JP5212027B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a composite machine of these, and after transferring a toner image from an image holding member that holds and moves the toner image and then contacts a solid lubricant. In the image forming apparatus in which the lubricant is supplied from the rotating lubricant supply member to the surface of the image holding member, the residue such as toner remaining on the surface of the image holding member after the toner image is transferred is Suppressing adhesion to the lubricant supply member and the solid lubricant, the lubricant supply member stably supplies the lubricant to the surface of the image holding member, so that stable image formation can be performed over a long period of time. It is characterized by the points.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a combination of these, an image holding member that holds and moves a toner image, for example, a photosensitive drum on which a toner image is formed or a photosensitive drum is formed. In the intermediate transfer body to which the toner image is transferred, after the toner image is transferred from such an image holding member to a transfer member such as a recording medium or an intermediate transfer body, a cleaning blade or the like is applied to the surface of the image holding member. A cleaning member is brought into pressure contact to remove a residue such as toner remaining on the surface of the image holding member.

  Here, the cleaning member is pressed against the surface of the image holding member after the toner image is transferred as described above, and the operation of removing the residual toner and the like remaining on the surface of the image holding member is lengthened. If it continues, there are problems such that the cleaning member is worn and the cleaning performance is deteriorated, and the surface of the image holding member is worn and the life of the image holding member is shortened.

  For this reason, conventionally, a lubricant such as metal soap is supplied from a lubricant supply means to the surface of an image holding member on which a toner image is transferred to a recording medium or the like, and the surface of the image holding member and the cleaning member are supplied by this lubricant. The surface of the image holding member is improved, and the toner image formed on the surface of the image holding member is appropriately transferred to the transfer member. Has been done.

  Conventionally, in supplying a lubricant from the lubricant supply means to the surface of the image holding member after the toner image is transferred to the transfer member as described above, as shown in Patent Document 1, a solid state is used. After the lubricant is scraped off from the lubricant by the brush roll, the brush roll is brought into contact with the surface of the image holding member after the toner image is transferred, and the scraped lubricant is supplied to the surface of the image holding member. A cleaning member is pressed against the surface of the image holding member, and the cleaning member removes residual toner and the like remaining on the surface of the image holding member and applies the supplied lubricant to the surface of the image holding member. What has been proposed has been proposed.

  However, when the cleaning member removes residual toner or the like remaining on the surface of the image holding member, the lubricant is applied by bringing the brush roll into contact with the surface of the image holding member. The toner remaining on the surface of the image holding member adheres to and accumulates on the brush roll, and the toner remaining on the brush roll adheres to the surface of the solid lubricant. As a result, there is a problem that the lubricant cannot be properly scraped off from the solid lubricant by the brush roll, and the lubricant is not properly applied to the surface of the image holding member.

  Conventionally, as described in Patent Documents 2 to 4, image holding is performed in order to prevent the toner or the like remaining on the surface of the image holding member from adhering to the brush roll as described above. After the toner and other residues remaining on the surface of the member are removed by the cleaning member, the above-described brush roll is brought into contact with the surface to supply the lubricant to the surface of the image holding member. The end of the leveling member is pressed against the surface of the image holding member, the lubricant supplied to the surface of the image holding member is pressed by the leveling member, and the lubricant is applied to the surface of the image holding member in the form of a film. What has been made to be proposed is proposed.

  However, in the case where a leveling member for applying the supplied lubricant to the surface of the image holding member is provided separately from the cleaning member for removing the residual toner and the like remaining on the surface of the image holding member in this way, There is a problem that the cost is high and the apparatus is enlarged.

  Further, conventionally, the removal member is brought into contact with the brush roll on the downstream side in the rotation direction of the brush roll from the position where the lubricant is supplied to the surface of the image holding member, and the residue such as toner adhered to the brush roll. Is also removed from the brush roll.

