JP2001034058A - Image forming method and image forming device using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming method capable of preventing the increase of a cost and also suppressing the occurrence of irregularities in an image by setting the dimensional accuracy of a developer carrier which comes into contact with a latent image carrier based on a new stipulation. SOLUTION: As for the image forming method for forming an electrostatic latent image on a previously, uniformly and electrostatically charged latent image carrier 1 by optical writing, bringing a developer carrier 4A with one-component developer on the surface into contact with the latent image carrier 1 while controlling the contact pressure so as to visualize the electrostatic latent image, then, executing a process of transferring/fixing the visible image to a transfer paper, the developer carrier 4A is constituted of a cylindrical member, and provided that a straight line is drawn between two optional points on ridge lines on the optional cross section passing the axial center of the developer carrier, and provided that the maximum distance between the two points on the ridge lines in the normal direction is expressed by T and the moving amount of the developer carrier 4A when the contact pressure is applied on the carrier 4A which is placed on one side between two points and which lies in a contact state on the counter ridge line side with no load is expressed by L, the relation of T<L is set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming method and an image forming apparatus using the same.
The present invention relates to visible image processing of an electrostatic latent image on a latent image carrier.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer, a copying machine or a facsimile machine, an electrostatic latent image formed on a latent image carrier such as a photosensitive drum is made visible by a developer supplied from a developing device. Image processing is performed, and the visible image is electrostatically transferred to a transfer material such as recording paper to obtain a copy.
One of the developers used to process an electrostatic latent image on a latent image carrier into a visible image is a magnetic or non-magnetic one-component developer. In the developing method in which a one-component developer is used,
There is a method using a developer carrying member made of an elastic developing roller which comes into contact with a latent image carrying member with a thinned developer layer carried on the surface. In the above-mentioned developing method, for example, the contact pressure between the two members and the linear velocity ratio of the developer carrier to the latent image carrier are increased to prevent the developer scattering phenomenon and to improve the dot reproducibility. Can be.

However, such a system is susceptible to minute vibrations on the latent image carrier and the developer carrier. For example, when the contact pressure is increased, the load on the driving means for setting the contact pressure is increased. Therefore, there is a problem that an abnormal image due to rotation unevenness called banding is easily generated.

Conventionally, as one of the methods for preventing the above-mentioned burden on the driving means from increasing, there is a method of reducing the contact pressure of the developer carrier with respect to the latent image carrier.
In this method, since the contact pressure at the central portion in the axial direction of the developer carrying member is smaller than that at both ends in the axial direction, there is a possibility that so-called image omission at the central portion may easily occur.

In view of the above, a configuration has been proposed in which the shape of the developer carrying member in the axial direction is such that a central portion in the axial direction is bulged as compared with both ends in the axial direction (see, for example, Japanese Patent Application Laid-Open No. 10-1998).
No. 20657).

[0006]

The developer carrier used for visible image processing is made of an elastic material as disclosed in the above publication. For this reason, a rubber material is generally often used as the elastic body. Rubber is harder to obtain dimensional accuracy than metal, and it is difficult to obtain dimensional accuracy particularly when the hardness is low because polishing is difficult. For this reason, when trying to reduce the contact pressure between the latent image carrier and the developer carrier in order to reduce the load on the driving unit, the contact state between the two tends to be non-uniform, and unevenness on the image may occur. Since this becomes remarkable, it is necessary to strictly control the dimensional accuracy of the developer carrier. The target of the dimensional accuracy includes an outer diameter tolerance, a touch, a cylindricity, and the like, and these parameters are respectively defined.

However, even when the accuracy of each of these parameters is controlled, it may be difficult to improve the occurrence of image unevenness depending on the installation conditions of the developer carrying member. The cost increase due to is undeniable.

An object of the present invention is to solve the above-mentioned conventional image forming method and problems in an image forming apparatus using the same.
In view of the problem in the developer carrier used for the visible image processing of the electrostatic latent image, setting the dimensional accuracy of the developer carrier in contact with the latent image carrier based on a new rule causes an increase in cost. An object of the present invention is to provide an image forming method capable of suppressing the occurrence of image unevenness without using the same, and an image forming apparatus using the same.

