JPH1152707A - Toner carrying roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the property of carrying toner, without using electrostatic force, without causing a deterioration in the toner and the degradation and damage of a member to be abutted and to acquire stable and sufficient toner peeling performance by specifying the relation between the cross-sectional areas in a radial direction of recessing and projecting parts formed on the outer periphery of a foamed elastic body. SOLUTION: A toner carrying roller 6 is constituted in such a manner that a foamed roller 16 surrounds the circumference of a core metal 17 made of metal. The foamed roller 16 has a large number of projecting and recessing parts 21 and 22 uniformly distributed on the surface. Both of the projecting and recessing parts 21 and 22 are alternately formed in parallel with the core metal 17. In such a case, it is constituted so that when the cross-sectional area S1 of the projecting part is of the area of a part surrounded by the ridge of the projecting part and an auxiliary line that links places (inside-diameter parts) smallest in diameter in adjacent recessing parts and the cross-sectional area S2 of the recessing part is of the area of the part surrounded by the ridge of the projecting part forming the recessing part and the auxiliary line that links the apexes (outside diameters) of adjacent projecting parts, the relation of S1<=S2 is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner conveying roller mounted on a developing device, a cleaning device and the like used in an electrophotographic image forming apparatus such as a copying machine and a printer.
In particular, the present invention relates to a toner transport roller having not only a mere toner transport function but also a function of peeling and transporting toner on an abutted member by contact.

[0002]

2. Description of the Related Art A toner conveying roller of this type is used by being brought into contact with another member. For example, when it is brought into contact with a toner carrier (developer carrier) in a developing device, a toner carrier is used. The transfer of the toner to the toner carrier and the peeling of the toner from the toner carrier are performed by the cleaning device.
Each is functionally required. That is, both functions of the toner transport function and the toner peeling function are required.

Conventionally, many proposals have been made using a solid rubber material, a brush material, a foamed rubber material, or the like as a toner conveying roller.

First, focusing on the toner transport function, it is difficult to obtain a sufficient toner transport property because the solid rubber material among these various rollers has a smooth surface. Although the brush body has an excellent toner conveying function, it has problems such as removal and cutting of brush fibers. On the other hand, the foamed rubber material is greatly improved in toner transportability as compared with the solid rubber material due to the foamed holes formed on the surface, and is suitable and widely used as a material for the toner transport roller.

On the other hand, according to Japanese Patent Application Laid-Open No. 2-191974, the foamed rubber material has significantly improved toner transportability compared to the solid rubber material due to the foamed holes formed on the surface.

A toner supply member using the foamed rubber material to further improve the toner conveying force is disclosed in Japanese Patent Laid-Open Publication No. Hei 5-6135.
No. 0 discloses this. The toner supply member supplies the toner from the toner hopper in the toner supply device to the developing device, and makes the surface of the foamed elastic body have an uneven shape. Specifically, the foam body is processed by a hot-wire cutting method, and an uneven shape is formed on the roll surface.
The function is mainly to form a concave portion and take in and transport more toner, and the shape is not particularly limited as long as it is easy to catch and release the toner.

Next, focusing on the toner peeling function, a method in which a foamed elastic roller is brought into contact with a member to be abutted to mechanically peel off the toner is disclosed in Japanese Patent Application Laid-Open No. 2-191974. As described above, there is known a method in which a bias is applied to a foamed elastic roller to peel off toner from an abutted member by electrostatic force.

[0008]

However, in recent years, it is necessary to further reduce the particle size of the toner used in the electrophotographic image forming apparatus in order to further improve the image quality. They tend to be less likely to be peeled off.

In order to cope with this, it is necessary to further improve the stripping performance, and for that purpose, the amount of penetration into the member to be contacted is increased, the contact width (hereinafter referred to as “nip width”) is increased, A method of increasing the mechanical force, such as increasing the number of rotations of the roller, can be considered.

However, in these methods, the stress on the toner and the member to be contacted increases, and poor charging, fusion and solidification due to toner deterioration, deterioration and damage of the member to be contacted, and furthermore, foaming elasticity It causes problems such as damage to the body itself.

When the above-described electrostatic force is used, the foamed elastic roller must be made conductive.
The addition of the conductive material tends to hinder the necessary physical properties of the foamed elastic body. Further, a bias power supply and the like are required, and the configuration is complicated and the cost becomes high.

Accordingly, it is an object of the present invention to provide a stable and sufficient toner while maintaining toner transportability without utilizing electrostatic force, and without causing toner deterioration and deterioration or damage of a member to be contacted. An object of the present invention is to provide a toner conveying roller capable of obtaining peeling performance.

[0013]

The above object is achieved by a toner conveying roller according to the present invention. In summary, the present invention relates to a toner conveying roller having a rotating shaft and a foamed elastic member provided around the rotating shaft, and having a convex portion and a concave portion on the outer peripheral surface of the foamed elastic member. The toner conveying roller is characterized in that S1 ≦ S2, where S1 is the radial cross-sectional area per unit and S2 is the radial cross-sectional area per unit.

According to another aspect of the present invention, a toner transport roller having a rotating shaft and an elastic foam provided around the rotating shaft, and having a concave portion and a convex portion on the outer peripheral surface of the elastic foam member , The length of the outer circumferential surface of the convex portion is b, the distance in the circumferential direction from the circumferential center point of the outer circumferential surface of the convex portion to the circumferential center point of the outer circumferential surface of the adjacent convex portion is d, When the length is c and the circumferential length of the valley portion of the concave portion is f, 2b + c−
A toner transport roller characterized by f ≦ d is provided.

The toner conveying roller is preferably an elastic roller which presses against the developer carrying member of the developing container to supply and peel off the toner to the developer carrying member. According to another aspect, the toner transport roller is a cleaning roller that presses against a latent image carrier that carries a latent image and cleans toner on the latent image carrier.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a toner conveying roller according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 2 shows a developing device provided with the toner conveying roller of the present embodiment.

In FIG. 2, a developing device 4 includes a developing container 14 containing a non-magnetic toner 8 as a one-component developer, and is located at an opening extending in the longitudinal direction in the developing container 14 and faces the photosensitive drum 1. A developing sleeve 5 as a developer carrier provided therein, and develops and visualizes the electrostatic latent image on the photosensitive drum 1.

In the developing device 4, the developing sleeve 5
The right half of the peripheral surface shown in FIG.
, And is laterally provided with a substantially half left peripheral surface exposed outside the developing container 14. The surface exposed to the outside of the developing container 14 faces the photosensitive drum 1 located on the left side of the developing device 4 in FIG. The developing sleeve 5 is driven to rotate in the direction of arrow B, and its surface has appropriate irregularities for increasing the probability of rubbing with the toner 8 and for carrying the toner 8 well.

The irregular surface is subjected to irregular sandblasting with alundum abrasive grains or regular sandblasting with glass beads. Further, in order to form the convex part rough surface, for example, conductive particles such as metal oxide particles, graphite, and carbon, which can form the convex part alone, are used to bind the particles to the concave part formation. The uneven surface may be formed using a resin such as phenol or fluorine.

An elastic blade 7 is provided above the developing sleeve 5 so that the elastic blade 7 is supported by the holding metal plate 15 so that the vicinity of the free end thereof is brought into surface contact with the outer peripheral surface of the developing sleeve 5. The contact direction is a so-called counter direction in which the leading end side with respect to the contact portion is located on the upstream side in the rotation direction of the developing sleeve 5.

The elastic blade 7 is formed of a SUS or phosphor bronze thin metal plate 7a having a spring elasticity for maintaining a pressing force of the elastic blade 7 against the developing sleeve 5 as a rubber material such as urethane rubber or silicone rubber as an elastic body 7b. And various types of elastomers such as nylon, Teflon and the like are provided by bonding or injection molding. In the present embodiment, polyamide and polyether are ester-bonded or amide-bonded in order to impart charging property to the negative toner 8. Phosphor bronze plate 7
The injection molded product was used for a.

The toner conveying roller 6 is in contact with the contact portion of the elastic blade 7 with the surface of the developing sleeve 5 on the upstream side in the rotation direction of the developing sleeve 5 and is rotatably supported.

In the developing device 4 described above, during the developing operation, the toner 8 in the developing container 14 is sent in the direction of the toner conveying roller 6 with the rotation of the stirring member 18 in the direction of arrow C.

Further, the toner 8 is carried to the vicinity of the developing sleeve 5 by the rotation of the toner conveying roller 6 in the direction of arrow D, and is carried on the toner roller 6 at the contact portion between the developing sleeve 5 and the toner conveying roller 6. Toner 8
Are frictionally charged by being rubbed against the developing sleeve 5 and adhere to the developing sleeve 5.

Thereafter, as the developing sleeve 5 rotates in the direction of arrow B, it is fed under pressure of the elastic blade 7, where it is subjected to an appropriate tribo (amount of triboelectric charging) and a thin layer is formed on the developing sleeve 5. Thereafter, the sheet is conveyed to a developing section which is a section facing the photosensitive drum 1.

Undeveloped toner that has not been consumed in the developing section is transferred to the developing sleeve 5 as the developing sleeve 5 rotates.
Collected from the bottom of This collection part has a sealing member 1
9 is provided to allow the undeveloped toner to pass to the developing container 14 and to prevent the toner in the developing container 14 from leaking from the lower portion of the developing sleeve 5.

The collected undeveloped toner on the developing sleeve 5 is peeled off from the surface of the developing sleeve 5 at a contact portion between the toner conveying roller 6 and the developing sleeve 5.
Most of the stripped toner is conveyed along with the rotation of the toner conveying roller 6 and mixes with the toner 8 in the developing container 14 to disperse the charge of the toner. At the same time, new toner is supplied onto the developing sleeve 5 by the rotation of the toner conveying roller 6, and the above-described operation is repeated.

In the developing section, the latent image on the photosensitive drum 1 is transferred between the developing sleeve 5 and the photosensitive drum 1 by a power source 20.
AC voltage (Developing AC bias) with DC superimposed by
Is developed as a toner image.

Next, specific examples of each component in the developing device 4 of this embodiment will be described below.

The developing sleeve 5 is formed by coating a surface of an aluminum sleeve having a diameter of 16 mm with a phenol resin in which carbon is dispersed to a thickness of about 10 μm and having a surface roughness Ra of about 0.9 μm. And the peripheral speed of the photosensitive drum 11 is set to 300 μm.
It was rotated at a peripheral speed of 199 mm / s, which was slightly faster than 7 mm / s.

The toner 8 is a non-magnetic one-component developer,
Those having an average particle size of 6 μm were used.

The elastic blade 7 has a thickness of 1 mm on a metal plate 7 a made of phosphor bronze having a thickness of 0.1 mm and having a spring elasticity.
A molded body of a polyamide elastomer was used as the elastic body 7b so that

Next, the toner conveying roller according to the present invention will be described in detail. As shown in FIG.
Has an outermost diameter of 1 around a metal core 17 having a diameter of 5 mm.
It surrounds the foam roller 16 so as to be 7 mm. The foam roller 16 has a large number of convex portions 21 and concave portions 22 on its surface with a uniform distribution. Both the convex portions 21 and the concave portions 22 are formed in parallel with the cored bar 17 and alternately.

The toner conveying roller 6 is brought into contact with the developing sleeve 5 which is also a member to be contacted, and is further moved in the same direction as the developing sleeve 5 by a driving means (not shown) at a peripheral speed of 158 mm.
/ S.

The foam roller 16 is made of a continuous foaming polyurethane foam, and is preferably an ester polyurethane from the viewpoint of uniform cell size and deformation resistance. As described above, the foam roller 16 has a large number of convex portions 21 and concave portions 22 in a uniform distribution on its surface, and the convex portions 21 and concave portions 22 are parallel to the cored bar 17 over the entire length of the foam portion. And are formed alternately.

Here, the uneven shape of the foam roller 16 will be described in detail.

First, as shown in FIG. 3, the irregular shape is measured by observing the cross section in the radial direction of the foam roller 16 with an optical microscope or the like, taking a photograph or the like, and drawing a schematic line 23 along the ridge line of the uneven portion. Performed by

The cross-sectional area of the convex portion 21 and the concave portion 22 is also obtained by the same method. As shown in FIG. 4, the convex cross-sectional area S1 is the same as the convex ridge line 23a and the portion where the diameter is smallest in the adjacent concave portion. (Hereinafter referred to as “inner diameter portion”) is an area of a portion surrounded by an auxiliary line 23b connecting the two, and the concave cross-sectional area S2 is a convex ridge line 23a forming a concave portion and a vertex of an adjacent convex portion (hereinafter, “ The area is defined by a portion surrounded by an auxiliary line 23c connecting the outside diameter portions.

FIG. 5 is a partial sectional view of the outer peripheral surface of the toner conveying roller in the present embodiment, and FIG. 6 is an enlarged view of FIG.

As shown in FIG. 5, the toner transport roller 6
Outer diameter r ₁ = 17.0 mm, inner diameter r ₂ = 1
6.4 mm. Also, the convex section cross-sectional area S1 shown in FIG.
And the cross-sectional area S2 of the concave portion are substantially the same area as shown in the figure, and are respectively S1 = 0.158 mm ² and S2 = 0.162 mm ² .

The toner conveying roller of this embodiment was mounted on the developing device shown in FIG. 2 and printing operation was performed for 5000 sheets. However, there was no problem on the image, and the toner conveying roller 6 after the printing operation for 5000 sheets was completed. There were no abnormalities such as deformation, loss or breakage.

At this time, at the time of the developing operation, the developing bias applied to the developing sleeve 5 from the power source 20 has a frequency of 2000.
Hz, AC voltage with peak-to-peak voltage of 1600V-
A DC voltage of 400 was superimposed, and the latent image on the photosensitive drum 1 was set to have a surface potential of -600 V in the non-exposed portion and -150 V in the exposed portion, and the exposed portion was subjected to reversal development.

Here, as a comparative example of the toner conveying roller 6 (hereinafter, referred to as a shape A) of the present embodiment, a comparative study was performed with each toner conveying roller shown in FIGS. 7 and 8 made of the same material. .

Incidentally, the sectional area S1 of the convex portion of the toner conveying roller (hereinafter, referred to as shape B) shown in FIG. 7 is 0.150.
mm ^2, recesses sectional area S2 is 0.092Mm ^2, toner conveying roller shown in FIG. 8 (hereinafter, referred to as shape C)
Has a convex sectional area S1 of 0.165 mm ² and a concave sectional area S2
Is 0.314 mm ² .

The evaluation method is as follows.
And installed in a developing device shown in (1) in a low temperature and low humidity environment (15 ° C / 1
A printing operation of 5000 sheets at 0% RH) was performed, and fog, ghost images, and the like were particularly observed and evaluated.

The ghost image is an image as shown in FIG. 9, in which the toner remaining on the developing sleeve 5 in the developing process without being developed is not peeled off by the foamed elastic roller, and the developed pattern (toner) Is a phenomenon that occurs on the image due to the next rotation of the developing sleeve 5, and occurs when the peeling performance is poor. Then, in a low-temperature and low-humidity environment, the toner is easily charged, so that it is difficult for the toner to separate from the developing sleeve due to its mirroring power, so that the ghost image becomes remarkable.

Table 1 below shows the results of the evaluation of each roller.

[0049]

[Table 1]

As described above, the shape A had no problem on the image, and the used roller had no problem.

The shape B had no problem on the image at the initial stage, but fog and ghost image defects occurred after printing 5,000 sheets.

Further observation of the roller after use revealed that some of the convex portions were broken, and that of the non-ruptured convex portions, the toner was dense, that is, hard. When the peeled toner enters the convex part, the toner extruded from the convex part flows smoothly to the following concave part, so that the toner does not stay in the convex part and the peeling performance can be maintained.
In the shape B, although the initial peeling performance can be obtained, since the cross-sectional area S2 of the concave portion, which is the outflow portion of the toner, is smaller than the cross-sectional area S1 of the convex portion, the toner in the convex portion cannot sufficiently flow out and a part of the convex portion cannot be removed. Will remain. Then, if the peeling is continued, the amount of the remaining toner increases, and the density of the convex toner gradually increases, so that the flow of the toner in the convex portion is slowed down.
The scraping performance was poor and a ghost image was generated. In addition, since the convex portions where the toner is in a high density state are hardened, the stress applied to the toner increases, so that the toner is deteriorated, and stable charging of the toner cannot be achieved, and a fog image occurs. Further, the cured projections became brittle mechanically and broke.

On the other hand, in the case of the shape C, as in the case of the shape A, there was no problem on the image, and there was no problem with the used roller. This is because, similarly to the shape A, the toner flows smoothly from the convex portion to the concave portion because the concave portion has a sufficient width contrary to the shape B, so that the peeling performance can be stably maintained. is there.

As described above, in the toner transport roller having a uniform unevenness distribution on the outer periphery of the foam roller,
When the convex section cross-sectional area S1 and the concave section cross-sectional area S2 satisfy the relationship of S1 ≦ S2, stable toner peeling performance and toner transport performance can be obtained.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.

FIGS. 10 and 11 are a partial sectional view and an enlarged view of the outer peripheral surface of the toner conveying roller in the present embodiment, respectively.

In the present embodiment, the toner conveying roller 6 has a substantially trapezoidal shape in which the convex portion 21 becomes smaller toward the outer peripheral side.
1 to improve the stripping performance. Further, when designing the concave and convex shape so as to satisfy the relationship of S1 ≦ S2, the design and production are facilitated by deriving a relational expression of the shape component.

As shown in FIG. 12, similarly to the first embodiment, the radial cross section of the foam roller 16 is observed with an optical microscope or the like, photographed, and the like.
The unevenness was measured by drawing.

FIG. 13 shows each component of the concavo-convex shape based on the schematic line 24. In FIG. 13, b is the upper bottom width of the convex portion, c is the lower bottom width of the convex portion, e is the height of the lower portion of the convex portion, f is the lower bottom width of the concave portion, g is the upper bottom width of the concave portion, and d is the pitch and the interval between the convex portions. It shows the period.

Here, when the convex portion and the concave portion are approximated to a trapezoid, the sectional area S1 of the convex portion is S1 = (1/2) × (b + c) ×
e, the concave cross-sectional area S2 is S2 = (1/2) × (f + g) ×
e. The pitch d is the sum of the area b of the upper bottom of the projection and the width g of the upper bottom of the depression, and d = b + g.

As described in the first embodiment, in order to maintain the stripping performance stably, it is only necessary to satisfy S1 ≦ S2, which is a relation of b + c ≦ f + g. Where d = b
From the relationship + g, 2b + cf ≦ d is derived, and when this relationship is satisfied, the relationship S1 ≦ S2 is also satisfied, and a stable maintenance of the stripping performance is obtained.

In this embodiment, b = 0.33 mm, c
= 0.90 mm, d = 1.34 mm, f = 0.39 m
m and e = 0.26 mm, a toner transport roller having an outer diameter of 17.0 mm was prototyped, mounted on the developing device 4 described in Example 1, and 5,000 prints were performed, but there was no problem on the image. Also, there was no defect in the roller after use.

As described above, stable peeling performance can be obtained by satisfying the relationship of 2b + cf ≦ d in the concavo-convex component. Further, since the shape can be determined without obtaining the respective cross-sectional areas of the convex portion and the concave portion, there is an advantage that the shape design and manufacturing become easy.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 14 shows a cleaning device equipped with the toner conveying roller according to the present embodiment.

In FIG. 14, the developing device 4 shown in FIG. 2 is disposed on the right side of the photosensitive drum 1 in the drawing, and a cleaning device 25 having a cleaning roller 28 as a toner conveying roller is disposed on the left side.

The toner image developed by the developing device 4 is transferred onto a transfer material 31 by a transfer roller 30 to which a bias is applied from a bias power supply (not shown). After the transfer process, the transfer residual toner remaining on the photosensitive drum 1 is removed from the photosensitive drum 1 by the cleaning device 25, and the photosensitive drum 1 is initialized.

Hereinafter, the cleaning device 25 will be described in detail. The cleaning roller 28 comes into contact with the photosensitive drum 1 which is also a member to be contacted, and most of the transfer residual toner is peeled off from the photosensitive drum 1 by the cleaning roller 28 which rotates in the direction of arrow E in FIG. Is completely blocked by the cleaning blade 27.
The cleaning device 2 is provided below the cleaning roller 28.
A squeeze sheet 29 is provided to prevent the toner peeled off from the sheet 5 from leaking out of the apparatus.

The cleaning roller 28 surrounds a metal core 28a of φ5 mm and surrounds the foam roller 28b so that the outermost diameter becomes φ17 mm, and a large number of projections and depressions are uniformly distributed on the surface thereof. ing. The convex portions and the concave portions are formed in parallel with the core metal 28a and alternately over the entire length of the foam portion. Example 1 above
As for the cross-sectional area S1 of the convex portion and the cross-sectional area S2 of the concave portion described above, those having S1 = 0.158 m ² and S2 = 0.162 mm ² were used. Of course, the convex section cross-sectional area S1 and the concave section cross-sectional area S2 described in the first embodiment may be applied.

In the cleaning device provided with the cleaning roller having the above-described structure, more stable cleaning properties can be obtained, the amount of toner conveyed to the cleaning blade 27 is reduced, and the load on the cleaning blade 27 is reduced. There is also an advantage that is extended.

[0070]

As is apparent from the above description, according to the toner conveying roller of the present invention, the concave portion and the convex portion formed on the outer peripheral surface of the foamed elastic body are separated from the radial direction by one convex portion. Assuming that the area is S1 and the radial cross-sectional area per recess is S2, S1 ≦ S2 does not use electrostatic force and causes toner deterioration and deterioration or damage of the member to be contacted. Thus, stable and sufficient toner stripping performance can be obtained while maintaining toner transportability.

The concave and convex portions formed on the outer peripheral surface of the foamed elastic body have a length b of the outer peripheral surface of the convex portion, and a circumferential direction of the outer peripheral surface of the adjacent convex portion from the circumferential center point of the outer peripheral surface of the convex portion. The distance in the circumferential direction to the center point is d, the circumferential length of the root of the protrusion is c,
When the circumferential length of the valley portion of the concave portion is f, 2b + c
By setting −f ≦ d, the same effect as described above can be obtained, and the shape design and manufacturing can be facilitated.

[Brief description of the drawings]

FIG. 1 is a perspective view of a toner conveying roller according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a developing device according to a first exemplary embodiment.

FIG. 3 is an enlarged view of an outer peripheral portion of the toner conveying roller according to the first exemplary embodiment.

FIG. 4 is a schematic diagram of an outer peripheral portion of the toner conveying roller according to the first exemplary embodiment.

FIG. 5 is a partial sectional view of an outer peripheral portion of the toner conveying roller.

FIG. 6 is an enlarged view of the toner conveying roller of FIG.

FIG. 7 is an enlarged view of an outer peripheral portion of Comparative Example 1 used in an experiment of Example 1.

FIG. 8 is an enlarged view of an outer peripheral portion of Comparative Example 2 used in the experiment of Example 1.

FIG. 9 is an explanatory diagram illustrating an example of a ghost image.

FIG. 10 is a sectional view of an outer peripheral portion of a toner conveying roller according to a second embodiment.

FIG. 11 is an enlarged view of the toner conveying roller of FIG.

FIG. 12 is a schematic diagram of an outer peripheral portion of a toner conveying roller according to a second embodiment.

FIG. 13 is an explanatory diagram for defining the length of each portion of the uneven portion of the toner conveying roller according to the second embodiment.

FIG. 14 is a schematic configuration diagram illustrating a cleaning device according to a third embodiment.

[Explanation of symbols]

Reference Signs List 1 photosensitive drum (latent image carrier / contact member) 5 developing sleeve (developer carrier / contact member) 6 toner transport roller 14 developing container 16 foam roller (elastic foam) 17 core metal (rotating shaft) 21 convex part 22 concave part 28 cleaning roller (toner conveyance roller)

Claims (4)

[Claims] 1. A toner conveying roller having a rotating shaft and a foamed elastic body provided around the rotating shaft, and having a convex portion and a concave portion on the outer peripheral surface of the foamed elastic material, S1 ≦ S2, where S1 is the radial sectional area and S2 is the radial sectional area per recess. 2. A toner conveying roller having a rotating shaft and a foamed elastic body provided around the rotating shaft, wherein the outer peripheral surface of the foamed elastic body has a concave portion and a convex portion, B, the distance in the circumferential direction from the circumferential center point of the outer peripheral surface of the convex portion to the circumferential center point of the outer peripheral surface of the adjacent convex portion, d the circumferential length of the root portion of the convex portion, and the valley of the concave portion. A toner conveying roller wherein 2b + cf ≦ d, where f is the circumferential length of the portion. 3. The toner conveying roller according to claim 1, wherein the toner conveying roller is an elastic roller which presses against a developer carrier of the developing device to supply and peel off the toner to the developer carrier. No. 2 toner transport roller. 4. The toner as claimed in claim 1, wherein the toner conveying roller is a cleaning roller that presses against a latent image carrier that carries the latent image and cleans toner on the latent image carrier. Transport rollers.