However, even when the removal member is brought into contact with the brush roll in this way to remove the residue such as toner adhering to the brush roll from the brush roll, the residue such as toner adhering to the brush roll is removed. It cannot be removed sufficiently from the brush roll, and the residue such as toner still adheres to and accumulates on the brush roll and adheres to the surface of the solid lubricant. There is a problem in that it becomes impossible to scrape off and the lubricant cannot be properly applied to the surface of the image holding member.
JP 2003-57996 A JP 2006-251751 A JP 2006-259450 A JP 2007-79468 A

  According to the present invention, a toner image is transferred from an image holding member that holds and moves a toner image, and then a lubricant is supplied to the surface of the image holding member from a lubricant supply member that rotates while contacting the solid lubricant. An object of the present invention is to solve the above-described problems in the image forming apparatus.

  That is, in the present invention, when the lubricant is supplied to the surface of the image holding member after transferring the toner image as described above from the lubricant supply member that rotates while contacting the solid lubricant, the image holding is performed. Residues such as toner remaining on the surface of the member are prevented from adhering to the lubricant supply member and the solid lubricant, and the lubricant is stably and appropriately supplied to the surface of the image holding member by the lubricant supply member. Therefore, an object is to enable stable image formation over a long period of time.

In the present invention, in order to solve the above-described problems, the image is placed at a position downstream of the image holding member in the moving direction from the position where the toner image is transferred from the image holding member that holds and moves the toner image. As a lubricant supply means for supplying a lubricant to the surface of the holding member, a solid lubricant along the longitudinal direction of the image holding member, and rotating while contacting the solid lubricant, the lubricant is applied to the surface of the image holding member. Provided are a lubricant supply member to be supplied and a removal member for removing deposits adhering to the lubricant supply member on the downstream side in the rotation direction of the lubricant supply member from the position where the lubricant is supplied to the surface of the image holding member. In the image forming apparatus, the charge polarity of the surface of the image holding member is the same as the normal charge polarity of the toner, and the lubricant supply member and the removal member have the same polarity as the normal charge polarity of the toner, respectively. bias By applying a pressure, per To an electric field is applied in the direction to send the regularly charged toner on the image holding member between the lubricant supply member and the image holding member, a lubricant supply bias voltage is applied to the lubricant supply member Vbr When the removal bias voltage Vfl for applying to the removal member, said lubricant lubricant from the supply member and the surface potential Vi of the image holding member in a position to be supplied | Vfl |> | Vbr |> | Vi | conditions It was made to satisfy.

That is, in the image forming apparatus described above, a developing method is reversal development system, in what charge polarity of the surface of the image holding member is the same polarity as the charging polarity of the regular toner, the above-mentioned lubricant supply The surface potential Vr of the image holding member at the position where the lubricant is supplied from the member to the surface of the image holding member, the lubricant supply bias voltage Vbr, and the removal bias voltage Vfl are | Vfl |> | Vbr |> | Vi | it was to meet the conditions.

  In the image forming apparatus, the lubricant supplied from the lubricant supply member to the surface of the image holding member is properly supplied with the lubricant supplied to the surface of the image holding member. It is preferably charged to the same polarity as the charged polarity.

  In the image forming apparatus, for example, a brush roll, a foam roll, a solid roll, or the like can be used as the lubricant supply member. However, the image is retained by appropriately scraping the lubricant from the solid lubricant. In order to supply the surface of the member, it is preferable to use a brush roll.

  In the image forming apparatus of the present invention, when supplying the lubricant from the lubricant supplying means to the surface of the image holding member after the toner image is transferred, the image is held by rotating while contacting the solid lubricant. A bias voltage having the same polarity as the normal charging polarity of the toner is applied to the lubricant supply member supplied to the surface of the member and the removal member that removes the adhering matter adhering to the lubricant supply member. Since an electric field in the direction of sending the normally charged toner to the image holding member is applied between the lubricant supply member and the image holding member, the normally charged toner remaining on the surface of the image holding member after the transfer is Adhering to the lubricant supply member is prevented.

In the image forming apparatus of the present invention, as described above, a bias voltage having the same polarity as the normal charging polarity of the toner is applied to the lubricant supply member and the removal member, respectively, and applied to the lubricant supply member. Since the lubricant supply bias voltage Vbr and the removal bias voltage Vfl applied to the removal member satisfy the condition of | Vfl |> | Vbr |, the reverse remains on the surface of the image holding member after transfer. Even if charged toner or the like adheres to the lubricant supply member, the adhering material such as the reversely charged toner attached to the lubricant supply member is electrically attracted to the removal member and is lubricated by the removal member. It will be appropriately removed from the agent supply member.

