratio Rd. Further, from the test results of Table 2, it was found that the solid followability is affected by both the toner conveyance amount Q on the developing roller and the development side peripheral speed ratio Rd. Further, from the test results in Table 3, it was found that the exothermic property of the developing device 2 is largely not affected by the toner conveyance amount Q on the developing roller, but greatly influenced by the development side peripheral speed ratio Rd.

Here, in order to satisfy the image memory, the toner transport amount Q on the developing roller may be set small (see Table 1). The larger one is advantageous (see Table 2). Therefore, the toner transport amount Q on the developing roller may be set to the maximum value within a range that satisfies the image memory in consideration of solid followability.
Further, in order to satisfy the solid followability, the development-side peripheral speed ratio Rd should be set large (see Table 2). However, increasing the development-side peripheral speed ratio Rd increases the printing speed. Unless slowing down (lowering the rotational speed of the photosensitive member 1), the rotational speed of the developing roller 21 is increased, so that the motor size, heat generation (see Table 3), and durability become problems.

Therefore, it is important how to perform image adjustment for the image memory and the solid followability after suppressing the heat generation of the developing device 2.
In this embodiment, first, the toner conveyance amount Q on the developing roller is set from the image memory under an arbitrary development-side peripheral speed ratio Rd fixing condition, and then the development-side peripheral speed ratio Rd is set from the solid followability. By doing so, it was found that a condition that satisfies both the image memory and the solid followability can be found.

[Example 1]
In the first embodiment, as shown in FIG. 7, after performing image memory adjustment (image adjustment for image memory: step # 11), solid followability adjustment (image adjustment for solid followability: step # 12) is performed. Image adjustment is performed according to the control flow (1).
a) In the image memory adjustment, the toner conveyance on the developing roller is maximized within the range satisfying the image memory under the condition that the development side peripheral speed ratio Rd is fixed to 1.5 (Rd = 1.5), for example. A quantity Q (Q = 4) was set (see Table 1). As can be seen from Table 1, when the image memory is adjusted, the maximum value of the toner conveyance amount Q on the developing roller is determined to be 4 (Q = 4) regardless of the developing-side peripheral speed ratio Rd.
b) For the solid followability adjustment, it is possible to select a development-side peripheral speed ratio Rd = 2 or more that satisfies the toner conveyance amount Q = 4 on the developing roller and satisfies the solid followability (see Table 2). ). However, as can be seen from Table 3, if the development-side peripheral speed ratio Rd is 3.5 or more, the heat generation property of the developing device becomes a problem. Therefore, considering this point, the development-side peripheral speed ratio Rd is 2 In the above, it was set to less than 3.5 (Rd = 2, 2.5, or 3).

  As described above, according to the control flow (1) for performing the solid followability adjustment after the image memory adjustment, the toner conveyance amount Q on the developing roller is 4 (Q = 4), and the development-side peripheral speed ratio Rd is By setting any one of 2, 2.5, and 3 (Rd = 2, 2.5, 3), it is preferable to satisfy both the image memory and the solid traceability while suppressing the heat generation of the developing device. Image adjustment can be performed. The image adjustment control as described above is performed by an image adjustment function of a control unit (not shown) of the image forming apparatus according to the present embodiment.

[Comparative Example 1]
As shown in FIG. 8, in the first comparative example, in contrast to the first embodiment, the solid-state tracking adjustment (step # 21) is performed and then the image memory adjustment (step # 22) is performed. The image adjustment is performed.
a) For the solid followability, it is advantageous that the toner transport amount Q on the developing roller is large (see Table 2). In this case, the toner transport amount Q on the developing roller is set to 5 when adjusting the solid followability. Under the setting (Q = 5), considering the exothermic property of the developing device (see Table 3), the developing-side peripheral speed ratio Rd is 1.5 or more and less than 3.5 (Rd = 1.5, 2 , 2.5, or 3).
b) The image memory adjustment is set to the toner transport amount Q (Q = 4) on the developing roller that is the maximum within the range satisfying the image memory (see Table 1).

In the image adjustment method according to Comparative Example 1, when the toner conveyance amount Q on the developing roller is Q = 4 and the development side peripheral speed ratio Rd is 1.5, the image memory is ◯ (good), but the solid followability is good. Becomes x (defect), and both qualities cannot be satisfied.
That is, as in the first embodiment, when image adjustment is performed according to the control flow (1) in which solid followability adjustment is performed after image memory adjustment is performed, conditions satisfying both qualities can be found efficiently. I understood.

