JP2001042737A - Image forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To minimize contamination inside a machine due to toner. SOLUTION: The toner remaining on the image carrier after the toner image on the image carrier is transferred is brought into contact with the surface 11 of the image carrier 10 which is a rotating body carrying the toner image. Upper edge 2 of tip surface 21c of cleaning blade 21
1a contacts the surface of the image carrier. A deposition member 23b is provided for depositing the toner T scraped off by the blade at least to a position where the upper surface T1 is in contact with the lower edge 21b of the blade tip surface.

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 such as a printer, a facsimile, a copying machine, etc., for forming an image by using an electrophotographic technique. In particular, the present invention relates to a cleaning device using a cleaning blade (hereinafter, simply referred to as a blade) for removing residual toner on an image carrier that carries the toner image.

[0002]

2. Description of the Related Art Generally, an image forming apparatus using an electrophotographic technique has a photosensitive member (an example of an image carrier) having a photosensitive layer on an outer peripheral surface, and a charging means for uniformly charging the outer peripheral surface of the photosensitive member. Exposure means for selectively exposing the outer peripheral surface uniformly charged by the charging means to form an electrostatic latent image; and toner as a developer on the electrostatic latent image formed by the exposure means Developing means for giving a visible image (toner image) by applying
Transfer means for transferring the toner image developed by the developing means onto a transfer medium such as paper; and contacting the surface of the photoreceptor to scrape off toner (residual toner) remaining on the outer peripheral surface of the photoreceptor after transfer. A cleaning device using a cleaning blade for removing and removing the cleaning blade.

Further, as a transfer means, in order to transfer the toner image on the photoconductor to a recording medium such as paper, the toner image formed on the photoconductor is transferred (primary transfer) and carried thereon. There is known an image forming apparatus provided with an intermediate transfer member (an example of an image carrier) that further transfers (secondarily transfers) the toner image to a recording medium. This intermediate transfer member is also provided with a cleaning blade for scraping off and removing toner (residual toner) remaining on the surface after the transfer of the toner image.

[0004]

Generally, toner scraped off by a cleaning blade is scattered in the form of mist (powder cloud). For this reason, the conventional apparatus has a problem that the inside of the apparatus is contaminated by the mist toner. Even if the cleaning blade is provided in the case of the cleaning device, there is a problem that the toner in the form of mist leaks from the gap between the case and the image carrier, and the inside of the device is also contaminated. there were. SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which solves the above-mentioned problems and minimizes the contamination of the apparatus by toner.

[0005]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: an image carrier which is a rotating body for carrying a toner image; A cleaning blade for scraping off the toner remaining on the image carrier after the toner image on the image carrier is transferred, wherein the upper edge of the tip surface of the cleaning blade contacts the surface of the image carrier. An image forming apparatus, further comprising a deposition member that deposits toner scraped by the cleaning blade to at least a position where an upper surface of the toner is in contact with a lower edge of the distal end surface of the cleaning blade. I do. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the image forming apparatus contacts the image carrier below a contact portion between the image carrier and the cleaning blade and is scraped off by the cleaning blade. A rake sheet for toner is provided, and the stacking member is provided integrally with the rake sheet.

[0006]

According to the image forming apparatus of the first aspect, the toner remaining on the image carrier after the transfer of the toner image on the image carrier, which is a rotating body for carrying the toner image, is performed by the image forming apparatus. It is scraped off and removed by a cleaning blade that contacts the surface of the carrier. Since the upper edge of the cleaning blade comes in contact with the surface of the image carrier, the residual toner is scraped off by the upper edge.
According to the image forming apparatus of the first aspect, the deposition member that deposits the toner scraped by the cleaning blade to at least a position where the upper surface of the toner is in contact with the lower edge of the distal end surface of the cleaning blade is provided. As a result, the upper surface of the toner deposited to a position in contact with the lower edge of the front end surface of the cleaning blade by this deposition member, the front end surface of the cleaning blade, and the surface of the image carrier are substantially closed. Thus, a minute space is formed along the upper edge of the tip surface of the cleaning blade. For this reason, the toner scraped off at the upper edge of the tip surface of the cleaning blade scatters only in the minute space,
Basically, the toner is further accumulated on the upper surface of the toner in the minute space without flowing out of the minute space. In addition, both ends (both ends in the direction along the upper edge of the blade tip surface) in the micro space may be openings, but even in such a case, the openings are very small openings and flow out through the openings. The amount of fog toner that can be produced is extremely small. Therefore, according to the image forming apparatus of the first aspect, the inside of the apparatus due to the toner can be minimized.