  As a result, in the image forming apparatus of the present invention, the residue such as toner remaining on the surface of the image holding member is suppressed from adhering to the lubricant supply member and the solid lubricant, and the lubricant is supplied by the lubricant supply member. It becomes possible to stably and appropriately supply the surface of the image holding member and to perform stable image formation over a long period of time.

  Further, in the image forming apparatus of the present invention, when the lubricant supplied to the surface of the image holding member is charged to the same polarity as the normal charging polarity of the toner as described above, the lubricant supply member and the image holding device are held. The lubricant is sent to the image holding member by the electric field in the direction in which the normally charged toner acting between the member and the member is sent to the image holding member, and the lubricant is further supplied from the lubricant supply member to the surface of the image holding member. It will be supplied appropriately.

  Next, an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image forming apparatus according to the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In the image forming apparatus according to this embodiment, as shown in FIG. 1, four developing devices 11 that contain negatively charged toners of different colors of yellow, magenta, cyan, and black are provided. Corresponding to the developing device 11, four photosensitive drums 10 in the form of drums are provided as image holding members.

  In this image forming apparatus, each photosensitive drum 10 is rotated, and the surface of each photosensitive drum 10 is charged to a predetermined negative potential by the charging device 12, and each photosensitive member thus charged is charged. The body drum 10 is exposed according to the image data by the latent image forming device 13 to form an electrostatic latent image with a negative potential reduced on the surface of each photoreceptor drum 10.

  Next, with respect to each photosensitive drum 10 on which the electrostatic latent image is formed in this manner, each color toner is opposed to each photosensitive drum 10 by each developing roller 11a provided in each corresponding developing device 11. As shown in FIG. 2, a negative developing bias voltage is applied to each developing roller 11a from the developing bias power source 11b to cause each negatively charged toner to have a negative potential lowered. The toner image is supplied to the portion of the electrostatic latent image and subjected to reversal development, and a toner image of each color is formed on the surface of each photosensitive drum 10.

  Then, the toner images of the respective colors formed on the respective photosensitive drums 10 are respectively transferred to the intermediate transfer body 15 in the form of an endless belt that is driven around the roller 14 and is in the form of a roller. A primary image is sequentially transferred by the transfer device 16 to form a full-color toner image on the intermediate transfer member 15.

  Next, the full-color toner image formed on the intermediate transfer member 15 in this way is guided to a position facing the secondary transfer device 17 formed into a roller shape by the intermediate transfer member 15, and the image forming apparatus The sheet-like recording medium S accommodated in the lower part is guided between the intermediate transfer member 15 and the secondary transfer device 17 by the feed roller 18, and is formed on the intermediate transfer member 15 by the secondary transfer device 17. The full color toner image is secondarily transferred to the recording medium S.

  Thereafter, the recording medium S to which the full-color toner image is transferred is guided to the fixing device 19, and the transferred full-color toner image is fixed to the recording medium S, and then the recording in which the full-color toner image is fixed as described above. While discharging the medium S, the toner remaining on the intermediate transfer body 15 without being transferred to the recording medium S is removed from the intermediate transfer body 15 by the second cleaning member 21 provided in the second cleaning device 20. Let

  In the image forming apparatus of this embodiment, as shown in FIG. 1, the lubricant supply means 30 is provided on the surface of each photosensitive drum 10 after the toner image is transferred to the intermediate transfer body 15 as described above. After that, the lubricant is supplied to the surface of each photoconductive drum 10, and then the cleaning member 40 is pressed against the surface of each photoconductive drum 10 to remove residues such as toner remaining on the surface of each photoconductive drum 10. The lubricant supplied to the surface of the drum 10 is uniformly applied to the surface of each photosensitive drum 10.

  Here, in this embodiment, when supplying the lubricant to the surface of the photoreceptor drum 10 after the transfer by the lubricant supply means 30 as described above, as shown in FIG. A brush roll 31 that rotates in contact with the surface of the photoconductive drum 10 is provided along the axial direction of the photoconductive drum 10, and a solid lubricant 32 provided along the axial direction of the photoconductive drum 10 is provided from a spring member. The pressing means 33 is pressed against the brush roll 31, and the rotating brush roll 31 scrapes off the lubricant from the solid lubricant 32 and supplies it to the surface of the photosensitive drum 10.