The area that satisfies the quality of both image memory and solid traceability changes depending on the developer, the durability history of the photoconductor and the environment. Therefore, it is necessary to perform the image adjustment described above during image stabilization. is there. However, since the tendency of the influence of the toner conveyance amount Q on the developing roller and the development-side peripheral speed ratio Rd on both qualities does not change, the same control is possible.
In this experiment, the photosensitive member and the developing roller rotate in the same direction on the peripheral surface, and the developing roller and the developer transport roller rotate in the opposite directions on the peripheral surface. Is not particularly limited.

FIG. 9 is a graph showing the results of examining the relationship between the average voltage ΔV _avg of the supply / recovery electric field and the toner conveyance amount Q on the developing roller, using the developing side peripheral speed ratio Rd as a parameter. As can be seen from this graph, the toner transport amount Q on the developing roller is uniquely determined with respect to the average voltage ΔV _avg of the supply / recovery electric field, and there is a positive correlation between the two. Therefore, it can be understood that the toner conveyance amount Q on the developing roller can be easily adjusted by adjusting the average voltage ΔV _avg of the supply and recovery electric field.

FIG. 10 is a graph showing the results of examining the relationship between the average voltage ΔV _avg of the supply / recovery electric field and the DC voltage component VSdc [V] applied to the developer transport roller. As is apparent from the above equation (1), the average voltage ΔV _avg of the supply / recovery electric field varies depending on the voltage applied to the developer transport roller. In this experiment, the DC voltage component VSdc applied to the developer transport roller is changed. The average voltage ΔV _avg of the supply / recovery electric field is adjusted by [V]. The adjustment of the average voltage ΔV _avg of the supply / recovery electric field is not limited to the DC voltage component VSdc applied to the developer transport roller.

  Next, a test was conducted to examine the relationship between the rotation speed of the developing roller and the development-side peripheral speed ratio Rd while maintaining the rotation speed of the photosensitive member constant. The test results are shown in Table 4. In this test, this test was performed using an image forming apparatus having a process speed of 310 mm / sec and a developing roller diameter of 18 mm.

  From Table 4, it can be seen that the development-side peripheral speed ratio Rd can be controlled by the rotation speed of the developing roller. Table 1 also shows that the toner transport amount Q on the developing roller hardly changes even when the developing-side peripheral speed ratio Rd is changed. This is because the toner conveyance amount Q on the developing roller indicates a state in which the toner amount on the developing roller passes through the supply / recovery section many times, and the supply / recovery varies depending on the development-side peripheral speed ratio Rd. It is because it is not influenced by the time in the section. Further, in the two-component development, the potential difference between the developing roller and the developer conveying roller determines the toner conveying amount Q on the developing roller.

  As described above, even if the developing side peripheral speed ratio Rd is changed while keeping the rotation speed of the photosensitive member constant, it can be treated as a factor independent of the toner transport amount Q on the developing roller. Of course, when the rotation speed of the photosensitive member is changed while the rotation speed of the developing roller is kept constant, the development-side peripheral speed ratio Rd becomes a factor independent of the toner conveyance amount Q on the development roller.

  When a test condition is set by assigning the toner conveyance amount Q on the developing roller and the development-side peripheral speed ratio Rd in a matrix, and a test for evaluating the image memory and solid followability and the heat generation of the developing device is performed. In addition, tone reproducibility, fine line reproducibility, graininess, and image density unevenness were also evaluated.

[Evaluation of gradation reproducibility]
Gradation reproducibility is evaluated by printing on a gradation reproducibility evaluation image chart (an image chart in which the print density is adjusted from solid to white in stages) and visually confirming whether or not the gradation reproducibility is good. I went there. Those in which the gradation reproducibility was confirmed to be clear were judged as ◯ (good), and those in which the gradation reproducibility was unclear were judged as x (poor).
FIGS. 18A and 18B show an example of “good gradation reproducibility” (FIG. 18A) and an example of “not good gradation reproducibility” (FIG. 18B), respectively. Table 5 shows the results of the gradation reproducibility test.

From the test results in Table 5, the gradation reproducibility is affected by both the toner conveyance amount Q on the developing roller and the development side peripheral speed ratio Rd, and it is advantageous that the development side peripheral speed ratio Rd is small. I understood.
Also, from Tables 1, 2 and 5, it has been found that there are conditions that favorably satisfy all of the image memory, solid followability and gradation reproducibility.