[0009]

According to the first aspect of the present invention,
An electrostatic latent image is formed by light writing on a latent image carrier that has been uniformly charged in advance, and the developer carrier having a one-component developer carried on its surface is brought into contact with the latent image carrier by a contact pressure. In the image forming method of performing the visible image processing of the electrostatic latent image by contacting with the supervising, and performing the step of transferring and fixing the visible image to transfer paper, the developer carrying member is configured by a cylindrical member, Any two points on the ridge line are connected by a straight line at an arbitrary cross section passing through the axis of the developer carrier, and the maximum distance in the normal direction of the ridge line sandwiched between the straight line and the two points is T, When the amount of movement of the developer carrier when the contact pressure is applied from a state in which the developer carrier positioned at one of the two points is brought into contact with the opposite ridge line side with no load is L, <L 2.

According to a second aspect of the present invention, one of the ridge lines between the two points corresponds to a part of the peripheral surface of the developer carrying member, and the other of the ridge line between the two points corresponds to the developer carrying member. It is characterized in that it corresponds to a part of the peripheral surface of the opposing latent image carrier.

According to a third aspect of the present invention, the maximum distance T between the normals of the ridge lines sandwiched between the two points corresponds to the distance between the peripheral surfaces of the latent image carrier and the developing carrier. It is characterized by having.

According to a fourth aspect of the present invention, the surface hardness of the developer carrying member is set to 40 ° (JIS-A) or less.

The invention according to claim 5 is characterized in that the developer carrier has a configuration in which both ends in the axial direction are chamfered.

According to a sixth aspect of the present invention, there is provided an image forming apparatus using the image forming method according to any one of the first to fifth aspects, wherein at least both ends of the developer carrier in the axial direction have the latent image. The image forming apparatus is characterized in that it has a configuration in which pressure is applied to the image carrier.

According to a seventh aspect of the present invention, the peripheral surface of the developer carrier is parallel to that of the latent image carrier when the developer carrier is moved by being urged toward the latent image carrier. It is characterized by being supported as follows.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a schematic diagram for explaining an image forming apparatus using an image forming method according to an embodiment of the present invention. In FIG. 1, the image forming apparatus includes a photosensitive member 1 serving as a latent image carrier. As the photoconductor 1, inorganic and organic photoconductors configured in a drum shape are used, and are rotated in the illustrated arrow direction by a driving source (not illustrated).

Around the photosensitive drum 1, a charging device 2 for executing an image forming process along a rotation direction, an optical writing device (only an optical path is shown in the figure) 3,
The developing device 4, the transfer device 5, and the cleaning device 6 are arranged respectively. The surface of the photosensitive drum 1 is uniformly charged by the charging device 2 in the course of rotation, and then an exposure corresponding to an image is performed by the optical writing device 3 to form an electrostatic latent image on the photosensitive layer. Is done.

The electrostatic latent image is subjected to visible image processing by a developer supplied from the developing device 4 at a position facing the developing device 4 (a position indicated by reference numeral P1 in FIG. 1), and the visible image is transferred. At a position facing the device 5 (a position indicated by reference numeral P2 in FIG. 1), the transfer fed from a paper feeding device (only a registration roller which is one component of the paper feeding device is shown in the drawing) 7 The image is transferred to the paper S.

After the transfer, the photosensitive drum 1 is cleaned by a cleaning device 6 to remove the residual developer, and is discharged by a discharging device (not shown).
Is newly charged by being opposed to the image forming apparatus, and is prepared for the next image forming process. The transfer sheet S has an image fixed by a fixing device (not shown) and is discharged to a discharge tray (not shown).

In the present embodiment, a one-component developer is used as a developer used for visible image processing of an electrostatic latent image in the developing device 4, and the structure thereof is as follows. That is,
As a one-component developer, polyester, polyol,
Charge control agent (CCA) for resin such as styrene acrylic,
A toner is used in which a colorant is mixed and a substance such as silica or titanium oxide is externally added around the colorant. The average particle size of the toner is selected from 3 to 12 μm.
7.5 μm is used. This particle size is a value that can satisfy the demand for high resolution, and furthermore, it is sufficiently possible to reduce the particle size further with the demand for high resolution.

The developing device 4 for processing the electrostatic latent image into a visible image uses a contact one-component developing system in which a developing roller 4A, which is a developer carrier, is brought into contact with the photosensitive drum 1 using the toner. In the developing tank 4B, a developing roller 4A facing the photosensitive drum 1, a supply roller 4C facing the developing roller 4A, a stirring device 4D located near the supply roller 4C, and a developing roller 4A are provided. And a regulating blade 4 </ b> E in contact with the main part.

