JP2008003346A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that primarily transfers toner images from corresponding image carriers to a moving intermediate transfer body and then secondarily transfers the toner images to a recording medium from the intermediate transfer body by a secondary transfer device, the image forming apparatus being designed so as to prevent toner sticking to the parts between toner images transferred to the intermediate transfer body from being attached to the secondary transfer device. <P>SOLUTION: The image forming apparatus primarily transfers toner images formed on the corresponding image carriers 10 to the moving intermediate transfer body 20 and then guides the toner images to a position opposite to the secondary transfer device by the intermediate transfer body and secondarily transfers the toner images to a recording medium. In the image forming apparatus, an inter-image cleaning means 30 for removing toner sticking to the parts between the toner image transferred to the intermediate transfer body and the subsequent toner image is disposed in the downstream of the position of the primary transfer in the moving direction of the intermediate transfer body and between the positions of the secondary transfer and primary transfer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer, and in particular, primarily transfers a toner image formed on an image carrier to a moving intermediate transfer member, and transfers the toner image thus transferred to the intermediate transfer member. In the image forming apparatus that is guided to the position facing the secondary transfer device and secondary-transferred to the recording medium, the toner attached to the inter-image portion between the toner images transferred to the intermediate transfer body is This is characterized in that the intermediate transfer member is prevented from being applied to the secondary transfer device.

  Various types of image forming apparatuses such as copying machines and printers are used. In recent years, for example, an image forming apparatus that forms a full-color image as shown in FIG. 1 is known.

  Here, in this image forming apparatus, the image carrier 10 composed of four photosensitive drums corresponding to the four developing devices 11 containing toners of different colors of yellow, magenta, cyan and black. Is provided.

  When a full color image using each color toner is formed by this image forming apparatus, each image carrier 10 is rotated and the outer peripheral surface of each image carrier 10 is charged by the charging device 12. The image carrier 10 thus charged is exposed according to the image data by the exposure device 13 to form an electrostatic latent image on the outer peripheral surface of each image carrier 10. Each developing device 11 supplies toner of a predetermined color to each image carrier 10 and performs development, and forms a toner image of each color on the outer peripheral surface of each image carrier 10.

  Next, the toner images of the respective colors formed on the respective image carriers 10 are respectively transferred to the intermediate transfer member 20 composed of an intermediate transfer belt that is driven around the roller 21 and formed into a roller shape. 22 is sequentially transferred to form a full-color toner image on the intermediate transfer member 20, while the toner remaining on the outer peripheral surface of each image carrier 10 after transfer is transferred to the first cleaning device. 14 from the outer peripheral surface of each image carrier 10.

  Then, the full-color toner image formed on the intermediate transfer member 20 as described above is guided to a position facing the secondary transfer device 23 formed into a roller shape by the intermediate transfer member 20, and the image forming apparatus. The sheet-like recording medium S accommodated in the lower part of the sheet is guided between the intermediate transfer member 20 and the secondary transfer device 23 by the feed roller 15 and formed on the intermediate transfer member 20 by the secondary transfer device 23 described above. The resulting 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 in this way is guided to the fixing device 16, and the transferred full-color toner image is fixed on the recording medium S and discharged, while being transferred to the recording medium S. The toner remaining on the intermediate transfer member 20 without being removed is removed from the intermediate transfer member 20 by the second cleaning device 17.

  Here, as described above, the toner images are sequentially transferred from the image carriers 10 to the intermediate transfer member 20 in order, and the toner images thus transferred are sequentially transferred onto the recording medium S by the secondary transfer device 23. In the case where the image forming operation by the secondary transfer is continuously performed, the portion between the images between the toner image primarily transferred to the intermediate transfer body 20 and the toner image to be transferred next is reversed. Charged toner, weakly charged toner, or the like may adhere, and a pattern image for adjusting image forming conditions may be formed in such a portion between images.