[Example 2]
In the second embodiment, as shown in FIG. 11, after the image memory adjustment (step # 31), the solid followability adjustment (step # 32) is performed, and then the gradation reproducibility adjustment (gradation reproducibility) is performed. The image adjustment is performed according to the control flow (3) in which the image adjustment for step # 33) is performed.
a) In the image memory adjustment, the toner conveyance amount Q (Q = 4) on the developing roller that is the maximum within the range satisfying the image memory under the condition that the development side peripheral speed ratio Rd is fixed to Rd = 1, for example. Was set (see Table 1). As can be seen from Table 1, when adjusting the image memory, the maximum value of the toner conveyance amount Q on the developing roller is set to 4 regardless of the developing-side peripheral speed ratio Rd, as described above. .
b) In the solid followability adjustment, the lower limit (Rd = 2) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner conveyance amount Q = 4 on the developing roller and satisfies the solid followability ( (See Table 2).

c) In the gradation reproducibility adjustment, the upper limit value (Rd = 2.5) of the development-side peripheral speed ratio Rd is within a range that satisfies the toner conveyance amount Q = 4 on the developing roller and satisfies the gradation reproducibility. Was determined (see Table 5). However, as described above, if the development-side peripheral speed ratio Rd = 3.5 or more, the heat generation property of the developing device becomes a problem (see Table 3), and this point needs to be considered depending on the conditions.
d) The development-side peripheral speed ratio Rd was set to a range (2 ≦ Rd ≦ 2.5) that is not less than the lower limit (2) and not more than the upper limit (2.5). That is, the development-side peripheral speed ratio Rd = 2 or 2.5 is set.

  As described above, the toner conveyance amount Q on the developing roller is Q = 4, and the development-side peripheral speed ratio Rd = 2 or 2.5, thereby suppressing the heat generation of the developing device 2 and the image memory. Therefore, it is possible to perform image adjustment that can satisfactorily satisfy all of the solid followability and gradation reproducibility. Further, when performing such image adjustment, efficient image adjustment can be performed by first performing image memory adjustment.

In the above description, the tone reproducibility adjustment (step # 33) is performed after the solid followability adjustment (step # 32). However, the image memory adjustment (step # 31) is only performed first. For example, the order of the solid followability adjustment and the gradation reproducibility adjustment may be performed first.
Among the good results obtained in Example 1, both the image memory and the solid follow-up are good when the toner transport amount Q on the developing roller is Q = 4 and the development-side peripheral speed ratio Rd is 3. ○), but the gradation reproducibility is poor (x).

[Evaluation of fine line reproducibility]
Evaluation of fine line reproducibility was performed by printing on an image chart for thin line reproducibility evaluation (an image chart in which fine lines were provided between blank paper portions) and visually confirming whether fine line reproducibility was good. Those in which the fine line reproducibility was confirmed to be clear were judged as ◯ (good), and those in which the fine line reproducibility was unclear were judged as x (poor). The results of this fine line reproducibility test are shown in Table 6.
FIGS. 19A and 19B show an example of “good fine line reproducibility” (FIG. 19A) and an example of “poor thin line reproducibility” (FIG. 19B), respectively. In addition, Table 6 shows the results of the fine line reproducibility test.

From the test results in Table 6, it is understood that the fine line reproducibility is affected by both the toner conveyance amount Q on the developing roller and the development side peripheral speed ratio Rd, and it is advantageous that the development side peripheral speed ratio Rd is small. It was.
Also, from Tables 1, 2 and 6, it has been found that there are conditions that satisfy all of the image memory, solid followability and fine line reproducibility.

[Example 3]
In the third embodiment, as shown in FIG. 12, after performing image memory adjustment (step # 41), solid followability adjustment (step # 42) is performed, and then fine line reproducibility adjustment (about gradation reproducibility) is performed. The image adjustment is performed according to the control flow (4) for performing the image adjustment: step # 43).
a) In the image memory adjustment, the toner conveyance amount Q (Q = 4) on the developing roller that is the maximum within the range satisfying the image memory under the condition that the development side peripheral speed ratio Rd is fixed to Rd = 1, for example. Was set (see Table 1). As described above, at the time of image memory adjustment, the maximum value of the toner conveyance amount Q on the developing roller is determined to be 4 regardless of the developing-side peripheral speed ratio Rd.
b) In the solid followability adjustment, the lower limit (Rd = 2) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner conveyance amount Q = 4 on the developing roller and satisfies the solid followability ( (See Table 2).

c) In fine line reproducibility adjustment, the upper limit (Rd = 2.5) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner transport amount Q = 4 on the developing roller and satisfies the fine line reproducibility. (See Table 6). However, as described above, if the development-side peripheral speed ratio Rd = 3.5 or more, the heat generation property of the developing device becomes a problem (see Table 3), and this point needs to be considered depending on the conditions.
d) The development-side peripheral speed ratio Rd was set to a range (2 ≦ Rd ≦ 2.5) that is not less than the lower limit (2) and not more than the upper limit (2.5). That is, the development-side peripheral speed ratio Rd = 2 or 2.5 is set.