As a conventional cleaning device, as shown in FIG. 5A or 5B, a contact portion is provided below a contact portion C between the image carrier 1 rotating in the direction of arrow A and the cleaning blade 3. Space S provided at an interval from C
It is known that toner is deposited on the paper and various foreign substances precipitated from the paper are removed by the deposited toner (Japanese Patent Laid-Open No. 1-161288). 2. The toner is deposited in a space S provided below the contact portion C between the cleaning blade 3 and the contact portion C at a distance from the contact portion C, and the upper surface of the toner is the tip end surface of the cleaning blade as in the invention of claim 1. Since the toner is not deposited up to the position in contact with the lower edge, the above-described operation and effect according to the first aspect cannot be obtained.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the cleaning blade contacts the image carrier below a contact portion between the image carrier and the cleaning blade. Is provided with a sheet for rinsing the toner scraped off by the blade, so that the toner scraped off by the blade is scooped by the rake sheet. Since the stacking member is provided integrally with the rake sheet, the following operation and effect can be further obtained. That is, since the rake sheet is in contact with the image carrier, it slightly vibrates according to the rotation of the image carrier. This minute vibration is also transmitted to the stacking member provided integrally with the rake sheet, and the stacking member also vibrates minutely. For this reason, the upper surface of the toner deposited by the action of the deposition member is leveled by the slight vibration of the deposition member and the fine vibration of the image carrier. Therefore, according to the image forming apparatus of the second aspect,
The above-mentioned minute space is better formed, and as a result,
The inside of the apparatus due to the toner can be further reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a schematic front cross-sectional view showing a first embodiment of an image forming apparatus according to the present invention, FIG. 2 is an enlarged view showing a main part of the image forming apparatus, and FIG. It is. This image forming apparatus is an apparatus that can form a full-color image using a developing device using four color toners of yellow (Y), cyan (C), magenta (M), and black (K).

In FIG. 1, reference numeral 10 denotes a photoreceptor as an image carrier, which is rotationally driven in a direction indicated by an arrow by an appropriate driving means (not shown). Around the photoreceptor 10, along a rotation direction thereof, a charging roller 12 as a charging unit,
Developing roller 13 (Y, C, M, K) as developing means,
An intermediate transfer device 30 and a cleaning device 20 are provided.

The charging roller 12 contacts the outer peripheral surface of the photoconductor 10 to uniformly charge the outer peripheral surface. An outer peripheral surface of the uniformly charged photoconductor 10 is subjected to selective exposure L according to desired image information by an exposure unit (not shown), and an electrostatic latent image is formed on the photoconductor 10 by the exposure L. You. This electrostatic latent image is developed with toner applied by a developing roller 13. In this embodiment, a developing roller 13Y for yellow, a developing roller 13C for cyan, a developing roller 13M for magenta, and a developing roller 13K for black are provided as developing rollers. These developing rollers 13Y, 13C, 13M, and 13K can selectively contact the photoconductor 10, and when they come into contact with each other, apply any one of yellow, cyan, magenta, and black toner to the photoconductor 10. The electrostatic latent image on the photoconductor 10 is developed by being applied to the surface of the photoconductor 10. The developed toner image is
The image is transferred onto an intermediate transfer belt 36 as an intermediate transfer body described later (see the primary transfer unit Tr1).

After the transfer, the cleaning device 20
A photoconductor blade (cleaning blade) 21 for scraping off toner (residual toner) remaining on and adhering to the outer peripheral surface of the photoconductor 10, a scooping sheet 22 for the toner scraped off by the blade 21 and falling, A stacking section 23 for stacking the falling toner, and the stacking section 23
A receiving portion 24 for receiving the toner overflowing from the container, a screw 25 for transporting the toner in the receiving portion 24 to a waste toner bottle (not shown), and a case 26. The upper part of the blade 21 is fixed to the blade holder 27. The blade holder 27 has both ends (both ends in a direction orthogonal to the paper surface) swingably attached to side portions 26a, 26a (only one shown) of the case 26 by shafts 27a, 27a (only one is shown). I have. A blade urging spring (compression coil spring) 28 is provided between the case 26 and the blade holder 27, and is clearly shown in FIG. 3 by the urging force of the blade urging spring 28 and the elastic force of the blade 21 itself. Like, blade 2
The upper edge 21a of the first end surface 21c comes into contact with the surface of the photoconductor 10.

