JP2006184885A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve freedom of layout of an intermediate transfer body cleaning device and reduce the size and cost of an image forming apparatus by miniaturizing the cleaning device. <P>SOLUTION: A blush member 41 of the intermediate transfer body cleaning device 40 is separated from a transfer belt 7 during image formation. To clean the intermediate transfer belt 7, the brush member 41 of the intermediate transfer body cleaning device 40 is brought into firm contact with the transfer belt 7 and cleans off toner remaining on the transfer belt 7. In this case, when a high voltage is applied to a cleaning roller 42 from a high voltage power source 46, a voltage is also applied to the brush member 41 disposed in contact with the cleaning roller 42, so that residual toner on the intermediate transfer belt 7 is removed by the brush member 41. Thereafter, the substance sticking on the brush member 41 is recovered by the cleaning roller 42. This improves cleaning effect. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that forms a color image by superimposing a plurality of color toner images via an intermediate transfer member.

  In an electrophotographic image forming apparatus, a charger, an exposure device, a developing device, a transfer device, a cleaning device, and the like are provided around a photosensitive drum as an image carrier. A fixing device is provided on the downstream side of the transfer material of the photosensitive drum. In such an image forming apparatus, first, the surface of the photosensitive drum is uniformly charged by the charger. Thereafter, based on the image information, the photosensitive drum is exposed by the exposure device, and an electrostatic latent image is formed on the surface of the photosensitive drum. This electrostatic latent image is developed by a developing device. Here, in the case of a full image forming apparatus, there are provided four developing units for accommodating cyan developer, magenta developer, yellow developer, and black developer, respectively, and four colors of cyan, magenta, yellow, and black, respectively. Development is performed. Further, in an image forming apparatus having an intermediate transfer belt, the four colors of cyan, magenta, yellow, and black developed on the surface of the photosensitive drum are temporarily transferred to the intermediate transfer belt, respectively, via the intermediate transfer belt. Transferred onto transfer paper. Thereafter, the transfer sheet on which the toner image is formed is fixed by the fixing device through the conveyance path and is discharged to the discharge unit.

  Thereafter, residual toner remaining on the surface of the photosensitive drum and the surface of the intermediate transfer belt is cleaned by a cleaning unit. Here, in order to improve the image quality of the formed image, a method of separating the cleaning device from the photoconductor when forming an image on the photoconductor has been proposed (Patent Document 1).

In addition, when the cleaning of the predetermined area of the intermediate transfer belt is completed, the intermediate transfer belt cleaning device is separated from the intermediate transfer belt, and the aggregated toner on the edge of the cleaning blade is broken by the impact at the time of separation to increase the cleaning effect. Has also been proposed (Patent Document 2).
JP 7-84494 A JP-A-8-63071

  In recent years, along with an increase in personal use of full image forming apparatuses, there has been a demand for downsizing and cost reduction of image forming apparatuses. In order to reduce the size of the image forming apparatus, it is necessary to reduce the arrangement space of each component, and the degree of freedom of layout of each component is limited.

  However, in the techniques described in Patent Documents 1 and 2, it is necessary to separate the entire cleaning device from the photosensitive member or the intermediate transfer belt, and the mechanism for that purpose becomes large. Therefore, the arrangement position of the cleaning device is limited, and it is difficult to reduce the size of the entire image forming apparatus.

  An object of the present invention is to improve the degree of freedom of the layout of the cleaning device by reducing the size of the intermediate transfer member cleaning device, and to reduce the size and cost of the image forming apparatus.

  The image forming apparatus according to a first aspect includes an image carrier, a developing device, an intermediate transfer member, and an intermediate transfer member cleaning device. Here, the image carrier is for forming an electrostatic latent image on the surface. The developing device is for developing the electrostatic latent image on the surface of the image carrier. The intermediate transfer member is disposed to face the image carrier, and is for transferring a toner image formed on the image carrier. The sheet conveyance path is for conveying a sheet on which a toner image is formed. The intermediate transfer body cleaning device is for cleaning the intermediate transfer body, and is arranged so as to be pressed against and separated from the transfer body, and is rotatable, and a brush member for cleaning the surface of the transfer body. A cleaning roller that frictionally contacts the brush member and electrically adsorbs toner adhering to the brush member.

  Here, since the brush member provided in the cleaning device is disposed so as to be able to press and separate from the intermediate transfer member, it is necessary to press or separate the entire cleaning device from the intermediate transfer member when cleaning the intermediate transfer member. There is no. Therefore, compared to the case where the entire cleaning device is separated from or pressed against the intermediate transfer member, the intermediate transfer member cleaning device can be reduced in size, improving the degree of freedom of the layout of the cleaning device and reducing the size of the image forming apparatus. And cost reduction.

