JP2009169226A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably supply a lubricant to a surface of a charging roller with simple constitution to suitably impart the lubricant to a surface of an image holding member when electrostatically charging the surface of the image holding member by the charging roller which rotates in contact with the surface of the image holding member, supplying the lubricant to the surface of the charging roller by a lubricant supply means, and imparting the lubricant from the charging roller to the surface of the image holding member. <P>SOLUTION: An image forming apparatus which electrostatically charges the surface of the image holding member by the charging roller 20 rotating in contact with the surface of the image holding member 1, supplies the lubricant to the surface of the charging roller by the lubricant supply means 30, and imparts the lubricant from the charging roller to the surface of the image holding member is provided with a surface layer 21 formed of an elastic material having unevenness on the surface of the charging roller. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these, and in particular, charges the surface of an image holding member with a charging roller that rotates in contact with the surface of the image holding member. In an image forming apparatus in which a lubricant is supplied to the surface of the charging roller by a lubricant supply means and this lubricant is applied from the charging roller to the surface of the image holding member, the surface of the charging roller can be formed with a simple configuration. This is characterized in that the lubricant is appropriately supplied and the lubricant is appropriately applied to the surface of the image holding member.

  In an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine of these, generally, an image holding member such as a photosensitive drum or a photosensitive belt is driven, and the surface of the image holding member is charged by a charging device. Thereafter, the charged image holding member is exposed in accordance with image data by an exposure device to form an electrostatic latent image on the surface of the image holding member, thus forming the electrostatic latent image. A toner is supplied from the developing device to the surface of the image holding member, and a toner image is formed on the surface of the image holding member.

  Then, after the toner image formed on the surface of the image holding member in this way is transferred to a transfer member such as a recording medium or an intermediate transfer member, a cleaning member is pressed against the surface of the image holding member, and this image is transferred. Residues such as toner remaining on the surface of the holding member are removed.

  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, as disclosed in Patent Document 1 and the like, a lubricant is supplied from a lubricant supply means to the surface of the image holding member after the toner image is transferred to the transfer member. The frictional resistance between the surface of the image holding member and the cleaning member is reduced, the releasability of the surface of the image holding member is increased, and the toner image formed on the surface of the image holding member is appropriately applied to the above-mentioned transferred member. It is done to make it transfer.

  However, when the lubricant is supplied from the lubricant supply means to the surface of the image holding member after the toner image is transferred to the transfer member in this way, a member for supplying the lubricant to the surface of the image holding member is provided. There is a problem that it is necessary to provide the device, and the cost is high, and the apparatus is increased in size.

  Conventionally, as shown in Patent Document 2, the surface of the image holding member is charged by a charging roller that rotates in contact with the surface of the image holding member, and a lubricant is applied to the surface of the charging roller with a small pressure. In which the lubricant is supplied to the surface of the charging roller and the lubricant is applied from the charging roller to the surface of the image holding member.

  However, in this case, there is a problem that the lubricant is not properly supplied to the surface of the charging roller, or the lubricant supplied to the surface of the charging roller is not properly applied to the surface of the image holding member. .

  Conventionally, as disclosed in Patent Document 3, the linear velocity of the charging roller can be changed with respect to the linear velocity of the image holding member, and the linear velocity of the charging roller can be changed from the linear velocity of the image holding member during non-transfer. Proposals have been made to increase the speed and apply the lubricant to the image holding member.

  However, even in this case, there is still a problem that the lubricant is not properly supplied to the surface of the charging roller, and the lubricant cannot be appropriately applied from the charging roller to the surface of the image holding member. In this way, a mechanism for changing the linear velocity of the charging roller relative to the linear velocity of the image holding member is required, which increases the cost and increases the size of the apparatus, and further increases the linear velocity of the charging roller. In the case where the image holding member is made faster than the linear velocity of the image holding member, the surface of the image holding member is rubbed by the charging roller, and the surface of the image holding member is damaged or worn.

  Conventionally, as shown in Patent Document 4, the lubricant is scraped off by a rotating roller having a rough surface, and the lubricant scraped off by the rotating roller is applied from the rotating roller to the charging roller by the rotating brush roller. What has been proposed has been proposed.

However, even in this case, it is difficult to efficiently supply the lubricant to the charging roller, and it is necessary to provide a rotating roller or a rotating brush roller with a rough surface, which increases the cost and increases the cost. There was a problem of increasing the size.
JP 2006-259661 A JP-A-6-342234 JP-A-6-342236 JP-A-10-123900

  In the present invention, the surface of the image holding member is charged by a charging roller that rotates in contact with the surface of the image holding member, and a lubricant is supplied to the surface of the charging roller by a lubricant supply means, and the lubricant is charged. An object of the present invention is to solve the above-described problems in the image forming apparatus in which the roller is applied to the surface of the image holding member.

  That is, according to the present invention, in the image forming apparatus as described above, the lubricant is appropriately supplied to the surface of the charging roller and the lubricant is appropriately applied to the surface of the image holding member with a simple configuration. It is a problem to make.