  Then, when a reversely charged toner, a weakly charged toner, or the like adheres to the portion between the toner images transferred to the intermediate transfer body 20 in this way, or a pattern image for adjusting image forming conditions is formed. The toner in the inter-image portion is not transferred to the recording medium S, but is applied to the roller-shaped secondary transfer device 23. The secondary transfer device 23 is contaminated with toner, and thus the secondary transfer is performed. There is a problem in that the toner applied to the apparatus 23 adheres to the back surface of the recording medium S that has been guided next, causing back stains, and secondary transfer cannot be performed properly.

  Further, conventionally, after a toner image is formed by supplying toner from a developing device to an image carrier composed of a photosensitive drum, before the toner image is transferred from the image carrier to a transfer drum, the image carrier There has been proposed an image forming apparatus in which a second blade is brought into contact with a non-image area to remove toner adhering to the non-image area (see, for example, Patent Document 1).

However, in the above-described image forming apparatus, the toner adhering to both ends of the image carrier on which the toner image is not formed is removed by the second blade, and the image between the toner image and the next toner image is removed. The toner adhering to the intermediate portion is not removed, and the above-described problems in the image forming apparatus cannot be solved.
JP-A-5-313441

  According to the present invention, a toner image formed on an image carrier is primarily transferred to a moving intermediate transfer member, and the toner image thus transferred is guided to a position facing a secondary transfer device by the intermediate transfer member. An object of the present invention is to solve the above-described problems in an image forming apparatus that is secondarily transferred to a medium.

  That is, according to the present invention, in the image forming apparatus as described above, the toner attached to the inter-image portion between the toner images transferred to the intermediate transfer member is prevented from being applied to the secondary transfer apparatus. It is an object of the present invention to prevent the back surface of the recording medium from being stained by the toner applied to the toner image and from being unable to perform transfer appropriately.

  In the present invention, in order to solve the above problems, the toner image formed on the image carrier is primarily transferred to the moving intermediate transfer member, and the toner image thus transferred is secondarily transferred by the intermediate transfer member. In the image forming apparatus that is guided to a position facing the transfer device and secondarily transferred to the recording medium, the second transfer position is located downstream of the first transfer position in the moving direction of the intermediate transfer body. In the meantime, an inter-image cleaning unit is provided for removing toner adhering to an inter-image portion between the toner image transferred to the intermediate transfer member and the next toner image from the intermediate transfer member.

  In the image forming apparatus according to the present invention, when the above-described inter-image cleaning unit is provided, for example, between the above-described primary transfer position and the secondary transfer position on the downstream side in the moving direction of the intermediate transfer member. A cleaning member is provided, and the cleaning member is brought into contact with and separated from the intermediate transfer member so that the toner adhering to the portion between the images is removed from the intermediate transfer member only while the cleaning member is removed from the intermediate transfer member. A control means is provided, or a recovery voltage applying means for applying a toner recovery voltage to the cleaning member only while removing the toner adhering to the inter-image portion from the intermediate transfer member. can do.

  Here, when the recovery voltage is applied to the cleaning member as described above to remove the toner adhering to the inter-image portion from the intermediate transfer member, the cleaning member is brought into contact with the intermediate transfer member and the toner is intermediated. Compared with the case of removing from the transfer body, the load applied to the intermediate transfer belt is greatly reduced. Therefore, when the recovery voltage is applied to the cleaning member from the recovery voltage applying unit as described above to remove the toner adhering to the inter-image portion from the intermediate transfer body, the next formed on the image carrier The toner image may be adversely affected even when the toner image is primarily transferred to the intermediate transfer member or when the previous toner image transferred to the intermediate transfer member is secondarily transferred to the recording medium. It is suppressed.

  In addition, when the toner adhered to the inter-image portion is removed from the intermediate transfer member by the above-described inter-image cleaning unit, the toner adhered to the inter-image portion is easily removed so that the toner adhered to the inter-image portion is easily removed. It is preferable to provide a charge control means for controlling the charge of the toner adhering to the inter-image portion at a position upstream of the intermediate transfer member in the moving direction from the position where the toner is removed by the image-cleaning means.