  As described above, the toner conveyance amount Q on the developing roller is Q = 4, and the development-side peripheral speed ratio Rd = 2 or 2.5, thereby suppressing the heat generation of the developing device 2 and the image memory. Therefore, it is possible to perform image adjustment that can satisfactorily satisfy all of the solid followability and fine line reproducibility. Further, when performing such image adjustment, efficient image adjustment can be performed by first performing image memory adjustment.

In the above description, the fine line reproducibility adjustment (step # 43) is performed after the solid followability adjustment (step # 42). However, as long as the image memory adjustment (step # 41) is performed first. The order of the solid followability adjustment and the line-of-sight reproducibility adjustment may be performed first.
Among the good results obtained in Example 1, both the image memory and the solid follow-up are good when the toner transport amount Q on the developing roller is Q = 4 and the development-side peripheral speed ratio Rd is 3. ○), but the fine line reproducibility is poor (x).

[Evaluation of graininess]
Graininess was evaluated by taking in an image chart for tone reproducibility evaluation (an image chart in which the print density was adjusted from solid to white in stages) with a scanner, and evaluating the variation in dots of each density. Those with little variation were judged as ◯ (good), and those with much variation were judged as x (bad).
20A and 20B show an example of “good graininess” (FIG. 20A) and an example of “poor graininess” (FIG. 20B), respectively. Table 7 shows the results of the graininess test.

From the test results of Table 7, it was found that the granularity is affected by both the toner conveyance amount Q on the developing roller and the development side peripheral speed ratio Rd, and it is advantageous that the development side peripheral speed ratio Rd is small. .
Further, from Tables 1, 2 and 7, it was also found that there are conditions that favorably satisfy all of the image memory, solid followability and graininess.

[Example 4]
In the fourth embodiment, as shown in FIG. 13, after performing image memory adjustment (step # 51), solid followability adjustment (step # 52) is performed, and thereafter, graininess adjustment (image adjustment for graininess) is performed. : Image adjustment is performed according to the control flow (5) for performing step # 53).
a) In the image memory adjustment, the toner conveyance amount Q (Q = 4) on the developing roller that is the maximum within the range satisfying the image memory under the condition that the development side peripheral speed ratio Rd is fixed to Rd = 1, for example. Was set (see Table 1). As described above, at the time of image memory adjustment, the maximum value of the toner conveyance amount Q on the developing roller is determined to be 4 regardless of the developing-side peripheral speed ratio Rd.
b) In the solid followability adjustment, the lower limit (Rd = 2) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner conveyance amount Q = 4 on the developing roller and satisfies the solid followability ( (See Table 2).

c) In the graininess adjustment, the upper limit value (Rd = 2.5) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner transport amount Q = 4 on the developing roller and satisfies the graininess ( (See Table 7). However, as described above, if the development-side peripheral speed ratio Rd = 3.5 or more, the heat generation property of the developing device becomes a problem (see Table 3), and this point needs to be considered depending on the conditions.
d) The development-side peripheral speed ratio Rd was set to a range (2 ≦ Rd ≦ 2.5) that is not less than the lower limit (2) and not more than the upper limit (2.5). That is, the development-side peripheral speed ratio Rd = 2 or 2.5 is set.

  As described above, the toner conveyance amount Q on the developing roller is Q = 4, and the development-side peripheral speed ratio Rd = 2 or 2.5, thereby suppressing the heat generation of the developing device 2 and the image memory. Therefore, it is possible to perform image adjustment capable of satisfying all of the solid followability and graininess. Further, when performing such image adjustment, efficient image adjustment can be performed by first performing image memory adjustment.

In the above description, the granularity adjustment (step # 53) is performed after the solid followability adjustment (step # 52). However, if the image memory adjustment (step # 51) is performed first, Any order of the solidity tracking adjustment and the graininess adjustment may be performed first.
Among the good results obtained in Example 1, both the image memory and the solid follow-up are good when the toner transport amount Q on the developing roller is Q = 4 and the development-side peripheral speed ratio Rd is 3. ○), but the gradation reproducibility is poor (x).

[Evaluation of uneven image density]
The evaluation of the image density unevenness was performed by visually checking whether or not there is a density difference within the page in each test chart (solid image, half image). Those in which the density difference could not be confirmed were judged as ◯ (good), and those in which the density difference could be confirmed were judged as x (bad).
FIGS. 21A and 21B show an example of “no image density unevenness” (FIG. 21A) and an example of “image density unevenness” (FIG. 21B), respectively. Table 8 shows the results of the image density unevenness test.