  In addition, the removal member 34 is brought into contact with the brush roll 31 at a position downstream of the position in the rotation direction of the brush roll 31 with respect to the position where the lubricant is supplied to the surface of the photosensitive drum 10 in this way. The adhering matter adhering to the brush roll 31 is removed.

  In this embodiment, a negative lubricant supply bias voltage Vbr having the same polarity as the toner charging polarity is applied from the first bias power source 31a to the brush roll 31 and the removal member 34 is applied. Then, a negative removal bias voltage Vfl having the same polarity as the charging polarity of the toner is applied from the second bias power source 34a, and scraped off from the solid lubricant 32 by the brush roll 31 to the surface of the photosensitive drum 10. The supplied lubricant is charged negatively with the same polarity as the charging polarity of the toner.

  Here, as described above, from the first bias power supply 31a and the second bias power supply 34a, a negative lubricant supply bias voltage Vbr having the same polarity as the toner charging polarity with respect to the brush roll 31 and the removing member 34, respectively. In applying the removal bias voltage Vfl, the surface potential Vi of the negatively charged photosensitive drum 10 at the position where the lubricant is supplied, the lubricant supply bias voltage Vbr, and the removal bias voltage Vfl are | Vfl. The condition of |> | Vbr |> | Vi | is satisfied.

  The surface potential Vi of the photosensitive drum 10 at the position where the lubricant is supplied and the lubricant supply bias voltage Vbr applied to the brush roll 31 satisfy the condition | Vbr |> | Vi |. Then, an electric field is applied between the photosensitive drum 10 and the brush roll 31 in the direction in which the normally charged negative toner is sent to the photosensitive drum 10, and the normally charged negative toner adheres to the brush roll 31. The above-described lubricant of the same polarity as the toner and negatively charged is appropriately supplied from the brush roll 31 to the surface of the photosensitive drum 10.

  In addition, the reversely charged toner or the like that is positively charged with a reverse polarity comes to adhere to the brush roll 31 from the photosensitive drum 10, but the lubricant supply bias voltage Vbr applied to the brush roll 31 as described above, Since the removal bias voltage Vfl applied to the removal member 34 satisfies the condition of | Vfl |> | Vbr |, the brush roller 31 removes the reversely charged toner or the like adhering to the brush roll 31. Is electrically attracted to the removing member 34 at a position in contact with the brush roller 31, and is appropriately removed from the brush roll 31 by the removing member 34.

  As a result, toner and other residues remaining on the surface of the photosensitive drum 10 adhere to the brush roll 31, and toner and other residues adhering to the brush roll 31 pass from the brush roll 31 to the solid lubricant 32. To prevent the residue such as toner from adhering to the surface of the solid lubricant 32, and the brush roller 31 stably and appropriately scrapes off the lubricant from the solid lubricant 32. The scraped lubricant is appropriately supplied from the brush roll 31 to the surface of the photosensitive drum 10, so that stable image formation can be performed over a long period of time.

  In this embodiment, the brush roll 31 is used as the lubricant supply member 31 that supplies the lubricant to the surface of the photosensitive drum 10. However, instead of the brush roll 31, a foam roll or a solid roll is used. Can also

  Next, a commercially available copier (Konica Minolta Business Technologies, Inc .: Bizhub C650) that performs reversal development using a negatively charged toner is modified, and the lubricant supply means as shown in the above embodiment is exposed to light. The photosensitive drum is provided upstream of the cleaning member for removing the toner remaining on the surface of the photosensitive drum.

  Here, in the above-mentioned lubricant supply means, a lubricant made of zinc stearate formed into a predetermined shape is used as the solid lubricant.

Further, as the brush roll, a conductive nylon fiber having a fiber thickness of 6 dtex, a fiber resistance value of 10 ⁸ Ω, and a fiber height of 2.5 mm on a base fabric having a thickness of 0.5 mm and a fiber density of A brush base cloth provided so as to be 1.2 × 10 ⁵ pieces / inch ² was attached to the outer periphery of a metal roller having a diameter of 6 mm.