As clearly shown in FIG. 3, the feature of this embodiment is that the toner T scraped off by the blade 21 is deposited at least to a position where its upper surface T1 is in contact with the lower edge 21b of the tip surface 21c of the blade 21. Deposition member 23b to be deposited
Is provided. That is, the stacking unit 23 in this embodiment includes the surface 11 of the photoconductor 10, the rake sheet 22, and the plate-like stacking member 23b attached to the rake sheet 22 via the spacer 23a. Is formed. The spacer 23a and the stacking member 23b extend in a direction orthogonal to the paper surface, and the stacking portion 23 is provided over the entire length below the tip surface 21c of the blade 21. An interval 23d is formed between the upper end 23c of the accumulation member 23b and the blade 21. Through this interval 23d, excess toner among the toner T accumulated in the accumulation section 23 as indicated by an arrow T2. It overflows into the receiving portion 24. Stacking member 2
The height of the upper end 23c of the blade 3b is the tip surface 21c of the blade 21.
The lower edge 21b is substantially the same height or higher.

As shown in FIGS. 1 and 2, the rake sheet 2
2 is fixed to the case 26, and the bottom of the spacer 23 a is supported by the case 26. The spacer 2
It is desirable that 3a be made of a porous material (for example, sponge) so as to suppress scattering of the toner falling onto the spacer 23a at the initial stage.

The above-described cleaning device is configured as a unit by a case 26, and is detachably attached to a frame (not shown) of the image forming apparatus main body.

The intermediate transfer device 30 includes a driving roller 31,
It has four driven rollers 32, 33, 34, 35, an endless intermediate transfer belt 36 as an intermediate transfer member stretched over these rollers, a secondary transfer roller 37, and a cleaning unit 38. ing.

The driving roller 31 is driven to rotate at substantially the same peripheral speed as the photosensitive member 10 by engaging a gear (not shown) fixed to an end thereof with a driving gear (not shown) of the photosensitive member 10. Therefore, the intermediate transfer belt 36 is circulated in the direction indicated by the arrow at substantially the same peripheral speed as the photoconductor 10. The driven roller 35 is a primary transfer roller, and is pressed against the photoconductor 10 via the intermediate transfer belt 36, and forms a primary transfer portion Tr1 between the photoconductor 10 and the intermediate transfer belt 36 at the pressed portion. ing. Drive roller 31
Is provided with an electrode roller (not shown) via an intermediate transfer belt 36, and a primary transfer voltage is applied to the intermediate transfer belt 36 via the electrode roller.
The driven roller 32 is a tension roller, and urges the intermediate transfer belt 36 in the tension direction by an urging means (not shown). The driven roller 33 is a backup roller that forms the secondary transfer unit Tr2. A secondary transfer roller 37 is opposed to the backup roller 33 via an intermediate transfer belt 36. The secondary transfer roller 37 is
It can be moved toward and away from the intermediate transfer belt 36 by a contacting / separating mechanism (not shown). A secondary transfer voltage is applied to the secondary transfer roller 37. The driven roller 34 is a backup roller for the cleaning unit 38. The cleaning unit 38 is configured by an intermediate transfer member blade that comes into contact with the intermediate transfer belt 36 and scrapes off the remaining toner (secondary transfer residual toner) on the outer peripheral surface thereof. The intermediate transfer member blade can be moved toward and away from the intermediate transfer belt 36 by a contact / separation mechanism (not shown). The toner scraped off by the intermediate transfer member blade 38 is received by a receiving portion (not shown), and is conveyed to a waste toner bottle by a screw (not shown).

In the course of circulating the intermediate transfer belt 36, the toner image on the photoreceptor 10 is transferred onto the intermediate transfer belt 36 in the primary transfer portion Tr1, and the toner image transferred onto the intermediate transfer belt 36 is In the secondary transfer section Tr2, the image is transferred onto a recording medium P such as a sheet to be transferred, which is supplied to the secondary transfer roller 37. Recording medium P
Is supplied from a sheet feeding device (not shown) and supplied to the secondary transfer unit Tr2 at a predetermined timing.