  Further, when the toner adhered to the inter-image portion is removed from the intermediate transfer member by the inter-image cleaning unit as described above, the interval between the image portions between the toner image transferred to the intermediate transfer member and the next toner image. Is preferably increased by the image interval control means.

  In the image forming apparatus according to the present invention, the toner image transferred in this way on the downstream side in the moving direction of the intermediate transfer member from the position where the toner image formed on the image carrier is primarily transferred to the intermediate transfer member as described above. Is provided between the intermediate transfer member and the position where the toner image is secondarily transferred from the intermediate transfer member to the recording medium, and the toner image transferred to the intermediate transfer member and the next transferred toner image are provided by the inter-image cleaning member. Since the toner adhering to the inter-image portion is removed from the intermediate transfer member, the toner adhering to the inter-image portion is prevented from being applied to the secondary transfer device.

  As a result, in the image forming apparatus of the present invention, the toner applied to the secondary transfer device is prevented from smearing the back surface of the recording medium or adversely affecting the secondary transfer, and good image formation can be performed. It becomes like this.

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

  As shown in FIG. 2, the image forming apparatus according to this embodiment also has four toners containing different colors of yellow, magenta, cyan, and black as in the image forming apparatus shown in FIG. Corresponding to the developing device 11, an image carrier 10 including four photosensitive drums is provided.

  When forming a full-color image in this image forming apparatus, as in the case described above, each image carrier 10 is rotated and the outer peripheral surface of each image carrier 10 is charged by the charging device 12. The image carrier 10 thus charged is exposed according to the image data by the exposure device 13 to form an electrostatic latent image on the outer peripheral surface of each image carrier 10. Each developing device 11 supplies toner of a predetermined color to each image carrier 10 and performs development, and forms a toner image of each color on the outer peripheral surface of each image carrier 10.

  Next, the toner images of the respective colors formed on the respective image carriers 10 are respectively transferred to the intermediate transfer member 20 composed of an intermediate transfer belt that is driven around the roller 21 and formed into a roller shape. 22 is sequentially transferred to form a full-color toner image on the intermediate transfer member 20, while the toner remaining on the outer peripheral surface of each image carrier 10 after transfer is transferred to the first cleaning device. 14 from the outer peripheral surface of each image carrier 10.

  Then, the full-color toner image formed on the intermediate transfer member 20 as described above is guided to a position facing the secondary transfer device 23 formed into a roller shape by the intermediate transfer member 20, and the image forming apparatus. The sheet-like recording medium S accommodated in the lower part of the sheet is guided between the intermediate transfer member 20 and the secondary transfer device 23 by the feed roller 15 and formed on the intermediate transfer member 20 by the secondary transfer device 23 described above. The resulting 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 in this way is guided to the fixing device 16, and the transferred full-color toner image is fixed on the recording medium S and discharged, while being transferred to the recording medium S. The toner remaining on the intermediate transfer member 20 without being removed is removed from the intermediate transfer member 20 by the second cleaning device 17.

  Here, in the image forming apparatus in this embodiment, the primary transfer is performed in this way on the downstream side in the moving direction of the intermediate transfer body 20 from the position where the toner image is primarily transferred from each image carrier 10 to the intermediate transfer body 20. An inter-image cleaning means 30 is provided so as to face the roller 21 a between the intermediate transfer body 20 and the position where the toner image is secondarily transferred to the recording medium S. By the inter-image cleaning means 30, the intermediate transfer body 20 The toner adhering to the portion between the images between the toner image transferred to the next toner image and the next toner image is removed.

  Then, when the toner adhering to the inter-image portion between the toner image transferred to the intermediate transfer member 20 by the inter-image cleaning unit 30 and the next toner image is removed, the inter-image portion of the intermediate transfer member 20 is removed. The toner adhering to the recording medium S is prevented from being applied to the secondary transfer device 23. Next, the back surface of the recording medium S guided between the intermediate transfer body 20 and the secondary transfer device 23 is stained with toner, The secondary transfer is also prevented from being adversely affected.