From the test results in Table 8, it can be seen that the image density unevenness is affected by both the toner conveyance amount Q on the developing roller and the development side peripheral speed ratio Rd, and it is advantageous that the development side peripheral speed ratio Rd is small. It was.
Further, from Tables 1, 2 and 8, it was also found that there exist conditions that satisfy all of the image memory, the solid followability and the image density unevenness suitably.

[Example 5]
In the fifth embodiment, as shown in FIG. 14, after the image memory adjustment (step # 61), the solid followability adjustment (step # 62) is performed, and then the graininess adjustment (image adjustment for the graininess) is performed. : Image adjustment is performed according to the control flow (6) for performing step # 63).
a) In the image memory adjustment, the toner conveyance amount Q (Q = 4) on the developing roller that is the maximum within the range satisfying the image memory under the condition that the development side peripheral speed ratio Rd is fixed to Rd = 1, for example. Was set (see Table 1). As described above, at the time of image memory adjustment, the maximum value of the toner conveyance amount Q on the developing roller is determined to be 4 regardless of the developing-side peripheral speed ratio Rd.
b) In the solid followability adjustment, the lower limit (Rd = 2) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner conveyance amount Q = 4 on the developing roller and satisfies the solid followability ( (See Table 2).

c) In the image density unevenness adjustment, the upper limit value (Rd = 2) of the development-side peripheral speed ratio Rd is determined within a range that satisfies the toner transport amount Q = 4 on the developing roller and satisfies the image density unevenness (Rd = 2). (See Table 8). However, as described above, since the heat generation property of the developing device 2 becomes a problem when the developing side peripheral speed ratio Rd is 3.5 or more (see Table 3), this point needs to be considered depending on conditions.
d) The development-side peripheral speed ratio Rd was set to a range between the lower limit (2) and the upper limit (2) (lower limit ≦ Rd ≦ upper limit). That is, the development side peripheral speed ratio Rd = 2 is set.

  In this way, by setting the toner transport amount Q on the developing roller to Q = 4 and the developing-side peripheral speed ratio Rd = 2, heat generation of the developing device 2 can be suppressed, and the image memory, solid followability, and image Image adjustment that can satisfactorily satisfy all of the density unevenness can be performed. Further, when performing such image adjustment, efficient image adjustment can be performed by first performing image memory adjustment.

In the above description, the image density unevenness adjustment (step # 63) is performed after the solid followability adjustment (step # 62). However, as long as the image memory adjustment (step # 61) is performed first. Any order of the solid followability adjustment and the image density unevenness adjustment may be performed first.
Of the good results obtained in the first embodiment, when the toner transport amount Q on the developing roller is Q = 4 and the development-side peripheral speed ratio Rd = 2.5 and Rd = 3, the image memory and the solid image Both followability is good (◯), but the image density unevenness is poor (×).

As can be seen from Table 5, Table 6, Table 7, and Table 8, with respect to gradation reproducibility, fine line reproducibility, graininess, and image density unevenness, it is advantageous that the developing-side peripheral speed ratio Rd is smaller. On the other hand, as can be seen from Table 2, it is advantageous for the solid followability to have a larger development-side peripheral speed ratio Rd.
Tables 1 and 2 and Tables 5 to 8 also show that there are conditions that satisfy all of image memory, solid tracking, gradation reproducibility, fine line reproducibility, graininess, and image density unevenness. It was.

Therefore, how efficient is it to perform image adjustment that satisfies all of image memory, solid traceability, gradation reproducibility, fine line reproducibility, graininess, and image density unevenness while suppressing heat generation of the developing device? It is important to do well.
In this embodiment, with the rotation speed of the developing roller 21 set to the minimum speed in the use range, first, the toner conveyance amount Q on the developing roller from the image memory is set under an arbitrary developing-side peripheral speed ratio Rd fixing condition. A condition for satisfying all the quality optimally and optimally by setting and then increasing the development side peripheral speed ratio Rd little by little to obtain the lower limit value of the development side peripheral speed ratio Rd that satisfies solid followability I found out that