  The image forming apparatus according to a second aspect is the apparatus according to the first aspect, wherein the cleaning roller is disposed above the brush member. Also, a swing mechanism that swings the brush member with the cleaning roller shaft as a fulcrum, and a blade that is disposed on the side of the cleaning roller and whose tip is pressed against the surface of the cleaning roller to remove deposits on the surface of the cleaning roller. It has more.

  In this apparatus, when cleaning the residual toner or the like attached to the intermediate transfer member by the brush member, it is necessary to press the brush member against the intermediate transfer member and to separate the brush member from the intermediate transfer member after the cleaning is completed. Therefore, the cleaning roller is disposed above the brush member, the brush member is swung with the shaft of the cleaning roller as a fulcrum, and the brush member is pressed against or separated from the intermediate transfer member. Therefore, the brush member can be pressed against or separated from the intermediate transfer member with a simple structure. In addition, by adhering the tip of the blade to the surface of the cleaning roller, deposits on the surface of the cleaning roller can be removed.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the blade is disposed such that an angle formed with the horizontal line is equal to or greater than a repose angle of the toner.

  Here, since the angle formed by the blade and the horizontal line is equal to or greater than the repose angle of the toner, the toner scraped off by the blade falls without collecting on the blade.

  An image forming apparatus according to a fourth aspect of the present invention is the apparatus according to the third aspect, further comprising a recovery spiral disposed below the blade for recovering the deposits removed by the blade, and the center of the brush member A line connecting the center of the cleaning roller and the center of the collection spiral forms a triangle.

  In this apparatus, a collection spiral is provided below the blade, and the deposits removed from the blade are collected. Here, since the line connecting the center of the brush member, the center of the cleaning roller, and the center of the collection spiral is a triangle, the space of the cleaning device can be saved.

  An image forming apparatus according to a fifth aspect is the apparatus according to the second aspect, wherein the intermediate transfer member is an intermediate transfer belt supported by a plurality of support rollers, and the swing mechanism is opposed to the shaft of the brush member. An eccentric cam provided rotatably at the end of the shaft of the support roller, a cam receiving portion provided at the end of the shaft of the brush member and in contact with the eccentric cam, and the brush member as an intermediate transfer belt And a biasing member that biases to the side. Here, the brush member is swung by the contact between the eccentric cam and the cam receiving portion, and the brush member can be pressed against and separated from the intermediate transfer belt.

  In this apparatus, during the image formation, the large diameter portion of the eccentric cam abuts on a cam receiving portion provided on the shaft of the brush member. Accordingly, the distance between the shaft of the support roller and the shaft of the brush member is increased, and the intermediate transfer belt and the brush member are separated from each other. On the other hand, when the intermediate transfer belt is cleaned, the small-diameter portion of the eccentric cam comes into contact with a cam receiving portion provided on the shaft of the brush member. Therefore, the distance between the shaft of the support roller and the shaft of the brush member is reduced, the brush member is pressed against the intermediate transfer belt, and the intermediate transfer belt can be cleaned by the brush member.

  An image forming apparatus according to a sixth aspect is the apparatus according to any one of the first to fifth aspects, wherein the image carrier is a rotatable photosensitive drum. The developing device is disposed adjacent to the photosensitive drum, and is provided corresponding to a rotating frame that rotates about an axis parallel to the rotating shaft of the photosensitive drum, and corresponding to a plurality of colors of toner, and each is held by the rotating frame. And a plurality of developing devices. The intermediate transfer body cleaning device is disposed in a substantially triangular space formed between the rotary frame body, the intermediate transfer body, and the sheet conveyance path.

  In this apparatus, a rotary developing device having a rotating frame body is employed, and a substantially triangular space is formed between the rotating frame body, the intermediate transfer body, and the sheet conveyance path. By providing an intermediate transfer body cleaning device having a substantially triangular shape in the substantially triangular space, a limited dead space can be used effectively, and the overall size of the image forming apparatus can be reduced. it can.

  An intermediate transfer member cleaning device according to a seventh aspect is a cleaning device for cleaning the intermediate transfer member of the image forming apparatus, and includes a brush member, a cleaning roller, a blade, and a collection spiral. Here, the brush member is rotatable with respect to the intermediate transfer member of the image forming apparatus, and is for cleaning the surface of the intermediate transfer member. The cleaning roller is disposed above the brush member, and is used for adsorbing toner adhering to the brush member by frictional contact with the brush member. The blade is disposed on the side of the cleaning roller, and its tip is pressed against the surface of the cleaning roller to remove deposits on the surface of the cleaning roller. The collection spiral is disposed below the blade and is for collecting deposits removed by the blade.