  Here, in the image forming apparatus in this embodiment, as shown in FIGS. 3A and 3B, a plate-like cleaning blade 32 is used as a cleaning member in the cleaning device 31 as the above-described inter-image cleaning means 30. The cleaning device 31 is provided at a position facing the roller 21a, and the cleaning device 31 is used as a control means for contacting and separating the cleaning blade 31a from the intermediate transfer member 20. A moving device 41 for reciprocating relative to 20 is provided.

  In the state where the toner adhering to the inter-image portion of the intermediate transfer member 20 is not removed in the inter-image cleaning unit 30, the cleaning device 31 is moved to the intermediate transfer by the moving device 41 as shown in FIG. The cleaning blade 32 provided in the cleaning device 31 is separated from the body 20 so as not to contact the intermediate transfer body 20, and the toner image primarily transferred to the intermediate transfer body 20 is not removed by the cleaning blade 32. To do. On the other hand, when removing the toner adhering to the inter-image portion of the intermediate transfer member 20, the cleaning device 31 is moved toward the intermediate transfer member 20 by the moving device 41 as shown in FIG. The cleaning blade 32 is brought into contact with the intermediate transfer member 20 so that the toner adhering to the portion between the images is removed by the cleaning blade 32.

  The inter-image cleaning unit 30 used in the above-described image forming apparatus is not limited to this.

  For example, in the above-described inter-image cleaning means 30, the cleaning device 32 is moved by the moving device 41 so that the cleaning blade 31 is brought into contact with or separated from the intermediate transfer body 20. It is also possible to move only the above-mentioned cleaning blade 31 by means of (not shown) so that the cleaning blade 31 contacts and separates from the intermediate transfer member 20.

  Further, in the above-described image cleaning means 30, when the plate-shaped cleaning blade 31 is brought into contact with the intermediate transfer member 20 to remove the toner adhering to the inter-image portion, as shown in FIG. A neutralizing brush roller 51 is provided as a charge control means for controlling the charging of the toner adhering to the portion between the images at a position upstream of the moving direction of the intermediate transfer member 20, and the intermediate transfer member 20 is provided by the neutralizing brush roller 51. It is also possible to eliminate the toner adhering to the portion between the images.

  When the toner adhering to the inter-image portion of the intermediate transfer member 20 is neutralized by the neutralizing brush roller 51 as described above, the adhesion force of the toner to the intermediate transfer member 20 is reduced, and the cleaning blade 31 is moved to the intermediate transfer member. Even when the contact pressure to be brought into contact with the toner 20 is lowered, the toner adhering to the intermediate transfer member 20 is appropriately removed. As a result, the load on the intermediate transfer member 20 due to the contact of the cleaning blade 31 is reduced, and the influence on the primary transfer and the secondary transfer is reduced.

  In the above-described image cleaning means 30, a plate-like cleaning blade 31 is used as a cleaning member. However, as shown in FIG. 5, a rotating brush roller 33 is used as the cleaning member, and this brush roller 33 is used. Thus, it is possible to collect the toner adhering to the inter-image portion of the intermediate transfer body 20 and to remove the collected toner from the brush roller 33 by the scraping member 34.

  Further, as shown in FIG. 6, a long sheet material 35 wound up in a roll shape is used as the cleaning unit 30 between the images, and the sheet material 35 is brought into contact with the intermediate transfer member 20. As the control means for separating, a member in which the pressing member 42 is reciprocated by the cylinder 43 and the spring 44 is used, and the sheet material 35 is wound around the winding member 36 through the pressing member 42. It is also possible to do.