[Example 7]
In the seventh embodiment, as shown in FIG. 15, the rotation speed of the developing roller 21 is set to the minimum speed in the use range (step # 71), and in this state, first, image memory adjustment (step # 72) is performed. After that, image adjustment is performed according to a control flow (7) in which solid followability adjustment (step # 73) is performed while gradually increasing the development-side peripheral speed ratio Rd.
a) Rd = 1 is set as the development-side peripheral speed ratio Rd corresponding to the minimum rotation speed in the usage range of the developing roller 21.
b) In the image memory adjustment, the toner transport amount Q (Q = 4) on the developing roller that is the maximum within the range satisfying the image memory under the condition that the development-side peripheral speed ratio Rd is set to 1 as described above. ) Was set (see Table 1).

c) When adjusting the solid followability, the development side peripheral speed ratio Rd is increased by a predetermined amount (in this case, in 0.5 increments) under the toner transport amount Q = 4 on the developing roller. went.
<First stage>: Development-side peripheral speed ratio Rd = 1
In this case, the solid followability is x (defective) (see Table 2).
<Second stage>: Development-side peripheral speed ratio Rd = 1.5
Also in this case, the solid followability is x (defective) (see Table 2).
<Third stage>: Development-side peripheral speed ratio Rd = 2
In this case, the solid followability is ◯ (good) (see Table 2).

  Therefore, the toner transport amount Q on the developing roller is set to 4 and the developing side peripheral speed ratio Rd is set to 2. As can be seen from Tables 2 and 5-8, according to this setting, not only solid followability but also gradation reproducibility, fine line reproducibility, graininess, and image density unevenness are good (good). .

  As described above, the toner transport amount Q on the developing roller Q = 4 and the development-side peripheral speed ratio Rd = 2 make it possible to suppress the heat generation of the developing device, and to suppress the image memory, solid followability, gradation All of reproducibility, fine line reproducibility, graininess, and image density unevenness can be satisfactorily satisfied, and when performing such image adjustment, efficient image adjustment is performed by first performing image memory adjustment. be able to. Further, with the rotation speed of the developing roller 21 set to the lowest speed in the usable range, first, image memory adjustment is performed, and then the developing side peripheral speed ratio Rd is gradually increased while satisfying the solid followability. By obtaining the lower limit value of the peripheral speed ratio Rd, it is possible to perform image adjustment that satisfies all the quality suitably and most efficiently.

[Image quality evaluation in products]
The image quality evaluation in the product can be performed by arranging a density measuring device for detecting the image density on the photosensitive member or the intermediate transfer member.
By detecting the image density with the density measuring device, it is possible to determine whether the image memory and the solid followability are good or bad as with visual observation. The sensor used for the concentration measuring device may be either an optical sensor or a potential sensor, or both.

The gradation reproducibility can be evaluated based on whether or not the density of each step chart is high and whether the density difference is large. Fine line reproducibility depends on whether or not the density difference can be detected by lowering the rotational speed of the rotating body (photoreceptor or intermediate transfer belt) corresponding to the sensor at the time of density measurement compared to normal printing, improving the detection accuracy. Can be evaluated. Graininess can be evaluated by capturing a printed image with a scanner attached to the image forming apparatus. Further, the image density unevenness can be evaluated by measuring the density at a plurality of locations within the page to determine whether or not there is a density difference within the page in each test chart (solid image, half image).
The image adjustment control as described above is performed by the image adjustment function of the control unit of the image forming apparatus according to the present embodiment.

  As described above, according to the present embodiment, the detection means for detecting the image memory and solid traceability (or gradation reproducibility, fine line reproducibility, graininess, and image density unevenness in addition to these), And an image memory and control means for controlling solid reproducibility (or gradation reproducibility, fine line reproducibility, graininess, and image density unevenness in addition to these), and the control means includes a toner carrier (developing roller 21). ) While controlling the image memory by controlling the toner transport amount Q above, the developing side peripheral speed ratio which is the ratio of the peripheral speed of the developing roller 21 to the peripheral speed of the electrostatic latent image carrier (photosensitive member 1). By controlling the Rd, the solid followability (or gradation reproducibility, fine line reproducibility, graininess, and image density unevenness) is controlled, and after the adjustment of the image memory, the solid followability (or in addition thereto) is controlled. Gradation Adjustment of actuality, fine line reproducibility, graininess, and image density unevenness), which can occur when the image memory is eliminated while directly eliminating the print history on the developing roller 21 that causes the image memory. In addition, it is possible to suppress the occurrence of inconvenience due to a solid follow-up defect (or in addition to this, a gradation reproducibility defect, a fine line reproducibility defect, a graininess defect, and an image density unevenness defect).

Although the above description has been for the case where only one developing roller 21 is provided, the present invention can also be effectively applied to a case where a plurality of developing rollers are provided.
Thus, it goes without saying that the present invention is not limited to the above-described embodiments, and that changes and improvements can be made without departing from the scope of the invention.