  Conventionally, as a means for cleaning the intermediate transfer member, a structure in which a blade or a cleaning roller is directly pressed against the intermediate transfer member has been adopted. However, when a transfer belt is used as an intermediate transfer member, for example, when the blade or the cleaning roller is pressed or separated, the load on the belt fluctuates, the linear velocity of the belt fluctuates, and a defect occurs in the formed image. There was a problem.

  Here, since it is the brush member that is pressed against and separated from the intermediate transfer member, the load fluctuation on the intermediate transfer member is small. Therefore, even when a transfer belt is used as the intermediate transfer member, when the brush member is pressed and separated, the load fluctuation on the belt is small, and the image quality of the formed image can be improved.

  The invention according to claim 8 is the intermediate transfer member cleaning according to claim 7, further comprising a voltage applying device. Here, the voltage application device is for applying a high voltage to the cleaning roller in order to electrically adsorb the toner adhering to the brush member.

  Here, the toner adhering to the brush member can be efficiently adsorbed by applying a high voltage.

  In the present invention, in the image forming apparatus, the brush member provided in the cleaning device is disposed so as to be able to press and separate from the intermediate transfer member. Therefore, when cleaning the intermediate transfer member, the entire cleaning device is moved to the intermediate transfer member. There is no need for pressure contact or separation. Therefore, compared with the case where the entire cleaning device is separated or pressed against the intermediate transfer member, the intermediate transfer member cleaning device can be reduced in size, and the layout degree of the cleaning device can be improved and the image forming apparatus can be reduced in size. And cost reduction.

  In addition, in an image forming apparatus employing a rotary developing device having a rotating frame body, a substantially triangular space formed between the rotating frame body, the intermediate transfer body, and the paper conveyance path has a substantially triangular shape. By providing the intermediate transfer member cleaning device, the limited dead space can be used effectively.

  FIG. 1 shows a color printer 1 as an image forming apparatus according to an embodiment of the present invention. FIG. 1 is a schematic diagram for showing the arrangement of each component, and details of each part are omitted.

[overall structure]
The color printer 1 is connected to a computer (not shown) or the like, and is a device that can print a color image on paper based on image information sent from the computer or the like. In the color printer 1, the right side in FIG. 1 is the side operated by the operator, and in the following, the right side of the apparatus in FIG. 1 is the front side and the left side is the back side.

  The color printer 1 includes a photosensitive drum 2, a rotary developing device 3, a laser unit 4, a toner container 5, a toner supply device 6, an intermediate transfer belt 7, a secondary transfer roller 8, and a fixing device 9. And have.

[Photosensitive drum]
The photosensitive drum 2 has an electrostatic latent image formed on the surface thereof, and is rotatably provided in the center of the apparatus. The rotation axis of the photosensitive drum 2 extends in the lateral direction as viewed from the front side of the apparatus. It is provided so as to extend perpendicular to the paper surface of FIG. A charging roller 10 for uniformly charging the surface of the photosensitive drum 2 is provided above the photosensitive drum 2. Further, a drum cleaning device 11 for cleaning the toner and adhering matter remaining on the surface of the photosensitive drum 2 is provided on the side of the photosensitive drum 2.

[Rotating development device]
The rotary developing device 3 develops the electrostatic latent image formed on the photosensitive drum 2 with toner of each color, and is adjacent to the photosensitive drum 2 and has a center substantially the same as the center of the photosensitive drum 2. It is provided so that it may become a position. The rotary developing device 3 includes a rotary frame 15 and four developing units 16 provided corresponding to the four color toners and supported by the rotary frame 15. The rotary frame 15 has a cylindrical shape that is rotatable around an axis parallel to the rotation axis of the photosensitive drum 2 and is rotated by a drive mechanism including a motor and a gear (not shown).

  As shown in FIG. 1, the rotary frame 15 has four sections that are divided into four equal parts in the circumferential direction by a partition frame that extends radially from the center of the rotation axis, and each section has yellow, cyan, Developers 16 corresponding to four toner colors of magenta and black are arranged. Each developing device 16 has substantially the same configuration, and is provided with a developing roller 70 that can be disposed to face the photosensitive drum 2, a sliding roller 71, a stirring roller 72 for stirring toner, and the like.

[Laser unit]
The laser unit 4 scans and exposes the photosensitive drum 2 based on image information sent from an external computer or the like. The laser unit 4 is provided above the photosensitive drum 2 and from the rotary shaft of the rotary developing device 3. It is arranged on the back side. Precisely, the front end of the laser unit 4 (the end on the side from which the laser beam is emitted) is located almost directly above the rotation axis of the rotary developing device 3, and is inclined downward as it goes to the rear end side. The end is located below the upper end of the rotary developing device 3. The internal configuration of the laser unit 4 is the same as the conventional configuration, and includes a laser light source, a polygon mirror, a polygon mirror driving motor, and the like. In addition, a reflection mirror 20 is provided in front of the laser light path of the laser unit 4. Therefore, as indicated by a one-dot chain line in FIG. 1, the laser light emitted from the laser unit 4 is bent by the reflection mirror 20 and passes above the front side of the rotary developing device 3, and the surface of the photosensitive drum 2. It comes to be irradiated.