  When the toner adhering to the inter-image portion of the intermediate transfer body 20 is removed by the inter-image cleaning means 30, the pressing member 42 is moved toward the intermediate transfer body 20 against the spring 44 by the cylinder 43. The pressing member 42 brings the sheet material 35 into contact with the intermediate transfer member 20 to remove the toner adhering to the portion between the images. The sheet material 35 thus adhering the toner is removed from the winding roller. Take up around 36.

  Further, as shown in FIG. 7, a conductive collection roller 37 is used as a cleaning member as the above-described image cleaning means 30, and the collection roller 37 is moved with respect to the intermediate transfer member 20, and the toner. As a collecting voltage applying means for applying the collecting voltage, it is possible to apply a voltage having a polarity opposite to that of the toner from the collecting power supply 61 to the collecting roller 37.

  When the toner adhering to the inter-image portion of the intermediate transfer member 20 is removed by the inter-image cleaning unit 30, the recovery roller 37 is brought close to or in contact with the intermediate transfer member 20, and the above-described recovery is performed. A voltage having a polarity opposite to that of the toner is applied from the power supply 61 to the collecting roller 37 to collect the toner adhering to the portion between the images of the intermediate transfer member 20, and the toner collected on the collecting roller 37 is scraped off. To remove from the collection roller 37. When the toner having the polarity opposite to the charging polarity of the toner is applied to the collecting roller 37 from the collecting power source 51 to collect the toner adhering to the portion between the images of the intermediate transfer member 20, the collecting is performed. The load on the intermediate transfer member 20 at the time is reduced, and the influence on the primary transfer and the secondary transfer is reduced.

  Further, when the toner having a polarity opposite to that of the toner is applied from the recovery power source 61 to the recovery roller 37 in this way to recover the toner adhering to the portion between the images of the intermediate transfer member 20, as shown in FIG. A charging device 52 is provided as a charge control means for controlling the charging of the toner adhering to the portion between the images at a position upstream of the collection roller 37 in the moving direction of the intermediate transfer member 20, and the charging device 52 has a charging power supply 53. Therefore, it is also possible to apply a voltage having the same polarity as the charging polarity of the toner to appropriately charge the reversely charged toner or the weakly charged toner adhering to the portion between the images of the intermediate transfer body 20.

  Then, when the reversely charged toner or the weakly charged toner adhering to the portion between the images of the intermediate transfer member 20 is appropriately charged by the charging device 52, the toner applies a voltage having a polarity opposite to the charged polarity of the toner. The collected rollers 37 are appropriately collected. Although not shown, a conductive brush roller or the like may be used instead of the collection roller 37 described above. Further, a voltage having a polarity opposite to that at the time of recovery is applied from the recovery power source 51 to the recovery roller 37 at an appropriate time, and the toner recovered by the recovery roller 37 as described above is returned to the intermediate transfer member 20. The secondary transfer device 23 may be separated from the intermediate transfer member 20, and the toner returned to the intermediate transfer member 20 may be removed from the intermediate transfer member 20 by the second cleaning device 17.

  In the image forming apparatus, as described above, the operation for removing the toner adhering to the inter-image portion between the toner image transferred to the intermediate transfer body 20 by the inter-image cleaning unit 30 and the next toner image. However, it is possible to remove the toner adhering to the portion between the images only at an appropriate time according to various image forming conditions such as environmental conditions. However, when a pattern image for adjusting image forming conditions is formed in a portion between images between the toner image primarily transferred to the intermediate transfer body 20 and the next toner image, a large amount of toner is imaged. In this case, the toner adhered to the inter-image portion is always removed by the above-described inter-image cleaning means 30.

  Further, when the toner adhering to the portion between the images between the toner image primarily transferred to the intermediate transfer body 20 and the next toner image as described above is removed, the influence on the primary transfer and the secondary transfer described above is affected. In order to reduce this, it is preferable to delay the primary transfer timing and increase the interval between the toner images and the next toner image.