The developing roller 4A is a roller made of a rubber material and having an outer diameter of 10 to 30 mm. Examples of the rubber material include silicone rubber, butadiene rubber, nitrile-butadiene rubber (NBR), hydrin, EPDM
Etc. Further, the surface of the developing roller 4A can be coated with a coating material in order to stabilize the aging quality, and in this case, a silicon-based or Teflon-based material is used. The former material has good chargeability of the toner, and the latter material has excellent releasability.
Furthermore, it is also possible to contain a conductive material such as carbon black in order to improve conductivity, and the thickness of the coating layer is set to 5 to 50 μm. Is preferred. In this embodiment,
Although the hardness of the developing roller 4A is lower than the hardness of the photoconductor drum 1, it is also possible to set a case where the hardness of the developing roller 4A is high and the hardness of the photoconductor side is low.

The supply roller 4C is made of a flexible material such as foamed polyurethane and has a cell having a diameter of 50 to 500 μm and is configured to easily hold the toner on the surface. Further, the surface hardness is set to a relatively low hardness of 10 to 30 ° (JIS-A) so that the surface can be uniformly contacted with the developing roller 4A, and the amount of biting into the developing roller 4A is 0.5 to 1.
It is set to 5 mm. The supply roller 4C is configured to rotate in the same direction as the developing roller 4A, and the linear velocity ratio between the supply roller 4C and the developing roller 4A is in the range of 0.5 to 1.5, and in this embodiment, 0.9. The developing roller 2B
(The direction in which the facing surface moves in the opposite direction).

In the case of the present embodiment, the bite amount is 240 mm, which is equivalent to the width of the unit that can be developed by the developing device 4 when the A4 size transfer paper is fed in the vertical direction.
1.5 to 2.5, which is the required torque for
kg · fcm is obtained. It is possible to set an optimum condition in a wider range because the amount of bite depends on the characteristics of a motor and a gear head included in the drive system of the developing device 4 and the charging characteristics and supply of toner.

The toner carried or present on the surface of the supply roller 4C is induced by triboelectric charging between the two members moving in opposite directions at the point of contact with the developing roller 4A, and the electric charge is induced. In the case of the embodiment, a negative charge is induced by the characteristics of the toner to be used, and the toner is held on the surface of the developing roller 4A by a transport effect due to the surface roughness of the developing roller 4A.

When the developer layer is transferred from the supply roller 4C to the developing roller 4A, the layer of the developer does not have a uniform thickness but is in an excessively adhered state (1 to 3 mg / cm ² ). The thickness is made uniform. The regulating blade 4E has a base extending from a base end supported by the developing tank 4B and a base corresponding to a middle of the developing roller 4A reaching the front end in a state of being directed downstream with respect to the rotation direction (the arrow direction in the drawing) of the developing roller 4A. The edge is brought into contact with the peripheral surface of the developing roller 4A, that is, a so-called counter-type contacting state,
It is composed of a metal blade such as SUS304 having a thickness of 0.1 to 0.15 (mm). In this case, the distance from the contact position with the developing roller 4A to the tip (projection amount)
Is set to 0.1 to 2.0 mm.

As the material of the regulating blade 4E, a rubber material such as polyurethane rubber having a thickness of about 1 to 2 mm, a silicone resin, or a fluorine-based material having the opposite charging property (for example, ETFE, PTFE, P
A resin material having relatively high hardness such as VdF) resin can be used. Since resistance can be reduced by mixing carbon black or the like other than metal, it is also possible to connect a bias power supply to form an electric field between the developing roller 2B.

Further, the free end length of the regulating blade 4E from the base end to the front end is preferably 8 to 15 mm. This is because when the free end length exceeds the upper limit of the above range, the developing device 2
If the size of the developing roller 4A is smaller than the lower limit, vibrations are likely to occur when it comes into contact with the surface of the developing roller 4A. This is based on the fact that an abnormal image such as an image easily occurs.