The operation of the entire image forming apparatus as described above is as follows. (I) When a print command signal (image forming signal) from a not-shown host computer or the like (a personal computer or the like) is input to the control unit of the image forming apparatus, the tension roller 32 operates to put the intermediate transfer belt 36 in a stretched state. Becomes
The photosensitive member 10 and the developing roller 1 are driven by driving means (not shown).
3, and the intermediate transfer belt 36 is driven to rotate. (Ii) The outer peripheral surface of the photoconductor 10 is uniformly charged by the charging roller 12. (Iii) Selectively exposing the outer peripheral surface of the uniformly charged photoconductor 10 according to image information of the first color (for example, magenta (M)) by an exposing unit (not shown),
An electrostatic latent image for magenta is formed. (Iv) The first color (for example, magenta) is applied to the photoconductor 10.
Only the developing roller 13 </ b> M comes into contact, whereby the electrostatic latent image is developed, and a toner image of the first color (for example, magenta) is formed on the photoconductor 10. (V) A primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied to the intermediate transfer belt 36, and the toner image formed on the photoconductor 10 is transferred to the primary transfer unit Tr1, that is, the photoconductor 10 and the intermediate transfer belt. The toner image is transferred onto the intermediate transfer belt 36 at a pressure contact portion Tr1 with the intermediate transfer belt 36. At this time, the secondary transfer roller 37 and the cleaning unit 38 are separated from the intermediate transfer belt 36. (Vi) After the toner (primary residual toner) remaining on the photoreceptor 10 is removed by the photoreceptor blade 21, the photoreceptor 1 is discharged by discharging light from a discharging unit (not shown).
0 is eliminated. (Vii) The above operations (ii) to (vi) are repeated as necessary. That is, the second color, the third color, and the fourth color are repeated in accordance with the content of the print command signal, and the toner images corresponding to the content of the print command signal are superimposed on the intermediate transfer belt 36 to form an intermediate image. It is formed on the transfer belt 36. (Viii) The recording medium P is supplied at a predetermined timing, and immediately before or after the leading end of the recording medium P reaches the secondary transfer portion Tr2 (in short, at a desired position on the recording medium P, on the intermediate transfer belt 36). (At the timing when the toner image of the intermediate transfer belt is transferred).
6, the secondary transfer voltage is applied, and the toner image (basically a full-color image) on the intermediate transfer belt 36 is transferred onto the recording medium P. Further, the intermediate transfer member blade 38 comes into contact with the intermediate transfer belt 36, and the toner (secondary residual toner) remaining on the intermediate transfer belt 36 after the secondary transfer is removed. (Ix) The toner image is fixed on the recording medium P by passing the recording medium P through a fixing device (not shown).
The recording medium P is discharged out of the apparatus. (X) If the image forming signal is not input for a predetermined time or the power of the apparatus is turned off after the operations (i) to (ix) are performed, the tension transfer roller 36 is operated to operate the intermediate transfer belt 36 in a stretched state. Is released.

According to the above-described image forming apparatus, the following functions and effects can be obtained. The toner remaining on the image carrier 10 after the transfer of the toner image on the image carrier 10, which is a rotating body carrying the toner image, is scraped off by the cleaning blade 21 that comes into contact with the surface of the image carrier 10. Removed. The blade 21 has its tip surface 21c
Since the upper edge 21a contacts the surface of the image carrier 10, the residual toner is scraped off by the upper edge 21a. According to the image forming apparatus of this embodiment, the toner T scraped off by the cleaning blade 21
At least the upper surface T1 of the cleaning blade 2
As shown in FIG. 3, since the deposition member 23 b is provided for depositing to a position in contact with the lower edge 21 b of the front end surface 21 c of the cleaning blade 21, the lower edge 21 b of the front end surface 21 c of the cleaning blade 21 is provided by the deposition member 23 b. The upper edge 21 of the blade 21 tip surface 21c, which is substantially closed by the upper surface T1 of the toner T deposited up to a position where the toner T contacts the tip surface, the tip surface 21c of the cleaning blade 21, and the surface 11 of the image carrier 10.
A small space A along the line a is formed. For this reason, the upper edge 2 of the tip end surface 21c of the cleaning blade 21
The toner scraped in 1a is scattered only in the minute space A, and basically does not flow out of the minute space A, but on the upper surface T1 of the deposited toner T in the minute space A. Will be further deposited. In this embodiment, both ends (both ends in a direction along the upper edge 21a of the blade tip surface (a direction perpendicular to the paper surface)) A1 in the micro space A are side seals (not shown) (for example, an image carrier). 10 is a member for preventing toner from leaking in the lateral direction), but may be an opening when such a side seal is not provided. However, even in this case, since the opening A1 is a very small opening, the amount of the mist toner that can flow out through the opening A1 is extremely small. In any case, according to such an image forming apparatus, contamination inside the apparatus due to toner can be reduced as much as possible.