It is a schematic explanatory drawing of the conventional image forming apparatus. 1 is a schematic explanatory diagram of an image forming apparatus according to an embodiment of the present invention. An example of the inter-image cleaning unit provided in the image forming apparatus in the above embodiment is shown in which the cleaning device is moved and the cleaning blade provided in the cleaning device is separated from the intermediate transfer member, and the intermediate transfer member It is the schematic explanatory drawing which showed the state made to contact. FIG. 5 is a schematic explanatory diagram illustrating a state in which toner attached to an inter-image portion of an intermediate transfer member is removed in a first modification of the inter-image cleaning unit provided in the image forming apparatus in the embodiment. FIG. 10 is a schematic explanatory diagram showing a state in which toner attached to an inter-image portion of an intermediate transfer member is removed in a second modification of the inter-image cleaning unit provided in the image forming apparatus in the above embodiment. FIG. 10 is a schematic explanatory diagram illustrating a state in which toner attached to an inter-image portion of an intermediate transfer member is removed in a third modification of the inter-image cleaning unit provided in the image forming apparatus in the embodiment. FIG. 10 is a schematic explanatory diagram illustrating a state in which toner attached to an inter-image portion of an intermediate transfer member is removed in a fourth modification of the inter-image cleaning unit provided in the image forming apparatus in the embodiment. FIG. 10 is a schematic explanatory diagram illustrating a state in which toner attached to an inter-image portion of an intermediate transfer member is removed in a fifth modification of the inter-image cleaning unit provided in the image forming apparatus in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image carrier 11 Developing device 12 Charging device 13 Exposure device 14 First cleaning device 15 Feed roller 16 Fixing device 17 Second cleaning device 20 Intermediate transfer member 21, 21a Roller 22 Primary transfer device 23 Secondary transfer device 30 Inter-image cleaning Means 31 Cleaning device 32 Cleaning blade 33 Brush roller 34 Scraping member 35 Sheet material 36 Winding roller 37 Recovery roller 38 Scraping member 41 Moving device 42 Pressing member 43 Spring 51 Static electricity removing brush roller 52 Charging device 53 Charging power source 61 For recovery Power supply

Claims (5)

  The toner image formed on the image carrier is primarily transferred to a moving intermediate transfer member, and the toner image thus transferred is guided to a position opposite to the secondary transfer device by the intermediate transfer member, and is then transferred to the recording medium. In the image forming apparatus to be transferred, the toner image transferred to the intermediate transfer body between the primary transfer position and the secondary transfer position downstream of the intermediate transfer body in the moving direction. An image forming apparatus, comprising: an inter-image cleaning unit that removes toner adhering to an inter-image portion between a next toner image from an intermediate transfer member.   2. The image forming apparatus according to claim 1, wherein a cleaning member is provided between the primary transfer position and the secondary transfer position on the downstream side in the moving direction of the intermediate transfer body from the primary transfer position. In addition, there is provided control means for bringing the cleaning member into contact with and separating from the intermediate transfer member so that the toner adhering to the portion between the images is removed from the intermediate transfer member only during removal of the toner from the intermediate transfer member. An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein a cleaning member is provided between the primary transfer position and the secondary transfer position on the downstream side in the moving direction of the intermediate transfer body from the primary transfer position. In addition, an image forming apparatus comprising: a collecting voltage applying unit that applies a toner collecting voltage to the cleaning member only while the toner adhering to the portion between the images is removed from the intermediate transfer member.   4. The image forming apparatus according to claim 1, wherein the intermediate transfer member is positioned upstream of the position where the toner adhered to the inter-image portion is removed by the inter-image cleaning unit. In addition, an image forming apparatus is provided with charge control means for controlling charging of the toner adhering to a portion between the images.   5. The image forming apparatus according to claim 1, wherein when the toner adhered to the inter-image portion is removed from the intermediate transfer member by the inter-image cleaning unit, the toner is transferred to the intermediate transfer member. An image forming apparatus comprising an image interval control means for increasing an interval between image portions between a toner image and a next toner image.

Images