[Toner container]
The toner accommodating portion 5 is a portion that accommodates toner to be supplied to each developing device 16 of the rotary developing device 3 and is located above the photosensitive drum 2 and on the side facing the laser unit 4 (the front side of the device). Has been placed. The toner storage unit 5 includes four storage units that store toner of each color of yellow, cyan, magenta, and black, which are arranged side by side in the horizontal direction (the vertical direction in FIG. 1). Further, the toner storage portion 5 can be taken out to the front side of the apparatus.

[Toner supply device]
The toner supply device 6 is for supplying the toner of each color stored in the toner storage unit 5 to the corresponding developing device 16, and above the photosensitive drum 2, the laser unit 4, the toner storage unit 5, and the like. Is arranged in the space between. As shown in FIG. 1, the toner supply device 6 includes four toner supply pipes 25 that are movable in the vertical direction, and a toner supply pipe 25 that corresponds to a portion of the toner storage unit 5 that stores toner of each color. And a drive mechanism (not shown) for moving each toner supply pipe 25 up and down.

  The toner supply pipe 25 is long in the vertical direction, and has an upper end inclined toward the front side of the apparatus and a lower end inclined toward the back side of the apparatus. The tip of the toner supply pipe 25 has a tapered shape, and when the toner supply pipe 25 moves downward, the tip can enter the inside through a slit formed in the toner supply portion of the developing device 16. In addition, a spiral member for conveying toner is rotatably provided in the toner supply pipe 25.

[Intermediate transfer belt]
The intermediate transfer belt 7 is one to which the toner images of the respective colors formed on the photosensitive drum 2 are sequentially transferred, and is disposed below the photosensitive drum 2 and the toner storage portion 5. The intermediate transfer belt 7 is stretched between a driving roller 35 and a driven roller 36 that are disposed to face each other. Here, it is preferable that the radius of the driving roller 35 is 20 mm or less, and the winding angle of the intermediate transfer belt 7 around the driving roller 35 is set to 90 ° or more. In this embodiment, the radius of the driving roller 35 is 15 mm, and the winding angle of the intermediate transfer belt 7 around the driving roller 35 is set to 120 °. Further, the portion of the intermediate transfer belt 7 facing the photosensitive drum 2 is configured to abut against the photosensitive drum 2 by a pair of primary transfer rollers 37a and 37b.

  The arrangement of these constituent members will be described in more detail. The driving roller 35 is located almost directly below the contact portion between the photosensitive drum 2 and the rotary developing device 3, and the center thereof is located further below the lowermost end of the rotary developing device 3. And it drives by the drive part containing the motor and gear which are not shown in figure. The driven roller 36 is disposed in the vicinity of the bottom of the toner container 5 on the front side of the apparatus, and the height position thereof is substantially the same as that of the photosensitive drum 2. The driven roller 36 is urged away from the driving roller 35 by a spring 38, whereby a predetermined tension is applied to the intermediate belt 7. The primary transfer rollers 37 a and 37 b are provided close to each other and below the photosensitive drum 2, so that a predetermined range of the intermediate transfer belt 7 is in contact with the photosensitive drum 2.

  The secondary transfer roller 8 is for transferring the image transferred to the intermediate transfer belt 7 onto the conveyed paper, and is disposed below the drive roller 35 so as to face the drive roller 35. . A bias voltage for image transfer is applied to the secondary transfer roller 8 with respect to the paper by a voltage application unit (not shown). Further, a neutralizing brush (not shown) is provided in the paper conveyance path downstream from the secondary transfer roller 8.

[Intermediate transfer belt cleaning device]
A belt cleaning device 40 for cleaning the intermediate transfer belt 7 is provided on the back side of the driving roller 35 and below the rotary developing device 3. As shown in FIGS. 1 and 2, the belt cleaning device 40 includes a brush member 41, a cleaning roller 42, a blade 43, and a collection spiral 44. The brush member 41 is provided at a position facing the drive roller 35 and is disposed so as to be in sliding contact with the surface of the intermediate transfer belt 7. The cleaning roller 42 is disposed above the brush member 41 and is in contact with the brush member 41. Here, a high voltage power source 46 for applying a high voltage to the cleaning roller 42 is provided. In this embodiment, since positively charged toner is used, the voltage applied from the high voltage power supply 46 is −500 V to −2 Kv. The blade 43 is disposed such that the tip thereof is in contact with the surface of the cleaning roller 42, and the other end is supported by a support member 43 a, and is disposed such that the angle θ formed with the horizontal line is equal to or greater than the repose angle of the toner. . The collection spiral 44 is arranged below the blade 43, and a line connecting the center of the brush member 41, the center of the cleaning roller 42, and the center of the collection spiral 44 forms a triangle. The frame 40a of the cleaning device 40 also has a triangular cross section.