  INDUSTRIAL APPLICABILITY The present invention is effectively used as an image forming apparatus used for electrophotographic image formation applicable to, for example, a copying machine, a facsimile machine, a printer, or a multifunction machine of these, and an image adjustment method in such an image forming apparatus. be able to.

1 Photoconductor (image carrier)
2 Developing device 4 First electric field forming means 5 Second electric field forming means 21 Developing roller (toner carrier)
22 toner layer 23 developer transport roller (developer carrier)
25 Developer M1 Image forming apparatus Q Toner conveyance amount on developing roller Rd Development-side peripheral speed ratio ΔV _avg Average potential difference in toner supply / recovery unit

Claims (14)

a) a developer carrying member carrying a developer containing a non-magnetic toner and a magnetic carrier; b) an electrostatic latent image facing the developer carrying member through a supply / recovery region and through the developing region. A toner carrier disposed opposite to the carrier and carrying the toner supplied from the developer carrier in the supply and recovery region; and c) developing between the developer carrier and the toner carrier. A first electric field for supplying and collecting toner is formed between the agent carrier and the toner carrier, and the toner carrier is provided between the toner carrier and the electrostatic latent image carrier. An electric field forming means for forming a second electric field for transferring toner from the body to a latent image portion on the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. An image forming apparatus comprising:
A detection means for detecting the image memory and the solid followability, respectively, and a control means for controlling the image memory and the solid followability, respectively.
The control means controls the image memory by controlling the amount of toner carried per unit area on the toner carrier, while the peripheral speed of the toner carrier relative to the circumferential speed of the electrostatic latent image carrier. By controlling the development side peripheral speed ratio that is the ratio, the solid followability is controlled,
Furthermore, the control means has a control flow for adjusting the solid followability after adjusting the image memory.
An image forming apparatus. a) a developer carrying member carrying a developer containing a non-magnetic toner and a magnetic carrier; b) an electrostatic latent image facing the developer carrying member through a supply / recovery region and through the developing region. A toner carrier disposed opposite to the carrier and carrying the toner supplied from the developer carrier in the supply and recovery region; and c) developing between the developer carrier and the toner carrier. A first electric field for supplying and collecting toner is formed between the agent carrier and the toner carrier, and the toner carrier is provided between the toner carrier and the electrostatic latent image carrier. An electric field forming means for forming a second electric field for transferring toner from the body to a latent image portion on the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. An image forming apparatus comprising:
An image memory, solid tracking capability, and gradation reproducibility detection means; and image memory, solid tracking capability and gradation reproducibility control means, respectively.
The control means controls the image memory by controlling the amount of toner carried per unit area on the toner carrier, while the peripheral speed of the toner carrier relative to the circumferential speed of the electrostatic latent image carrier. By controlling the development side peripheral speed ratio that is the ratio, the solid followability and gradation reproducibility are controlled,
Furthermore, the control means has a control flow for adjusting solid followability and gradation reproducibility after first adjusting the image memory.
An image forming apparatus. a) a developer carrying member carrying a developer containing a non-magnetic toner and a magnetic carrier; b) an electrostatic latent image facing the developer carrying member through a supply / recovery region and through the developing region. A toner carrier disposed opposite to the carrier and carrying the toner supplied from the developer carrier in the supply and recovery region; and c) developing between the developer carrier and the toner carrier. A first electric field for supplying and collecting toner is formed between the agent carrier and the toner carrier, and the toner carrier is provided between the toner carrier and the electrostatic latent image carrier. An electric field forming means for forming a second electric field for transferring toner from the body to a latent image portion on the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. An image forming apparatus comprising:
A detection means for detecting image memory, solid traceability and fine line reproducibility; and a control means for controlling the image memory, solid traceability and fine line reproducibility, respectively.
The control means controls the image memory by controlling the amount of toner carried per unit area on the toner carrier, while the peripheral speed of the toner carrier relative to the circumferential speed of the electrostatic latent image carrier. By controlling the development side peripheral speed ratio that is the ratio, the solid followability and fine line reproducibility are controlled,
Further, the control means has a control flow for adjusting the solid followability and fine line reproducibility after adjusting the image memory for the first time.
An image forming apparatus. a) a developer carrying member carrying a developer containing a non-magnetic toner and a magnetic carrier; b) an electrostatic latent image facing the developer carrying member through a supply / recovery region and through the developing region. A toner carrier disposed opposite to the carrier and carrying the toner supplied from the developer carrier in the supply and recovery region; and c) developing between the developer carrier and the toner carrier. A first electric field for supplying and collecting toner is formed between the agent carrier and the toner carrier, and the toner carrier is provided between the toner carrier and the electrostatic latent image carrier. An electric field forming means for forming a second electric field for transferring toner from the body to a latent image portion on the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. An image forming apparatus comprising:
A detection means for detecting the image memory, the solid followability and the granularity, respectively, and a control means for controlling the image memory, the solid followability and the granularity,
The control means controls the image memory by controlling the amount of toner carried per unit area on the toner carrier, while the peripheral speed of the toner carrier relative to the circumferential speed of the electrostatic latent image carrier. By controlling the development side peripheral speed ratio that is the ratio, the solid followability and graininess are controlled,
Further, the control means has a control flow for adjusting the solid followability and the graininess after adjusting the image memory for the first time.
An image forming apparatus. a) a developer carrying member carrying a developer containing a non-magnetic toner and a magnetic carrier; b) an electrostatic latent image facing the developer carrying member through a supply / recovery region and through the developing region. A toner carrier disposed opposite to the carrier and carrying the toner supplied from the developer carrier in the supply and recovery region; and c) developing between the developer carrier and the toner carrier. A first electric field for supplying and collecting toner is formed between the agent carrier and the toner carrier, and the toner carrier is provided between the toner carrier and the electrostatic latent image carrier. An electric field forming means for forming a second electric field for transferring toner from the body to a latent image portion on the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. An image forming apparatus comprising:
A detection means for detecting image memory, solid followability and image density unevenness, and a control means for controlling the image memory, solid followability and image density unevenness, respectively;
The control means controls the image memory by controlling the amount of toner carried per unit area on the toner carrier, while the peripheral speed of the toner carrier relative to the circumferential speed of the electrostatic latent image carrier. By controlling the development-side peripheral speed ratio, which is the ratio, the solid followability and image density unevenness are controlled,
Further, the control means has a control flow for adjusting solid followability and image density unevenness after first adjusting the image memory.
An image forming apparatus. 6. The control unit according to claim 1, wherein the toner carrying amount per unit area on the toner carrying member is controlled by controlling an average potential difference ΔV _avg of the supply and recovery region. The image forming apparatus according to any one of the above.   The image forming apparatus according to claim 1, wherein the control unit controls the developing-side peripheral speed ratio by controlling a rotation speed of the toner carrier.   In the image adjustment, the control means sets the number of rotations of the toner carrier to the minimum speed in the use range, and then adjusts the solid followability after first adjusting the image memory. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, comprising a plurality of toner carriers. a) a developer carrying member carrying a developer containing a non-magnetic toner and a magnetic carrier; b) an electrostatic latent image facing the developer carrying member through a supply / recovery region and through the developing region. A toner carrier disposed opposite to the carrier and carrying the toner supplied from the developer carrier in the supply and recovery region; and c) developing between the developer carrier and the toner carrier. A first electric field for supplying and collecting toner is formed between the agent carrier and the toner carrier, and the toner carrier is provided between the toner carrier and the electrostatic latent image carrier. An electric field forming means for forming a second electric field for transferring toner from the body to a latent image portion on the electrostatic latent image carrier to visualize the electrostatic latent image as a toner image. An image adjustment method in an image forming apparatus comprising:
Detecting image memory and at least one of solid traceability, gradation reproducibility, fine line reproducibility, graininess, and image density unevenness,
The development side which is the ratio of the peripheral speed of the toner carrier to the peripheral speed of the electrostatic latent image carrier after adjusting the image memory by controlling the amount of toner carried per unit area on the toner carrier By controlling the peripheral speed ratio, image adjustment is performed for at least one of the solid followability, gradation reproducibility, fine line reproducibility, graininess, and image density unevenness.
An image adjustment method in an image forming apparatus. The image forming apparatus according to claim 10, wherein a toner carrying amount per unit area on the toner carrying member is controlled by controlling an average potential difference ΔV _avg of the supply and collection region. Image adjustment method.   12. The image adjustment method for an image forming apparatus according to claim 10, wherein the developing-side peripheral speed ratio is controlled by controlling the rotation speed of the toner carrier.   At the time of image adjustment, the rotation speed of the toner carrier is set to the minimum speed in the usable range, and after first adjusting the image memory, the solid followability, gradation reproducibility, fine line reproducibility, graininess The image adjustment method for an image forming apparatus according to claim 10, wherein image adjustment is performed for at least one of image density unevenness and image density unevenness.   14. The image adjustment method for an image forming apparatus according to claim 10, wherein a plurality of toner carriers are provided.