  Then, the solid lubricant is pressed against the brush roll with a force of 2 N / m by a pressing means made of a spring member, the brush roll is rotated at a rotational speed of 350 rpm, and the solid material is solidified by the brush roll. The lubricant was scraped off from the lubricant and supplied to the photosensitive drum. The lubricant scraped off by the brush roll in this way was charged negatively with the same polarity as the charged polarity of the toner.

  Moreover, as said removal member, the sheet metal of SUS304 which became thickness 1mm was used, and it provided so that the edge part of this removal member might bite 0.5 mm with respect to said brush roll.

  The cleaning member is a polyurethane rubber made of polyurethane rubber having a hardness (JIS-A) of 77 degrees and a rebound resilience value of 20%. The end of the cleaning member is used as a cleaning member. It protruded 8 mm from the holding member, and was brought into contact with the surface of the photosensitive drum with a contact angle of 10 ° and a contact force of 20 N / m.

  As shown in Table 1 below, in Example 1, a negative bias voltage having the same polarity as the toner charging polarity is applied to the brush roll and the removal member from the first bias power source and the second bias power source. The lubricant supply bias voltage Vbr applied to the brush roll was set to -300V, and the removal bias voltage Vfl applied to the removal member was set to -500V.

  In Comparative Example 1, the brush roll was grounded without applying the lubricant supply bias voltage Vbr, and was floated without applying the removal bias voltage Vfl to the removal member.

  Further, in Comparative Example 2, the lubricant supply bias voltage Vbr of −300 V, which is the same as that of Example 1, was applied to the brush roll, while the removal member was floated without applying the removal bias voltage Vfl. .

  In Comparative Example 3, a positive bias voltage having a polarity opposite to the charging polarity of the toner or the lubricant is applied to the brush roll and the removing member from the first bias power source and the second bias power source. The lubricant supply bias voltage Vbr applied to the brush roll was set to + 200V, and the removal bias voltage Vfl applied to the removal member was set to + 400V.

  In each of the image forming apparatuses described above, the surface potential Vi of the photosensitive drum at the position where the lubricant is supplied from the brush roll to the photosensitive drum is -100V.

  Then, using the image forming apparatuses of Example 1 and Comparative Examples 1 to 3 set to the above conditions, each color having an area ratio of 5% under environmental conditions of a temperature of 23 ° C. and a humidity of 65% RH, respectively. After continuous printing of 100,000 Aya character images (total area ratio 20%), the toner adhesion to the solid lubricant and the consumption amount of the solid lubricant were examined. The results are shown in Table 1 below. Indicated.

  Here, regarding toner fixation to the solid lubricant, ○ when the toner is not fixed to the solid lubricant, × when the toner is fixed to the solid lubricant, and consumption of the solid lubricant About, the case where the consumption amount of the solid lubricant is 1.3 g or more is indicated by ◯, and the case where the consumption amount of the solid lubricant is less than 1.3 g is indicated by ×.

  Further, after printing 100,000 sheets as described above, a solid image and a blank image are continuously printed under environmental conditions of a temperature of 10 ° C. and a humidity of 15% RH. The cleaning state was evaluated, and the results are shown in Table 1 below.

  Here, in the evaluation of the cleaning state, the adhesion of the toner to the above-described blank paper image was examined, and the case where there was no toner adhesion was indicated by ◯, and the case where the toner was adhered was indicated by ×.

  Further, in the image forming apparatuses of Example 1 and Comparative Example 3 described above, after printing 100,000 sheets as described above, the friction coefficient on the surface of the photosensitive drum is determined by a friction coefficient measuring probe (HEIDON). Co., Ltd .: Tribogear Muse 94i) Measured with a 100% cotton flannel affixed, ○ when the coefficient of friction on the surface of the photosensitive drum is less than 0.3, and x when 0.3 or more. It was shown in 1.

  As a result, as in the present invention, a negative bias voltage that is the same as the toner charging polarity is applied to the brush roll and the removing member, and the lubricant supply bias voltage Vbr to be applied to the brush roll and the removing member are applied. Example 1 in which the removal bias voltage Vfl to be applied and the surface potential Vi of the photosensitive drum at the position where the lubricant is supplied from the brush roll satisfy the condition of | Vfl |> | Vbr |> | Vi |. In such a case, the toner does not adhere to the solid lubricant, the lubricant is sufficiently scraped off from the solid lubricant by the brush roll, and the lubricant is appropriately supplied to the surface of the photosensitive drum. In addition, the occurrence of poor cleaning is prevented, the increase in the coefficient of friction on the surface of the photosensitive drum is suppressed, and the wear of the photosensitive drum and the cleaning member is also reduced. It came to be sealed.

  On the other hand, in Comparative Examples 1 and 2, the toner is fixed to the solid lubricant, and the lubricant cannot be properly scraped off from the solid lubricant by the brush roll. As a result, the lubricant was not properly supplied to the surface of the surface, resulting in poor cleaning.

  In the comparative example 3, the toner does not adhere to the solid lubricant, and the brush roll sufficiently scrapes the lubricant from the solid lubricant. Since a positive bias voltage of opposite polarity is applied, the scraped lubricant is electrically attracted to the brush roll and is not properly supplied to the surface of the photosensitive drum, resulting in poor cleaning. As this occurred, the coefficient of friction on the surface of the photosensitive drum increased, and the wear of the photosensitive drum and the cleaning member increased.

1 is a schematic explanatory view showing an image forming apparatus according to an embodiment of the present invention. In the image forming apparatus of the embodiment, a lubricant supply unit that supplies lubricant to the surface of the photosensitive drum is provided at a position downstream of the position where the toner image is transferred from the photosensitive drum in the moving direction of the photosensitive drum. It is the schematic explanatory drawing which showed the state.

Explanation of symbols

10 Photosensitive drum (image holding member)
DESCRIPTION OF SYMBOLS 11 Developing apparatus 11a Developing roller 11b Developing bias power supply 12 Charging apparatus 13 Exposure apparatus 14 Roller 15 Intermediate transfer body 16 Primary transfer apparatus 17 Secondary transfer apparatus 18 Feeding roller 19 Fixing apparatus 20 First cleaning apparatus 21 Cleaning blade 30 Lubricant supply means 31 Brush roll (lubricant supply member)
31a First bias power source 32 Solid lubricant 33 Pressing means 34 Removal member 34a Second bias power source 40 Cleaning member S Recording medium

Claims (4)

Lubricant supply means for supplying lubricant to the surface of the image holding member at a position downstream in the moving direction of the image holding member from a position where the toner image is transferred from the image holding member that holds and moves the toner image. A solid lubricant along the longitudinal direction of the image holding member, a lubricant supply member that rotates while contacting the solid lubricant and supplies the lubricant to the surface of the image holding member, and a lubricant for the image holding member. In the image forming apparatus provided with a removing member that removes deposits adhering to the lubricant supply member on the downstream side in the rotation direction of the lubricant supply member from the position to be supplied to the surface, the charged polarity of the surface of the image holding member Is the same polarity as the normal charging polarity of the toner, and a bias voltage having the same polarity as the normal charging polarity of the toner is applied to the lubricant supply member and the removal member, respectively, Holding member Normally-charged toner per To an electric field is applied in the direction to send the image holding member, and the lubricant supply bias voltage Vbr which is applied to the lubricant supply member, and removing the bias voltage Vfl for applying a removing member between the said lubricant An image forming apparatus, wherein the surface potential Vi of the image holding member at a position where the lubricant is supplied from the supply member satisfies a condition of | Vfl |> | Vbr | > | Vi | . The image forming apparatus according to claim 1 , wherein the lubricant supplied from the lubricant supply member to the surface of the image holding member is charged with the same polarity as the normal charging polarity of the toner. Image forming apparatus. 3. The image forming apparatus according to claim 1 , wherein the lubricant supply member is a brush roll. 4. The image forming apparatus according to claim 1 , wherein a residue remaining on the surface of the image holding member at a position downstream of the lubricant supply unit in the moving direction of the image holding member. 5. An image forming apparatus, comprising a cleaning member for removing water.

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