The regulating blade 4E has a contact pressure against the developing roller 4A of 1 to 25 (g · f / cm), scrapes off uncharged toner on the developing roller 4A, and can form a uniform thin toner layer. It has become. When the contact pressure exceeds the upper limit, the toner adhesion amount on the developing roller 4A decreases, and the toner charge amount increases too much. Therefore, the image density decreases due to the decrease in the development amount due to insufficient transfer of the toner. . Conversely, if the value is below the lower limit, the toner thin layer may not be formed uniformly, and the toner may pass through the regulating blade 4E, and the image quality is significantly reduced.

In this embodiment, the hardness of the developing roller 4A is 4
0 mm (JIS-A) and 0.1mm S
US is used, and 6 (g · f / cm) is selected as the contact pressure. As a result, the excessive toner carried on the developing roller 4A by the regulating blade 4E is scraped off to form a thin toner layer having a uniform thickness, and the charge amount of the toner is reduced to -5 to -30 μC / g. After being set, it is supplied to the electrostatic latent image on the photosensitive drum 1.

The photosensitive drum 1 and the developing roller 4A are in contact with each other via a toner layer carried on the surface of the developing roller 4A. The developing roller 4A can rotate by receiving a driving force from a driving source via a gear (not shown), and the following relationship is set between the developing roller 4A and the photosensitive drum 1. That is, FIG. 2 is a schematic diagram showing a contact state when the developing roller 4A is abutted against the photosensitive drum 1 with a load of 0 g / mm. In FIG. 2, a contact pressure is applied to the developing roller 4A. Let L be the amount by which the developing roller 4A moves when pressed against the photosensitive drum 1, and any two points on the ridge line between the photosensitive drum 1 and the developing roller 4A corresponding to the peripheral surfaces of these members. And the maximum distance in the normal direction of a ridge line sandwiched between the straight line and the two points, that is, the distance in the diameter direction at the relative position between the photosensitive drum 1 and the developing roller 4A in FIG. When T is set, a relationship of T <L is set. FIG. 2 (A)
Indicates that the developing roller 4A is loaded on the photosensitive drum 1 with a load of 0 g.
2 / mm, and FIG.
4B shows a state in which the developing roller 4A is pressed against the photosensitive drum 1 using the pressure F.

The reason is as follows. That is, T
> L, the photosensitive drum 1 and the developing roller 4A
A gap is generated between the peripheral surfaces of the image and the image. In order to avoid this, the shape of the developing roller 4A is defined so as to reduce the above-mentioned T, and the developing roller 4A is pressed against the photosensitive drum 1 until the gap disappears, thereby securing the biting amount. It is necessary.

However, when the gap is eliminated, the pressure applied to eliminate the gap causes the contact pressure to be non-uniform in the axial direction, and not only the image becomes non-uniform, but also excessive drive torque. Required. For example, assuming that the movement amount (L) is 0.05 mm, the outer diameter tolerance is ±
It is conceivable to set the contact state appropriately at 0.05. The outer diameter shape of the developing roller 4A based on such conditions becomes the shape shown in FIG. With this shape, even when a desired movement amount (L) is secured, a gap is generated, and a uniform image cannot be obtained. As described above, in the conventional configuration, since the uniformity of the image cannot be obtained only by the outer diameter dimension,
In addition to the outer diameter tolerance, it is necessary to define the runout and cylindricity.

On the other hand, in the present embodiment, the maximum distance (T) in the diametric direction at the relative position is set so as to be smaller than the movement amount (L). T = 0.05 mm or less, and as a result, no gap is generated. That is, in the relationship according to the present embodiment, as shown in FIGS. 4 and 5, a state is obtained in which the peripheral surface of the developing roller 4A abuts on the photosensitive drum 1 in parallel with the photosensitive drum 1 without any gap. Even if the run-out or cylindricity deviates from the specified values, no gap is generated.

In particular, in the present embodiment, as shown in FIG. 6, the supporting portion of the developing roller 4A is formed by using elastic bodies 50 at a plurality of positions including the end portions in the axial direction, as shown in FIG. Is made parallel to the peripheral surface of the photosensitive drum 1. That is, the bearing portion through which the rotating shaft of the developing roller 4A is inserted is supported so as to be displaceable in a direction perpendicular to the peripheral surface of the photosensitive drum 1, and each end in the axial direction is independently displaceable in that direction. Has become. This allows
When the developing roller 4A is moved toward the photosensitive drum 1 by the moving amount (L) described above, the developing roller 4A is moved so that the peripheral surface of the photosensitive drum 1 and the peripheral surface of the developing roller 4A are parallel.
A is set in the attitude so that no gap is created between them. Therefore, the photosensitive drum 1 and the developing roller 4A come into uniform contact without strictly controlling the runout and the cylindricity. In this case, rubber or a spring material is used as the elastic body 50.