<Second Embodiment> FIG. 4 is a partially omitted enlarged view showing a main part of an image forming apparatus according to a second embodiment of the present invention. In the figure, the same or corresponding parts as in the first embodiment are denoted by the same reference numerals.

This embodiment is different from the first embodiment in that a plate-like deposition member 23b is formed integrally with the rake sheet 22 so as to be bent in a substantially "<" shape. The other points are the same. The stacking member 23b according to this embodiment has a lower part 2b.
3b1 is provided integrally with the lower portion 22a of the rake sheet 22 by an adhesive layer (for example, an adhesive) 29a;
The rake sheet 22 and the stacking member 23b are fixed to the mounting surface 26b of the case 26 by an adhesive layer 29b shorter than the adhesive layer 29a (shorter in the vertical direction (the rotation direction of the image carrier 10) in FIG. 4). I have. The adhesive layer 29 b for the case 26 is formed by the rake sheet 22 and the stacking member 2.
3b is shorter than the adhesive layer 29a for fixing the rake sheet 3b, a portion H3 of the fixing portion between the rake sheet 22 and the stacking member 23b is a portion not backed up by the case 26. Becomes The rake sheet 22 comes into contact with the photoreceptor 10 and the photoreceptor 1
When a minute vibration is caused in accordance with the rotation of 0, a vibration transmitting portion for transmitting the vibration to the deposition member 23b is formed. That is, the micro vibration of the rake sheet 22 is also transmitted to the deposition member 23b through the vibration transmission unit H3, and the deposition member 23b also microvibrates. Therefore, according to this embodiment, the following operation and effect can be obtained in addition to the operation and effect of the first embodiment. That is, since the deposition member 23b vibrates finely together with the rake sheet 22, the toner T deposited by the action of the deposition member 23b is subjected to the fine vibration of the deposition member 23b and the fine vibration of the image carrier 10. The upper surface T1 is substantially smoothed. Therefore, the above-mentioned minute space A is formed more favorably, and as a result, contamination inside the apparatus by the toner can be further reduced. The blade 21 also vibrates slightly when it comes into contact with the image carrier 10, and the depositing member 23b in the first embodiment also vibrates to some extent. Also, the upper surface T1 of the deposited toner T
Is obtained to a certain extent.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be appropriately modified and implemented within the scope of the present invention. For example, in the above embodiment, the case where the image carrier is a photoconductor has been described. However, the present invention is also applicable to a case where the image carrier is an intermediate transfer member. Further, in the above embodiment, the case where the image carrier (photoconductor) is cylindrical has been described, but the present invention is also applicable to the case where the image carrier is belt-shaped. In addition, in each figure of FIGS. 1-3, although the shape of a member is slightly different, any shape can be employ | adopted.

[0024]

According to any of the image forming apparatuses according to the first and second aspects, contamination in the apparatus due to toner can be reduced as much as possible. Further, according to the image forming apparatus of the second aspect, the inside of the apparatus due to the toner can be further reduced.

[0025]

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view showing a first embodiment of an image forming apparatus according to the present invention.

FIG. 2 is an enlarged view of a main part with a part omitted.

FIG. 3 is an operation explanatory view.

FIG. 4 is a partially omitted enlarged view showing a main part of an image forming apparatus according to a second embodiment of the present invention.

FIGS. 5A and 5B are explanatory diagrams of a conventional technique.

[Explanation of symbols]

 T Toner T1 Upper surface 10 Photoconductor (image carrier) 11 Surface 21 Cleaning blade 21a Upper edge 21b Lower edge 21c Tip surface 22 Rake sheet 23b Stacking member

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsunori Kitazawa 3-3-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (reference) 2H034 BF01 CA04

Claims (2)

[Claims] An image bearing member, which is a rotating member for carrying a toner image, is in contact with the surface of the image bearing member, and after the toner image on the image bearing member has been transferred, remains on the image bearing member. A cleaning blade that scrapes off the toner that is present, wherein the upper edge of the tip surface of the cleaning blade contacts the surface of the image carrier, and the toner scraped off by the cleaning blade is provided on at least an upper surface thereof. An image forming apparatus, wherein a stacking member is provided for stacking to a position in contact with a lower edge of the front end surface of the cleaning blade. 2. A scooping sheet for scooping toner which is in contact with the image carrier below a contact portion between the image carrier and a cleaning blade and scrapes off the toner by the cleaning blade. The image forming apparatus according to claim 1, wherein the stacking member is provided integrally.