JP2003005536A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of steadily obtaining a sharp, high quality image by preventing image flow, etc., even in a high humidity environment. SOLUTION: The image forming device has a non-crystalline silicon photoreceptor drum (image carrier) 1, an intermediate transfer body (transfer rotation body) 81, which can be brought into contact with the photoreceptor drum 1, a pressing means for pressing the intermediate transfer body 81 to the photoreceptor drum 1, and a transfer member (transfer means) 4 for transferring a toner image on the photoreceptor drum 1 onto the intermediate transfer body (or a recording material held on the transfer rotation body). In the image forming device, the function of abrading the surface of the photoreceptor drum 1 is provided on the surface of the intermediate transfer body 81.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for transferring a visible image formed on an image carrier to a recording material on a recording material carrier to form an image.

[0002]

2. Description of the Related Art An amorphous silicon (A-Si) type drum used as a photoconductor of an image forming apparatus has high durability and is therefore suitable as a photoconductor of a high speed printer or a high speed copying machine. Also, since it is non-toxic, it is one of the most noticeable photoreceptors from the viewpoint of environmental problems.

FIG. 5 shows a cross section of an image forming apparatus using an amorphous silicon (A-Si) type drum as a photosensitive member. In the main body of the image forming apparatus, an endless recording medium carrying in the direction of arrow X is carried. A body 8 is arranged. The recording material carrier 8 is made of a dielectric resin such as a polyethylene terephthalate resin film or a polyvinylidene fluoride resin film. The recording material 6 taken out from the paper feed cassette 60 is supplied to the recording material carrier 8 via the registration rollers 13 and further conveyed to the left side in FIG.

Further, four image forming portions Pa, Pb, Pc and Pd having basically the same structure are arranged in series above the intermediate transfer member 81 which is a transfer rotating member.

The image forming sections Pa, Pb, Pc and Pd are
The photosensitive drums 1a, 1b, 1c, 1d are provided, and the primary charger 2 is provided on the outer circumference of each of the photosensitive drums 1a, 1b, 1c, 1d.
a, 2b, 2c, 2d, developing units 3a, 3b, 3c, 3
d, transfer members 4a, 4b, 4c, 4d and cleaner 5
a, 5b, 5c, and 5d are provided, and a light source device and a polygon mirror 17 (not shown) are installed above the device. The image forming portion Pa is provided with a rotating cylindrical photosensitive drum 1a, and is provided with image forming means such as a primary charger 2a, a developing device 3a and a cleaner 5a around the photosensitive drum 1a. The developing devices 3a, 3b, 3c and 3d respectively have magenta toner,
It contains cyan toner, yellow toner, and black toner.

Then, the image signal of the magenta component color of the original is projected onto the photosensitive drum 1a via the polygon mirror 17 and the like to form an electrostatic latent image on the photosensitive drum 1a, and this electrostatic latent image is formed. Magenta toner is supplied from the developing device 3a to the electrostatic latent image to be visualized as a magenta toner image. Then, when this magenta toner image arrives at the transfer site where the photosensitive drum 1a and the intermediate transfer body 81 come into contact with each other as the photosensitive drum 1a rotates, the magenta toner image is applied by the first transfer bias applied to the first transfer member 4a. The magenta toner image is transferred to the intermediate transfer body 81.

Intermediate transfer member 8 carrying a magenta toner image
When No. 1 is conveyed to the image forming unit Pb, the cyan toner image formed on the photosensitive drum 1b in the image forming unit Pb by this time by the same method as described above is transferred onto the magenta toner image.

Similarly, the intermediate transfer member 81 is connected to the image forming portion Pc,
As the yellow toner image and the black toner image are superposed and transferred onto the toner images at the respective transfer parts as they progress to Pd, the recording material 6 taken out from the paper feeding cassette 60 reaches the transfer parts by this time. , Transfer member 40
The four color toner images are transferred onto the recording material 6 carried and conveyed on the recording material carrier 8 by the transfer bias applied to the recording material carrier 8.

The residual toner remaining on the photosensitive drums 1a, 1b, 1c, 1d is removed by the cleaners 5a, 5b, 5c, 5d, and the residual charges are removed by the pre-exposure means, so that the photosensitive drums 1a-1d are The image can be formed. Further, a charge eliminator 12 and a cleaning fur brush 16 are disposed at a position downstream of the transfer portion of the intermediate transfer body 81, and these remove the electric charge of the intermediate transfer body 81 and the toner and the like attached thereto. .

The recording material 6 on which the toner images of the respective colors have been transferred is heated and pressed by the fixing device 32 to fix the toner images, and then, as a full-color recording image, a discharge tray outside the device. It is discharged onto 63.

Here, the fixing device 32 includes the fixing roller 5
1, pressure roller 52, heat resistant cleaning members 54 and 55 for cleaning each of fixing roller 51 and pressure roller 52, roller heaters 56 and 57 installed in fixing roller 51 and pressure roller 52, Fixing roller 5
1, a coating roller 50 for coating a release agent oil such as dimethyl silicone oil, an oil reservoir 53, and a pressure roller 5
The thermistor 58, which controls the fixing temperature by detecting the temperature of the surface of the second member 2, and the like.

[0012]

However, in the conventional image forming apparatus, if the heater provided on the amorphous silicon photoconductor is not constantly energized under high humidity, the corona product or the like attached to the surface of the photoconductor is generated. Foreign matter promotes lowering of the resistance of the surface of the photoconductor, resulting in deterioration of image quality such as image deletion. This is because the aim of removing low-resistance substances such as discharge products from the surface of the photoconductor together with the toner by rubbing the surface of the photoconductor with the cleaning device cannot be completely achieved for the following reasons. it is conceivable that.

That is, first of all, in the cleaning device
The rubbing member mainly interposes the transfer residual toner with the photosensitive member.
Although it is rubbing against the photoconductor,
Is the talc contained in the transfer material as a filler (chemical composition:
ug₃ (Si_Four O_Ten) (OH) ₂ ) And other hygroscopic materials
Quality, which may cause the surface of the photoreceptor to be exposed under high humidity.
Area resistance is partially 10¹¹The image flow is reduced to about Ω.
It is conceivable that it is likely to occur.

Secondly, in the transfer residual toner, the ratio of the external additive contained in the toner may be high, which is particularly remarkable when the external additive has a polarity opposite to the charging polarity of the toner. However, in this case, the ratio of the external additive in the cleaning section is also increased and the rubbing force on the photosensitive member is partially reduced, which is considered to cause image deterioration.

Thirdly, a magnet roller is arranged on the upstream side of the cleaning blade, a magnetic brush is formed by a part of the toner collected by the cleaning device, and the magnetic brush is brought into contact with the surface of the photoconductor to re-supply the magnetic toner. However, when various foreign matters adhering to the surface of the photoconductor are scraped off by the abrasive action of the toner particles at the blade portion, it is considered that the abrasive action of the toner particles is not uniform in the longitudinal direction. In particular, the amount of collected toner is small at both ends of the cleaning device, toner cannot be accumulated between the photoconductor and the magnet roller, and the effect of the abrasive effect by the toner particles may not be expected.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent image deletion and the like even in a high humidity environment and to stably obtain a sharp high quality image. An object is to provide an image forming apparatus.

[0017]

In order to achieve the above-mentioned object, the present invention provides an image carrier of an amorphous silicon type, a transfer rotary member capable of contacting the image carrier, and the image carrier. An image forming apparatus comprising: a pressing unit that presses the transfer rotator toward a transfer unit; and a transfer unit that transfers the toner image on the image carrier to a recording material carried on the transfer rotator or on the transfer rotator. The surface of the transfer rotator has a function of polishing the surface of the image carrier.

Therefore, according to the present invention, since the function of polishing the surface of the image carrier is provided on the surface of the transfer rotor, various foreign matters such as talc adhering to the surface of the image carrier can be removed by the transfer rotor. This makes it possible to prevent the occurrence of image deletion or the like even under a high humidity environment and stably obtain a sharp high-quality image.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a sectional view of an image forming apparatus according to the present invention, and FIG. 2 is a sectional view of one image forming portion of the image forming apparatus.

Since the basic structure of the image forming apparatus according to the present invention is similar to that of the conventional image forming apparatus shown in FIG. 5, the same elements as those shown in FIG. 5 are the same in FIGS. 1 and 2. The reference numerals are attached and the description thereof will be omitted below.

In the present embodiment, the photosensitive drums 1a, 1b, 1c on the surface of the intermediate transfer member 81, which is a transfer rotary member,
This is different from the conventional one in that minute irregularities are formed on the surface contacting 1d.

In the present embodiment, the intermediate transfer member 81
, A polyimide resin having a thickness of 100 μm is used, and fine irregularities are formed on the surface by sandblasting. The 10-point average roughness (Rz) of the surface of the intermediate transfer member 81 in the circumferential direction is JIS. According to the measurement method based on the standard (JISB0601-1982), 3.0μ
m.

The unevenness formed on the surface of the intermediate transfer body 81 by the rubbing of the surface of the photosensitive drums 1a to 1d and the intermediate transfer body 81 during the image forming operation is caused by various foreign matters such as talc adhering to the surface of the photosensitive drums 1a to 1d. Remove by rubbing. And
The foreign matter such as talc removed by the unevenness formed on the surface of the intermediate transfer body 81 is held in the concave portion of the surface of the intermediate transfer body 81 and removed by the cleaning member that abuts on the intermediate transfer body 81.

It has been confirmed by experiments that the effect of removing foreign matter by rubbing is enhanced by making the peripheral speeds of the photosensitive drums 1a to 1d different from the peripheral speed of the intermediate transfer member 81. In the image forming apparatus according to (1), the peripheral speeds of the photosensitive drums 1a to 1d are set to 133 [mm / sec] and the peripheral speed of the intermediate transfer member 81 is set to 137 [mm / sec], and the peripheral speed between them is about 3%. The peripheral speed difference is attached.

Further, in the present embodiment, the peripheral speed of the intermediate transfer member 81 is set higher than the peripheral speed of the photosensitive drums 1a to 1d. For example, the peripheral speed of the photosensitive drums 1a to 1d is 137 [. [mm / sec] and the peripheral speed of the intermediate transfer member 81 is 133 [mm / sec], so that the peripheral speed of the intermediate transfer member 81 is set to be slower than the peripheral speed of the photosensitive drums 1a to 1d. The foreign substance removing effect is enhanced, and the same effect is obtained.

Incidentally, the photosensitive drums 1a to 1d and the intermediate transfer member 8
When the peripheral velocities of the photosensitive drums 1 are different, the images formed on the photosensitive drums 1a to 1d expand and contract in the circumferential direction at the time of transfer.
It is necessary to expand and contract the projected image and project it in the step of projecting the electrostatic latent image by projecting onto 1d.

By adopting the structure as described above, it becomes possible to remove various foreign matters such as talc adhering to the surfaces of the photosensitive drums 1a to 1d by the intermediate transfer member 81, and the image can be obtained even in a high humidity environment. It became possible to obtain sharp high-quality images in a stable manner by preventing the occurrence of flow.

It was also confirmed that even in the image forming apparatus adopting the multiple transfer system, the same effect can be obtained by applying the structure according to the present embodiment to the recording material carrier which is the transfer rotary member. .

<Second Embodiment> Next, a second embodiment of the present invention will be described.

Since the basic structure and operation of the image forming apparatus according to the present embodiment are the same as those of the image forming apparatus according to the first embodiment, hereinafter, the same elements as those described in the above embodiment are the same. Description will be given using reference numerals.

In the present embodiment, a portion of the surface of the intermediate transfer member 81 for polishing the surface of the photosensitive drums 1a to 1d is formed in a non-image forming area on the surface of the intermediate transfer member 81, and the intermediate transfer member 81 is connected to the photosensitive drums 1a to 1d. The photosensitive drums 1a to 1d are pressed by pressing means for pressing the intermediate transfer member 81 while contacting the surface of the photosensitive drum 1d.
It is characterized in that the pressure of the intermediate transfer member 81 against the is increased.

FIG. 3 shows a developed view of the intermediate transfer member 81.
In the figure, the shaded area is the area having polishing ability, and this area is the non-image forming area. Further, as in the first embodiment, the surface of the intermediate transfer member 81 is formed with minute irregularities by sandblasting, and the surface of the intermediate transfer member 81 in the circumferential direction has a 10-point average roughness (Rz).
Is a measurement method based on the JIS standard (JISB0601-
According to 1982), it is 3.0 μm. Incidentally, in order to evenly polish the surfaces of the photosensitive drums 1a to 1d, the intermediate transfer member 8
It is preferable to set the circumferential length of the polishing portion of No. 1 to be a multiple of the circumferential length of the photosensitive drums 1a to 1d. However, when the peripheral speeds are made different, it is necessary to set the polishing portion so as to correspond to n rounds (n is an integer) of the photosensitive drums 1a to 1d in consideration of the speed difference.

FIG. 4 shows a cross section in the vicinity of a portion where the surface of the intermediate transfer member 81 of the image forming apparatus according to the present embodiment contacts the photosensitive drum 1 (1a-1d).

The transfer member 4 (4a-4d) is fixed to a base 91, and the base 91 is biased downward by a spring 92. Further, the transfer member 4 is installed so as to face the photosensitive drum 1 via the intermediate transfer body 81, and the transfer member 4 is regulated by the transfer pressure adjusting cam 90 from being biased against the photosensitive drum 1. Here, the transfer pressure adjusting cam 90 is
Two types of pressing can be selected, and in the present embodiment,
A transfer pressure (total pressure) of 800 gf during image formation and a transfer pressure (total pressure) of 1600 gf during polishing can be selected.

The operation of the transfer pressure adjusting cam 90 will be described with reference to FIG. 4. During normal image formation, the transfer pressure adjusting cam 90 is stopped at the position shown by the solid line in the figure. The total pressure of the transfer member 4 against the photosensitive drum 1 at this time is 800 gf.

On the other hand, while the polishing portion of the intermediate transfer member 81 is in contact with the photosensitive drum 1, the transfer pressure adjusting cam 9
0 rotates in the direction of the arrow and stops at the position shown by the chain line in the figure. The total pressure of the transfer member 4 against the photosensitive drum 1 at this time is 1600 gf.

By adopting the above structure, it becomes possible to remove various foreign matters such as talc adhering to the surface of the photosensitive drum 1 by the intermediate transfer member 81.
Even in a high humidity environment, it is possible to prevent sharp images and to stably obtain sharp high quality images.

In the present embodiment, the transfer member 4
Although a blade-shaped conductive member was used as a roller,
Similar effects were obtained by using other shapes. or,
Even when a non-contact type transfer member such as a corona charger is used, the same effect can be obtained by providing another member for urging the transfer rotary member to the photosensitive drum and switching the pressure as in the present embodiment. Was obtained.

Further, it has been confirmed that even in the image forming apparatus adopting the multiple transfer system, the same effect can be obtained by applying the structure according to the present embodiment to the recording material carrier which is the transfer rotary member. .

<Third Embodiment> Next, a third embodiment of the present invention will be described.

Since the basic structure and operation of the image forming apparatus according to the present embodiment are the same as those of the image forming apparatus according to the first embodiment, hereinafter, the same elements as those described in the above embodiment are the same. Description will be given using reference numerals.

In the present embodiment, by applying a higher bias to the transfer member 4 than during normal image formation, while the portion of the surface of the intermediate transfer member 81 for polishing the surface of the photosensitive drum 1 is in contact with the surface of the photosensitive drum 1. It is characterized in that the adhesion of the intermediate transfer member 81 to the photosensitive drum 1 is increased.

In the present embodiment, during normal image formation, the transfer member 4 is optimal for transferring the toner on the photosensitive drum 1 according to the type of the recording material 6 and the use environment (temperature / humidity). A bias is applied according to the value.

On the other hand, while the polishing portion of the intermediate transfer body 81 is in contact with the photosensitive drum 1, in order to enhance the adhesion between the surface of the intermediate transfer body 81 and the photosensitive drum 1, a normal image is formed on the transfer member 4. A higher bias is applied than at times. The bias applied to the transfer member 4 while the polishing portion of the intermediate transfer member 81 is in contact with the photosensitive drum 1 is
Although the upper limit of the voltage that can be applied varies depending on the material of No. 1 and the like, the adhesion between the surface of the intermediate transfer body 81 and the photosensitive drum 1 is improved by applying a higher bias within a range that does not cause dielectric breakdown to the intermediate transfer body 81. Is preferred.

By adopting the above structure, it becomes possible to remove various foreign matters such as talc adhering to the surface of the photosensitive drum 1 by the intermediate transfer member 81.
Even in a high humidity environment, it is possible to prevent the occurrence of image deletion and to stably obtain a sharp high quality image.

In this embodiment, the transfer member 4
Although a blade-shaped conductive member was used as a roller,
Similar effects were obtained by using other shapes. or,
Even when a non-contact type transfer member such as a corona charger is used, the same effect can be obtained by providing another member for urging the transfer rotary member to the photosensitive drum and switching the pressure as in the present embodiment. Was obtained.

Further, it was confirmed that even in the image forming apparatus adopting the multiple transfer system, the same effect can be obtained by applying the structure according to the present embodiment to the recording material carrier which is the transfer rotary member. .

[0049]

As is apparent from the above description, according to the present invention, an amorphous silicon type image bearing member, a transfer rotary member capable of contacting the image bearing member, and the image bearing member are provided. An image forming apparatus comprising: a pressing unit that presses the transfer rotator toward a transfer unit; and a transfer unit that transfers the toner image on the image carrier to a recording material carried on the transfer rotator or on the transfer rotator. Since the surface of the transfer rotator is provided with a function of polishing the surface of the image carrier, various foreign matters such as talc adhering to the surface of the image carrier can be removed by the transfer rotator, and in a high humidity environment. In addition, it is possible to stably obtain a high-quality sharp image by preventing the occurrence of image deletion.

[Brief description of drawings]

FIG. 1 is a sectional view of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing the configuration of one image forming unit of the image forming apparatus according to the present invention.

FIG. 3 is a development view of an intermediate transfer member of the image forming apparatus according to the second and third embodiments of the present invention.

FIG. 4 is a cross-sectional view of the vicinity of a portion where the surface of the intermediate transfer member of the image forming apparatus according to the second and third embodiments of the present invention contacts the photosensitive drum.

FIG. 5 is a sectional view of a conventional image forming apparatus.

[Explanation of symbols]

1 (1a to 1d) Photosensitive drum (image carrier) 4 (4a to 4d) Transfer member (transfer means) 6 recording material 8 Recording material support 81 Intermediate transfer body (transfer rotary body) 90 Transfer pressure adjustment cam 92 Spring (pressing means)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H030 AB02 AD17 BB02 BB23 BB42                       BB44 BB53 BB54                 2H200 FA01 FA08 FA20 GA12 GA18                       GA23 GA34 GA44 GA47 HA02                       HB14 JA02 JA26 JA29 JB06                       JB32 JC04 JC15 JC17 JC19                       LA18 LB02 LB15 MA04 MA13                       MA20 MB01 MC06 MC18 PA03                       PA11 PA14

Claims (11)

[Claims] 1. An amorphous silicon-based image bearing member, a transfer rotator capable of contacting the image bearing member, a pressing unit for pressing the transfer rotator toward the image bearing member, and the image. In an image forming apparatus having a transfer means for transferring a toner image on a carrier to the transfer rotator or a recording material carried on the transfer rotator, the surface of the transfer rotator is ground to the surface of the image carrier. An image forming apparatus having a function. 2. The image forming apparatus according to claim 1, wherein unevenness is formed on at least a part of the surface of the transfer rotator as a function of polishing the surface of the image carrier. 3. The image forming apparatus according to claim 1, wherein polishing particles are embedded in at least a part of the surface of the transfer rotator as a function of polishing the surface of the image carrier. 4. The length of the portion of the surface of the transfer rotator having a function of polishing the surface of the image carrier in the circumferential direction of rotation is set to be at least the peripheral length of the image carrier. The image forming apparatus according to any one of 1 to 3. 5. A portion having a function of polishing the surface of the image bearing member on the surface of the transfer rotator is formed in a portion other than the image forming portion or the recording material holding portion of the surface of the transfer rotator. The image forming apparatus according to any one of 1 to 4. 6. The peripheral velocity of the image carrier is Sd [mm / s
ec], the peripheral speed of the transfer rotary member is St [mm / se
The image forming apparatus according to claim 1, wherein Sd / St ≧ 0.01 in the case of [c]. 7. The peripheral velocity of the image carrier is Sd [mm / s
ec], the peripheral speed of the transfer rotary member is St [mm / se
The image forming apparatus according to claim 1, wherein St / Sd ≧ 0.01 when c]. 8. A method for measuring the roughness of a portion of the surface of the transfer rotator, which polishes the surface of the image carrier, according to JIS standard (JI).
SB0601-1982), Rz ≧ 3.0 [μ
m]. The image forming apparatus according to claim 2, wherein 9. The pressing force of the transfer rotator against the image carrier by the pressing means is increased while a portion of the surface of the transfer rotator for polishing the surface of the image carrier is in contact with the surface of the image carrier. The image forming apparatus according to any one of claims 1 to 8. 10. A bias higher than that during normal image formation is applied to the transfer means while a portion of the surface of the transfer rotator for polishing the surface of the image carrier is in contact with the surface of the image carrier. Item 10. The image forming apparatus according to any one of Items 1 to 9. 11. The image according to claim 2, further comprising means for removing foreign matter attached to a portion of the surface of the transfer rotator having a function of polishing the surface of the image carrier. Forming equipment.