Since the present embodiment has the above configuration,
The distance between the peripheral surface of the developing roller 4A with respect to the photosensitive drum 1 and the amount of movement of the developing roller 4A with respect to the photosensitive drum 1 can be related without strictly defining the outer diameter, runout, and cylindricity of the developing roller 4A. A uniform contact between the two can be made possible only by this.

On the other hand, the contact property of the developing roller 4A with the photosensitive drum 1 is also determined by the surface hardness of the developing roller 4A. This will be described below. If the contact pressure of the developing roller 4A with respect to the photosensitive drum 1 is too weak, the effect of scraping off the residual toner on the photosensitive drum 1 will be reduced, and if the contact pressure is too strong, the driving torque will increase, resulting in missing dots in a halftone image. The adverse effect of this occurs.

Therefore, in the present embodiment, the contact pressure (contact pressure) of the developing roller 4A with respect to the photosensitive drum 1 is 2 to 8 g.
/ Mm. The reason is as follows. FIG.
Is a diagram for explaining the relationship between the surface hardness of the developing roller 4A and the amount of bite. In FIG. 3, the distance (T) between the peripheral surface between the photosensitive drum 1 and the developing roller 4A is set to 0.1. It is understood that when trying to obtain 05 mm, the hardness at which the above contact pressure (contact pressure) can be obtained is 40 °. Therefore, the distance (T) is set to 0.
Given that it is difficult to set the thickness to be less than 05 mm, it is difficult to process. Given that the contact pressure (contact pressure) is 7 g / mm when the bite amount is 0.05 mm, the hardness is set to an upper limit of 40 °. In order to prevent an increase in machining cost when setting the gap accuracy of the above.

In the above configuration, by setting the hardness of the developing roller 4A from which the contact pressure is obtained when the bite amount corresponding to the moving amount of the developing roller 4A is set,
It is possible to prevent an increase in processing cost when setting a gap related to the bite amount.

On the other hand, when the hardness of the developing roller 4A is high, the surface can be polished after molding to a specified size. Therefore, the above-mentioned distance (T) can be obtained by the polishing operation. It becomes difficult. For this reason, it often remains molded according to the mold dimensions at the time of vulcanization molding. However, at the time of molding, the outer diameter in the vicinity of both ends in the axial direction tends to increase depending on conditions such as the cooling rate, and as a result, the shape tends to be as shown in FIG.

Therefore, in the present embodiment, the screen is taken at both ends in the axial direction. In other words, chamfering makes it easier to set the outer diameter dimension at the axial center, in other words, the distance (T) between the outer peripheral surface of the photosensitive drum 1 and the outer diameter.
In addition, a seal member for preventing toner scattering may be pressed against both ends in the axial direction. In this case, if the chamfering is not performed, the surface layer of the developing roller 4A may be peeled off due to abrasion. It can also be prevented. Since such a peeling phenomenon may reach not only an end portion but also an image forming area, it is preferable to perform chamfering in order to prevent such a phenomenon.

[0042]

According to the first to third aspects of the present invention, 2
The maximum distance T between the latent image carrier corresponding to the ridge line between the points and the developer carrier, and the state in which the developer carrier is brought into contact with the latent image carrier opposite thereto with no load. By setting the relationship with the moving amount L when the contact pressure is applied to T <L, the moving distance larger than the maximum distance between the two points is set to cancel the maximum distance and the development on the latent image carrier is performed. Uniform contact of the agent carrier becomes possible. As a result, the contact state when the contact pressure is reduced can be guaranteed without strictly controlling the outer diameter tolerance, runout, and cylindricity of the developer carrier, and the surface is polished at a lower altitude than metal. Even when an elastic body such as rubber, which is difficult to use, is used as the developer carrying member, good contact can be achieved without increasing the cost required for processing, and the occurrence of image unevenness can be prevented.

According to the fourth aspect of the present invention, by defining the surface hardness of the developer carrying member in addition to the above relationship,
Even when the contact pressure of the developer carrier with respect to the latent image carrier is reduced, a uniform contact state can be obtained, thereby preventing occurrence of abnormal images such as image unevenness.