  In the present invention, in order to solve the above-described problems, the surface of the image holding member is charged by a charging roller that rotates in contact with the surface of the image holding member, and the surface of the charging roller is supplied with a lubricant supply means. In an image forming apparatus in which a lubricant is supplied and the lubricant is applied from the charging roller to the surface of the image holding member, a surface layer made of an elastic material having irregularities is provided on the surface of the charging roller. .

  In the image forming apparatus, the lubricant supplied from the lubricant supply unit is stored in the concave portion of the unevenness provided on the surface layer of the charging roller, and the lubricant stored in the concave portion holds the image. It is applied to the surface of the member.

  Here, in the above-described image forming apparatus, the lubricant is sufficiently stored in the recesses in the unevenness provided on the surface layer of the charging roller, and the lubricant stored in the recesses is appropriately applied to the surface of the image holding member. In order to achieve this, the shape of the surface irregularities in the surface layer of the charging roller is higher than the inclination angle of the portion from the bottom of the concave portion toward the top of the convex portion in the rotation direction of the charging roller. It is preferable that the inclination angle of the portion from the top portion toward the bottom portion of the concave portion is large.

  Further, in the above image forming apparatus, the image holding member is held on the image holding member in order to prevent the surface of the image holding member from being rubbed by the charging roller to damage or wear the surface of the image holding member. It is preferable that the driven rotation is performed as the member moves.

  Further, it is preferable to provide an urging unit for pressing the lubricant against the charging roller so that the lubricant is appropriately supplied from the lubricant supplying unit to the charging roller.

  Further, in order to properly apply the lubricant supplied to the charging roller to the surface of the image holding member, the contact force between the charging roller and the image holding member is changed between the charging roller and the lubricant. It is preferable to make it stronger than the contact force.

  In the image forming apparatus of the present invention, the lubricant is supplied from the lubricant supply means to the surface of the charging roller, and the lubricant supplied to the surface of the charging roller is applied to the surface of the image holding member. Since the surface layer made of the elastic material having irregularities on the surface is provided, the lubricant supplied from the lubricant supplying means is accommodated in the recesses in the irregularities provided on the surface layer of the charging roller, and is accommodated in the recesses. The lubricant is applied to the surface of the image holding member.

  As a result, in the image forming apparatus of the present invention, the apparatus is not increased in size, and the lubricant is appropriately supplied to the surface of the charging roller with a simple configuration, and the lubricant is applied to the surface of the image holding member. In addition to being appropriately applied, it is possible to appropriately prevent the surface of the image holding member from being rubbed by the charging roller and being damaged or worn.

  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, the photosensitive drum 10 serving as an image holding member is rotated, contacts the surface of the photosensitive drum 10, and rotates with the photosensitive drum 10. The surface of the photosensitive drum 10 is charged by the charging roller 20 that is driven to rotate.

  Then, the surface of the photosensitive drum 10 thus charged is exposed according to the image data by the exposure device 11 to form an electrostatic latent image on the surface of the photosensitive drum 10, and thus the electrostatic latent image is formed. The toner is supplied from the developing device 12 to the photosensitive drum 10 on which the image is formed, and the electrostatic latent image formed on the surface of the photosensitive drum 10 is developed, and the electrostatic latent image is formed on the surface of the photosensitive drum 10. A corresponding toner image is formed.

  Next, the toner image formed on the surface of the photosensitive drum 10 in this way is guided to a position facing the transfer device 13, and the recording medium S is guided between the photosensitive drum 10 and the transfer device 13. The toner image formed on the surface of the photosensitive drum 10 by the transfer device 13 is transferred to the recording medium S, and the recording medium S on which the toner image is transferred in this way is guided to a fixing device (not shown). The image is fixed on the recording medium S.

  On the other hand, the cleaning blade 14 a provided in the cleaning device 14 is brought into contact with the surface of the photosensitive drum 10 after the toner image is transferred as described above, and remains on the surface of the photosensitive drum 10. Residues such as toner are removed from the surface of the photosensitive drum 10, and thereafter, the surface of the photosensitive drum 10 is charged by the charging roller 20 as described above.

Here, in the image forming apparatus according to this embodiment, as shown in FIGS. 1 and 2, as the charging roller 20, a surface layer 21 made of an elastic material having serrated irregularities on the surface thereof is provided. The formed one is used. In this embodiment, the shape of the irregularities in the surface layer 21 of the charging roller 20 is greater than the inclination angle θ _{1 of the} portion from the bottom of the concave portion 21a toward the top of the convex portion 21b in the rotation direction of the charging roller 20. the inclination angle theta ₂ of the portion towards the bottom of the recess 21a from the top of the convex portion 21b is large.

  When supplying the lubricant 31a to the surface of the charging roller 20 by the lubricant supplying means 30, as shown in FIG. 1, the solid lubricant 31 is applied to the charging roller 20 by an urging means 32 such as a spring. I try to press it against the surface. Examples of the material of the solid lubricant 31 include zinc stearate, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, Cadmium stearate, magnesium stearate, zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, copper oleate, zinc palmitate, cobalt palmitate, copper palmitate, palmitate Fatty acids such as magnesium, aluminum palmitate, calcium palmitate, zinc caprylate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricolinoneate, cadmium ricolinonenate Or metal salts, can be used colloidal hot silica powder or the like.

  When the charging roller 20 is driven and rotated as the photosensitive drum 10 rotates as described above, the convex portion 21a of the surface layer 21 provided on the surface of the charging roller 20 is deformed as shown in FIG. However, the lubricant 31 a is appropriately scraped off from the solid lubricant 31 pressed against the surface of the charging roller 20 by the convex portion 21 a and is accommodated in the concave portion 21 b of the surface layer 21.

  Then, the lubricant 31a is guided to the position in contact with the photosensitive drum 10 as the charging roller 20 rotates while being accommodated in the recess 21b in the surface layer 21 of the charging roller 20 as shown in FIG. As described above, the lubricant 31a is supplied from the concave portion 21b to the surface of the photosensitive drum 10, and the lubricant 31a supplied to the surface of the photosensitive drum 10 in this manner is the convex portion in the surface layer 21 of the charging roller 20. The lubricant 31a is appropriately applied to the surface of the photosensitive drum 10 by being pressed against the surface of the photosensitive drum 10 by 21a.

  Here, when the contact force between the charging roller 20 and the photosensitive drum 10 is made stronger than the contact force between the charging roller 20 and the solid lubricant 31, the concave portion of the charging roller 20 as described above. The lubricant 31 a accommodated in 21 b is appropriately supplied to the surface of the photosensitive drum 10, and the lubricant 31 a is more appropriately applied to the surface of the photosensitive drum 10.

  In forming the surface layer 21 made of the elastic material having serrated irregularities as described above on the surface of the charging roller 20, the irregularities are formed on the surface of the charging roller 20 as shown in FIG. In addition to the continuous formation in the axial direction, as shown in FIG. 6, the positions of the irregularities may be shifted at every axial interval of the charging roller 20, and further, the surface of the charging roller 20 is illustrated. However, it is also possible to provide the above irregularities in a scale shape.

1 is a schematic explanatory view showing an image forming apparatus according to an embodiment of the present invention. FIG. 6 is a partial explanatory view showing a state in which a surface layer made of an elastic material having sawtooth irregularities is provided on the surface of the charging roller in the image forming apparatus of the embodiment. 4 is a partial explanatory view showing a state in which the lubricant is scraped off from the solid lubricant by the charging roller in the image forming apparatus of the embodiment. FIG. FIG. 4 is a partial explanatory view showing a state in which a lubricant is applied to the surface of the photosensitive drum by supplying the lubricant from the charging roller to the surface of the photosensitive drum in the image forming apparatus of the embodiment. 3 is a schematic plan view of a charging roller in which unevenness is continuously formed in the axial direction of the charging roller in the image forming apparatus of the embodiment. FIG. FIG. 3 is a schematic plan view of a charging roller in which the positions of unevenness are shifted every required axial distance of the charging roller in the image forming apparatus of the embodiment.

Explanation of symbols

10 Photosensitive drum (image holding member)
DESCRIPTION OF SYMBOLS 11 Exposure apparatus 12 Developing apparatus 13 Transfer apparatus 14 Cleaning apparatus 14a Cleaning blade 20 Charging roller 21 Surface layer 21a Concavity 21b Convex part 30 Lubricant supply means 31 Solid lubricant 31a Lubricant 32 Energizing means S Recording medium θ ₁ Charging roller Inclination angle of the portion from the bottom of the concave portion toward the top of the convex portion toward the rotational direction θ ₂ Inclination angle of the portion from the top portion of the convex portion toward the bottom of the concave portion toward the rotational direction of the charging roller

Claims (6)

  The surface of the image holding member is charged by a charging roller that rotates in contact with the surface of the image holding member, and a lubricant is supplied to the surface of the charging roller by a lubricant supplying means, and the lubricant is image-held from the charging roller. An image forming apparatus provided on a surface of a member, wherein a surface layer made of an elastic material having irregularities is provided on the surface of the charging roller.   The image forming apparatus according to claim 1, wherein the lubricant supplied from the lubricant supply unit is accommodated in a recess in the unevenness provided in the surface layer of the charging roller, and the lubricant accommodated in the recess is an image. An image forming apparatus provided on a surface of a holding member.   3. The image forming apparatus according to claim 1, wherein the shape of the surface irregularities in the surface layer of the charging roller is a portion of the portion from the bottom of the concave portion toward the top of the convex portion in the rotation direction of the charging roller. An image forming apparatus, wherein an inclination angle from a top portion of a convex portion to a bottom portion of the concave portion is larger than the inclination angle.   4. The image forming apparatus according to claim 1, wherein the charging roller rotates following the movement of the image holding member. 5.   5. The image forming apparatus according to claim 1, wherein the lubricant supplying unit includes an urging unit that presses the lubricant against the charging roller. 6. apparatus.   6. The image forming apparatus according to claim 5, wherein a contact force between the charging roller and the image holding member is stronger than a contact force between the charging roller and the lubricant. Forming equipment.

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