  Further, as shown in FIG. 3, swing plates 45 are swingably supported at both ends of the shaft 142 of the cleaning roller 42 rotatably supported by the frame body 40a, and the shaft 141 of the brush member 41 is swung. The moving plate 45 is rotatably supported. Further, a torsion spring 144 is provided on the shaft 142 of the cleaning roller 42, one end is fixed to the frame body 40 a, and the other end is in contact with the opposite side of the intermediate transfer belt 7 of the shaft 141 of the brush member 41. An eccentric cam 136 having a large diameter portion and a small diameter portion is provided at the end of the shaft 135 of the drive roller 35 so as to be rotatable relative to the shaft 135. On the other hand, a cam receiving portion 141 a is fixed to the end portion of the shaft 141 of the brush member 41 at a position facing the eccentric cam 136. A cam gear 136a is coaxially fixed to the eccentric cam 136, and this cam gear 136a meshes with a drive gear 150 driven by a drive means (not shown).

[Fixing device]
The fixing device 9 is for fusing and fixing the toner transferred onto the paper, and is disposed below the rotary developing device 3 and on the back side of the device. The fixing device 9 includes a heating roller 9a having a built-in heater and a pressure roller 9b that is in pressure contact with the heating roller 9a.

[Discharge part]
In the printer 1, a discharge unit 50 is formed on the upper surface of the apparatus, that is, above the laser unit 4, the toner supply device 6, and the toner storage unit 5. The discharge unit 50 is the lowest on the laser unit 4 side (apparatus back side) and gradually increases as it goes to the toner storage unit 5 side (on the front side of the apparatus), and the toner storage unit connected to the curved surface part. 5 and a flat portion located above 5.

[Paper Feeder]
At the bottom of the apparatus, there is provided a paper feeding unit 51 for storing paper and sending out the stored paper. The paper feed unit 51 has a paper feed cassette 52 having a placement plate on which paper is placed, a forward feed roller 53 for taking out the paper on the placement plate, and for feeding the paper one by one to the transport path. And a double feed prevention mechanism 54 composed of a pair of rollers. The paper feed cassette 52 can be pulled out to the front side of the apparatus.

[Transport section]
Between the paper feed unit 51 and the discharge unit 50, a transport unit that transports paper is provided. The conveyance unit reaches the first conveyance path 55 from the paper supply unit 51 to the secondary transfer roller 8, the second conveyance path 56 from the secondary transfer roller 8 to the fixing device 9, and the fixing device 9 to the discharge unit 50. And a third conveyance path 57. Further, a branch claw 58 is provided at the outlet of the fixing device 9, and a return conveyance path for returning the sheet to the first conveyance path 55 between the branch claw 58 and the first conveyance path 55. 59 is provided.

  The first conveyance path 55 includes a curved path 55a for reversing the conveyance direction while conveying the sheet fed from the paper feed cassette 52 upward, and a straight path 55b extending from the curved path 55a to the secondary transfer roller 8. And have. These conveyance paths are formed by a pair of guide plates and rollers that convey the sheet while guiding the sheet, and a sensor for detecting the sheet is provided at a predetermined position. In addition, a registration roller pair 60 for controlling the sheet conveyance timing is disposed on the straight path 55b.

  The second conveyance path 56 is formed substantially linearly, and includes a guide plate and a pair of rollers that convey the sheet while guiding the sheet. In addition, a sensor for detecting a sheet is provided at a predetermined position on the conveyance path.

  The third conveyance path 57 has a vertical conveyance path formed on the downstream side of the branch claw 58 in the conveyance direction. That is, after passing through the branching claw 58, the sheet is conveyed substantially vertically upward and discharged to the discharge unit 50. The third transport path 57 is also composed of a guide plate and a pair of rollers that transport the paper while guiding it, as described above.

  The return conveyance path 59 branches downward from the third conveyance path 57 at the portion where the branch claw 58 is provided, and passes below the fixing device 9, the second conveyance path 56, the secondary transfer roller 8, and the registration roller pair 60. Further, this is a further upward conveying path, and joins the upstream side of the first conveying path 55 in the conveying direction of the registration roller pair 60. That is, the return conveyance path 59 is provided between the straight path 55b of the first conveyance path 55 and the second conveyance path 56 and the sheet feeding cassette 52 in the up-down direction, and allows the sheet that has passed through the fixing device 9 to be secondary This is a conveyance path for returning the registration roller pair 60 disposed on the upstream side of the transfer roller 8 to the further upstream side. Similarly to the above, the return conveyance path 59 is also composed of a guide plate and a roller pair for conveying the sheet while guiding the sheet, and a sheet detection sensor is provided at a predetermined position.

[Paper Tray]
A paper feed tray 65 is disposed below the toner container 5 and above the paper feed cassette 52 so as to form a side wall on the front side of the apparatus. The lower end of the sheet feeding tray 65 is supported so as to be freely rotatable (openable and closable) in the vicinity of the curved path 55a of the first conveying path 55, and the upper end of the sheet feeding tray 65 is tilted toward the front of the apparatus with the pivot fulcrum 65a as a center. It is possible. When the paper feed tray 65 is opened in this way, paper can be placed on the paper feed tray 65 and fed to the curved path 55 a of the first transport path 55.

[Image forming operation]
Next, the image forming operation will be briefly described. First, when the color printer is turned on, various parameters are initialized, and initial settings such as setting the temperature of the fixing unit are executed. When image data is input from a computer or the like connected to the printer and an instruction to start printing is given, an image forming operation is executed as follows. During the image forming operation, the toner supply pipe 25 is moved to the upper retracted position. Therefore, the laser beam path is not blocked by the toner supply pipe 25.

  First, the photosensitive drum 2 is charged by the charging roller 10. Thereafter, scanning exposure corresponding to the image data is performed on the photosensitive drum 2 by the laser unit 4, and an electrostatic latent image is formed on the photosensitive drum 2. Next, the rotary developing device 3 is rotated so that the corresponding color developing device 16 is opposed to the photosensitive drum 2. In this state, the electrostatic latent image on the photosensitive drum 2 is developed with the corresponding color toner. The developed image is transferred to the intermediate transfer belt 7. A full color image is formed on the intermediate transfer belt 7 by sequentially repeating the above operation for each color. The residual toner remaining on the photosensitive drum 2 is cleaned by the drum cleaning device 11 and discarded in a waste toner container (not shown).

  As described above, in the process of primary transfer of the toner image to the intermediate transfer belt 7, the secondary transfer roller 8 is separated from the intermediate transfer belt 7. On the other hand, when the full-color toner image is formed on the intermediate transfer belt 7, the secondary transfer roller 8 is brought into contact with the transfer belt 51. On the other hand, in the paper supply unit 51, one sheet of paper is taken out from the paper supply cassette 52 by the forward feed roller 54 and the double feed prevention mechanism 55 and is transported to the registration roller pair 60 through the first transport path 55. Thereafter, the sheet is conveyed from the registration roller pair 60 in time with image formation on the intermediate transfer belt 7 and guided to the secondary transfer roller 8. The secondary transfer roller 8 is in contact with the intermediate transfer belt 7, and the full color image formed on the intermediate transfer belt 7 is transferred onto the sheet by the transfer bias applied to the secondary transfer roller 8. The sheet is guided to the fixing device 9 through the second conveyance path 56, and the image is fixed on the sheet by heating and pressing by the fixing device 9. In the case of single-sided printing, the paper is guided to the third conveyance path 57 via the branching claw 58 and discharged to the discharge unit 50.

  In the case of duplex printing, the sheet that has passed through the fixing device 9 is guided to the return conveyance path 59 side by the branching claw 58 and returned to the first conveyance path 55 again. The sheet returned to the first conveyance path 55 is temporarily stopped by the registration roller pair 60. Then, after the image on the back side is formed on the intermediate transfer belt 7 by the same operation as described above, the sheet waiting on the registration roller pair 60 is sent to the secondary transfer roller 8 side in time. Thereafter, the same operation as described above is executed, guided to the third conveyance path 57 side through the branching claw 58, and discharged to the discharge unit 50.

[Cleaning operation of intermediate transfer belt]
In the process in which the toner image is primarily transferred to the intermediate transfer belt 7 in the image forming apparatus and in the process in which the full color image formed on the intermediate transfer belt 7 is transferred to the sheet, the brush member 41 of the intermediate transfer body cleaning device 40 is intermediate. It is separated from the transfer belt 7. On the other hand, after the full-color toner image is transferred onto the sheet, that is, after the secondary transfer, the brush member 41 of the intermediate transfer body cleaning device 40 is pressed against the intermediate transfer belt 7 to clean the toner remaining on the intermediate transfer belt 7. .

  In the cleaning device 40, the deposit on the intermediate transfer belt 7 is scraped off by the brush member 41. Here, when a high voltage is applied from the high voltage power supply 46 to the cleaning roller 42, a voltage is also applied to the brush member 41 in contact with the cleaning roller 42, and the residual toner on the intermediate transfer belt 7 is scraped off by the brush member 41. It is done. Thereafter, the deposit on the brush member 41 is collected by the cleaning roller 42. Then, the deposit collected on the cleaning roller 42 side is scraped off from the surface of the cleaning roller 42 by the blade 43 and is collected by a collecting spiral 44 to a collecting unit (not shown).

  Specifically, at the time of image formation, the cam gear 136 a is driven by the drive gear 150, but the large-diameter portion of the eccentric cam 136 contacts the cam receiving portion 141 a provided on the shaft 141 of the brush member 41. As a result, the shaft 141 of the brush member 41 swings to the left (the back side of the apparatus) in each drawing around the shaft 142 of the cleaning roller 42 together with the swing plate 45. Therefore, the distance between the shaft 135 of the driving roller 35 and the shaft 141 of the brush member 41 is increased, and the intermediate transfer belt 7 and the brush member 41 are separated from each other. On the other hand, when cleaning the intermediate transfer belt 7, the cam gear 136 a is rotated so that the small-diameter portion of the eccentric cam 136 contacts the cam receiving portion 141 a provided on the shaft 141 of the brush member 41. Then, the shaft 141 of the brush member 41 is swung to the right about the shaft 142 of the cleaning roller 42 together with the rocking plate 45 by the torsion spring 144, and the shaft 135 of the driving roller 35 and the shaft 141 of the brush member 41 are The distance becomes smaller. Accordingly, the brush member 41 is pressed against the intermediate transfer belt 7, and the intermediate transfer belt 7 is cleaned by the brush member 41. After cleaning the entire circumference of the intermediate transfer belt 7, the brush member 41 is separated from the intermediate transfer belt 7. The operation at that time is the same as that at the time of image formation.

  On the other hand, in the paper supply unit 51, one sheet of paper is taken out from the paper supply cassette 52 by the forward feed roller 54 and the double feed prevention mechanism 55 and is transported to the registration roller pair 60 through the first transport path 55. Thereafter, the sheet is conveyed from the registration roller pair 60 in time with image formation on the intermediate transfer belt 7 and guided to the secondary transfer roller 8. The secondary transfer roller 8 is in contact with the intermediate transfer belt 7, and the full color image formed on the intermediate transfer belt 7 is transferred onto the sheet by the transfer bias applied to the secondary transfer roller 8. The sheet is guided to the fixing device 9 through the second conveyance path 56, and the image is fixed on the sheet by heating and pressing by the fixing device 9. In the case of single-sided printing, the paper is guided to the third conveyance path 57 via the branching claw 58 and discharged to the discharge unit 50.

  In the case of duplex printing, the sheet that has passed through the fixing device 9 is guided to the return conveyance path 59 side by the branching claw 58 and returned to the first conveyance path 55 again. The sheet returned to the first conveyance path 55 is temporarily stopped by the registration roller pair 60. Then, after the image on the back side is formed on the intermediate transfer belt 7 by the same operation as described above, the sheet waiting on the registration roller pair 60 is sent to the secondary transfer roller 8 side in time. Thereafter, the same operation as described above is executed, guided to the third conveyance path 57 side through the branching claw 58, and discharged to the discharge unit 50.

[Toner supply operation]
When supplying toner to the developing device 16, the rotary developing device 3 is rotated so that the developing device 16 to which the toner is to be supplied is positioned at a supply position as shown in FIG. The rotation of the rotary developing device 3 is locked in this state. Next, the toner supply pipe 25 is moved downward to be positioned at the supply position. That is, when a motor (not shown) is driven, the toner supply pipe 25 moves downward. On the other hand, toner is supplied from the toner storage unit 5 to the toner supply pipe 25 side via the transport pipe 26. Then, the tip of the toner supply pipe 25 enters the inside of the developing device 16 through a slit as a toner supply port. At the time of the downward movement of the toner supply pipe 25, the outer cylinder portion constituting the toner supply pipe 25 rotates with respect to the inner cylinder portion, and when the tip of the toner supply pipe 25 enters the inside of the developing device 16, The opening of the outer cylinder part coincides with the opening of the inner cylinder part. That is, the shutter mechanism is opened, and the toner inside the toner supply pipe 25 is supplied into the developing device 16.

  When the toner supply pipe 25 is located at the supply position, the toner supply pipe 25 blocks the laser light path from the laser unit 4 to the photosensitive drum 2. However, since the toner supply operation by the toner supply pipe 25 and the image forming operation are not executed simultaneously, there is no problem.

[Effect of this embodiment]
In the present embodiment, the brush member 41 of the intermediate transfer member cleaning device 40 is separated from the intermediate transfer belt 7 during image formation. On the other hand, when cleaning the intermediate transfer belt 7, the brush member 41 of the intermediate transfer body cleaning device 40 is pressed against the intermediate transfer belt 7 to clean the toner remaining on the intermediate transfer belt 7. That is, when cleaning the intermediate transfer belt 7, it is not necessary to swing only the brush member 41 and press or separate the entire cleaning device 40 from the intermediate transfer belt 7. Therefore, a complicated and large mechanism for moving the cleaning device 40 is not required, and the cleaning device 40 can be made compact. Therefore, compared with the case where the entire cleaning device 40 is separated from or pressed against the intermediate transfer belt 7, the intermediate transfer member cleaning device 40 can be reduced in size, and the degree of freedom in layout of the cleaning device 40 is improved and image formation is performed. The apparatus 1 can be reduced in size and cost. Further, since it is the brush member 41 with a small load fluctuation that directly presses and separates from the intermediate transfer belt 7, the image quality of the formed image can be improved. Further, when a high voltage is applied from the high voltage power supply 46 to the cleaning roller 42, a voltage is also applied to the brush member 41 in contact with the cleaning roller 42, and the residual toner on the intermediate transfer belt 7 is scraped off by the brush member 41. . Thereafter, the deposit on the brush member 41 is collected by the cleaning roller 42. Therefore, the cleaning effect can be enhanced.

1 is a schematic configuration diagram of a color printer according to an embodiment of the present invention. The enlarged view of a cleaning apparatus. The block diagram of a cleaning apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color printer 2 Photosensitive drum 3 Rotating developing device 4 Laser unit 5 Toner accommodating part 6 Toner supply device 7 Intermediate transfer belt 8 Secondary transfer roller 9 Fixing device 15 Rotating frame 16 Developer 25 Toner supply pipe 35 Driving roller 40 Intermediate transfer Body cleaning device 41 Brush member 42 Cleaning roller 43 Blade 44 Recovery spiral 45 Swing plate 46 High-voltage power supply 135 Drive roller shaft 136 Eccentric cam 141 Brush member shaft 141a Cam receiving portion 142 Cleaning roller shaft 144 Torsion spring

Claims (8)

An image carrier on which an electrostatic latent image is formed on the surface;
A developing device for developing an electrostatic latent image on the surface of the image carrier;
An intermediate transfer member to which a toner image formed on the image carrier, which is arranged facing the image carrier, is transferred;
A transport path for transporting the paper on which the toner image is formed;
An intermediate transfer body cleaning device for cleaning the intermediate transfer body,
The intermediate transfer member cleaning device includes:
A brush member that is disposed so as to be press-contacted and separated from the intermediate transfer member and is rotatable, and for cleaning the surface of the intermediate transfer member;
A cleaning roller that frictionally contacts the brush member and electrically adsorbs toner adhering to the brush member;
An image forming apparatus. The cleaning roller is disposed above the brush member;
A swing mechanism that swings the brush member about the shaft of the cleaning roller;
A blade that is disposed on a side of the cleaning roller and that has a tip pressed against the surface of the cleaning roller to remove deposits on the surface of the cleaning roller;
The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the blade is disposed such that an angle formed with a horizontal line is equal to or greater than a repose angle of the toner. A recovery spiral disposed below the blade for recovering deposits removed by the blade;
A line connecting the center of the brush member, the center of the cleaning roller, and the center of the recovery spiral forms a triangle,
The image forming apparatus according to claim 3. The intermediate transfer body is an intermediate transfer belt supported by a plurality of support rollers,
The swing mechanism is provided at an end portion of the shaft of the brush member, and is provided at an end portion of the shaft of the brush member. A cam receiver that contacts the eccentric cam; and a biasing member that biases the shaft of the brush member toward the intermediate transfer belt.
The brush member is swung by contact between the eccentric cam and the cam receiving portion, and the brush member is pressed against and separated from the intermediate transfer belt.
The image forming apparatus according to claim 2. The image carrier is a rotatable photosensitive drum,
The developing device is disposed adjacent to the photosensitive drum, and is provided corresponding to a rotating frame that rotates about an axis parallel to the rotating shaft of the photosensitive drum, and corresponding to a plurality of colors of toner. A plurality of developing devices held in a frame;
The intermediate transfer body cleaning device is disposed in a substantially triangular space formed between the rotary frame body, the intermediate transfer body, and the paper transport path.
The image forming apparatus according to claim 1. A cleaning device for cleaning an intermediate transfer member of an image forming apparatus,
A brush member that is rotatable with respect to the intermediate transfer member, and for cleaning the surface of the intermediate transfer member;
A cleaning roller that is disposed above the brush member and that adsorbs toner adhering to the brush member by frictional contact with the brush member;
A blade that is disposed on the side of the cleaning roller and whose tip is pressed against the surface of the cleaning roller to remove deposits on the surface of the cleaning roller;
A recovery spiral disposed below the blade and for recovering deposits removed by the blade;
Intermediate transfer body cleaning device.   The intermediate transfer member cleaning according to claim 7, further comprising a voltage applying device that applies a high voltage to the cleaning roller in order to electrically adsorb the toner adhering to the brush member.

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