According to the fifth aspect of the present invention, when an elastic body having a higher degree than metal is used as the developer carrying member, both ends in the axial direction are chamfered to satisfy the relationship specified in the first aspect of the present invention. Thus, it is possible to easily obtain an abnormal image without increasing the processing cost.

According to the sixth and seventh aspects of the present invention, even when the contact state between the developer carrier and the latent image carrier becomes non-uniform due to an error in the installation portion of the developer carrier, the developer can be used. The carrier can be installed in a state of being parallel to the peripheral surface of the latent image carrier, and even if the amount of movement of the latent image carrier is set to the above relationship under the installation conditions, uniform contact between the two can be guaranteed. Become. In particular, according to the invention described in claim 7, when another member is in contact with the axial end portion, the surface layer portion can be prevented from being peeled off by the contact member. Since the surface characteristics of the developer are not deteriorated, the supply state of the developer is not changed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a configuration of an image forming apparatus using an image forming method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a contact relationship between a latent image carrier and a developer carrier in an image forming method according to an embodiment of the present invention. The contact state when the roller 4A is abutted with a load of 0 g / mm is
4B shows a state in which the developing roller 4A is pressed against the photosensitive drum 1 using the pressure F.

FIG. 3 is a schematic diagram for explaining one of parameters in a relationship used in the image forming method according to the embodiment of the present invention.

FIG. 4 is a schematic diagram for explaining one contact state between a latent image carrier and a developer carrier obtained by a relationship applied in the image forming method according to the embodiment of the present invention.

FIG. 5 is a schematic diagram for explaining another state of contact between the latent image carrier and the developer carrier obtained by the relationship applied in the image forming method according to the embodiment of the present invention.

FIG. 6 is a schematic diagram for explaining a main configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating characteristics of a developer carrier used in the image forming method according to the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 photosensitive drum as latent image carrier 4 developing device 4A developing roller 4C as developer carrier 4C supply roller corresponding to developer supply member to developer carrier 4E regulating blade T as developer regulating means T photoconductor Maximum distance in the diametrical direction between the peripheral surface of the drum and the peripheral surface of the developing roller L The amount of movement of the developing roller with respect to the photosensitive drum

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Hojima 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H077 AC04 AD06 AD13 AD17 AE04 BA03 EA15 FA13 FA22

Claims (7)

[Claims] An electrostatic latent image is formed by light writing on a latent image carrier uniformly charged in advance, and a developer carrier having a one-component developer carried on its surface is placed on the latent image carrier. An image forming method for performing a visible image processing of the electrostatic latent image by contacting and controlling the contact pressure to transfer and fix the visible image to transfer paper. Any two points on the ridge line are connected by a straight line at an arbitrary cross section passing through the axis of the developer carrier, and the maximum distance in the normal direction of the ridge line sandwiched between the straight line and the two points Is T, and the amount of movement of the developer carrying member when a contact pressure is applied from a state in which the developer carrying member located at one of the two points is brought into contact with the opposite ridge line side with no load is L. An image forming method, wherein the relation of T <L is set. 2. A latent image carrier in which one of the ridge lines between the two points corresponds to a part of the peripheral surface of the developer carrier, and the other of the ridge line between the two points faces the developer carrier. 2. The image forming method according to claim 1, wherein the image forming method corresponds to a part of the peripheral surface. 3. The method according to claim 1, wherein a maximum distance T between a normal line of the ridge line sandwiched between the two points corresponds to a distance between opposing peripheral surfaces of the latent image carrier and the developing carrier. The image forming method according to claim 1. 4. The developer carrier having a surface hardness of 40 ° (J)
IS-A) The following is set:
4. The image forming method according to any one of Items 1 to 3. 5. The image forming method according to claim 1, wherein the developer carrier has a configuration in which both ends in the axial direction are chamfered. 6. An image forming apparatus using the image forming method according to claim 1, wherein at least both ends in the axial direction of the developer carrier face the latent image carrier. An image forming apparatus having a configuration in which pressure is applied. 7. The developer carrier is supported such that the peripheral surface thereof is parallel to that of the latent image carrier when the developer carrier is moved by being urged toward the latent image carrier. The image forming apparatus according to claim 6, wherein: