JP2009211096A - Image forming apparatus and image forming unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact image forming apparatus. <P>SOLUTION: An intermediate transfer body 64 is provided to be inclined such that a secondary transfer position on the intermediate transfer body 64 is made lower than the heating roll 92 of a fixing device 90 and an anti-secondary transfer position is made higher than the heating roll 92 of the fixing device 90, and an intermediate transfer cleaner 82 is provided to the anti-secondary transfer position. The image forming unit 96 is constituted to be curved along the curved surface of a rotary developing device 38, and is arranged between the rotary developing device 38 and the fixing device 90. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus of a type in which toner is carried on a belt-shaped member.

  For example, Patent Document 1 discloses a cleaning device that has a plurality of cleaning rolls and that operates a cleaning electric field capable of adsorbing residual toners having different polarities on these cleaning rolls. Patent Document 2 and Patent Document 3 disclose an intermediate transfer unit formed in a substantially square shape, and Patent Document 4 discloses a transfer belt formed in a substantially triangular shape. Patent Document 5 discloses a color image forming apparatus in which a cleaning device is disposed at an end portion of a photoreceptor belt formed in a substantially flat shape.

JP 2003-098839 A JP 2001-175077 A JP 2002-341706 A JP-A-8-328348 JP-A-3-220571

  The present invention has been made from the above-described background, and an object thereof is to provide a downsized image forming apparatus.

  In order to achieve the above object, an image forming apparatus according to the present invention includes an image forming apparatus main body, an opening / closing cover rotatably provided on the upper part of the image forming apparatus main body, and a toner image provided on the opening / closing cover. An image forming unit that is disposed below the discharge unit and is attached / detached by opening the opening / closing cover, and charges the photoconductor A charging device; an intermediate transfer device including an intermediate transfer body to which a toner image on the photoconductor is primarily transferred; a photoconductor cleaner for cleaning toner remaining on the photoconductor after the primary transfer; and the intermediate transfer device. The image forming unit integrated with an intermediate transfer cleaner for cleaning the toner remaining on the intermediate transfer body after the secondary transfer from the toner to the paper, and the primary transfer to the intermediate transfer body A fixing device that includes a secondary transfer position where the toner image is secondarily transferred to the paper, and a heating roll, and is provided above the secondary transfer position and fixes the toner image secondarily transferred onto the paper to the paper. And a rotary developing device that is provided in the image forming apparatus main body and rotates with a plurality of developing devices that respectively form a plurality of color toner images on the photoreceptor, and the image forming unit includes the image forming unit, The intermediate transfer member is inclined and provided such that the secondary transfer position in the intermediate transfer member is lower than the heating roll of the fixing device and the anti-secondary transfer position is higher than the heating roll of the fixing device, The intermediate transfer cleaner is provided at an anti-secondary transfer position, and the image forming unit is configured to bend along the curved surface of the rotary developer, and is disposed between the rotary developer and the fixing device. It is.

  In addition, an image forming unit according to the present invention includes a photosensitive member, a charging device that charges the photosensitive member, an intermediate transfer device that includes an intermediate transfer member to which a toner image on the photosensitive member is primarily transferred, and the primary transfer device. A photoreceptor cleaner that cleans toner remaining on the photoreceptor after transfer and an intermediate transfer cleaner that cleans toner remaining on the intermediate transfer body after secondary transfer from the intermediate transfer device to a sheet are integrated, The intermediate transfer member is inclined and provided so that the secondary transfer position on the intermediate transfer member is lower than the heating roll of the fixing device and the anti-secondary transfer position is higher than the heating roll of the fixing device. The intermediate transfer cleaner is provided at a next transfer position, and is configured to bend along the curved surface of a rotary developer provided in the image forming apparatus main body. It is arranged between the wearing device.

  According to the image forming apparatus of the present invention, the image forming apparatus can be downsized.

1 is a diagram showing an outline of an image forming apparatus 10 according to an embodiment of the present invention. 3 is a diagram schematically showing an intermediate transfer member cleaner 82. FIG. FIG. 6 is a diagram illustrating the position of the intermediate transfer body cleaner 82 when the second short surface 64b is formed and the position of the intermediate transfer body cleaner 82 when the second short surface 64b is not formed. It is a figure which shows typically the intermediate transfer body 64 formed in the substantially triangular shape.

Hereinafter, a first embodiment of the present invention will be described.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 of the present embodiment has an image forming apparatus main body 12, and an open / close cover 16 that is rotatable about a rotation fulcrum 14 is provided on the upper portion of the image forming apparatus main body 12. For example, a one-stage sheet feeding unit 18 is disposed below the image forming apparatus main body 12.

  The paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 in which paper is stored. A feed roll 24 that feeds paper from the paper feed cassette 22 and a retard roll 26 that sprinkles the fed paper one by one are arranged in the upper vicinity of the rear end of the paper feed cassette 22.

  The conveyance path 28 is a sheet path from the feed roll 24 to the discharge port 30, and this conveyance path 28 is in the vicinity of the back side (right side surface in FIG. 1) of the image forming apparatus main body 12 and is described later from the sheet feeding unit 18. The fixing device 90 is formed substantially vertically. A secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later, are arranged on the upstream side of the fixing device 90 in the conveyance path 28, and the registration roll 32 is located upstream of the secondary transfer roll 80 and the secondary transfer backup roll 72. Is arranged. In addition, a discharge roll 34 is disposed in the vicinity of the discharge port 30 of the conveyance path 28.

  Therefore, the sheet fed from the sheet feeding cassette 22 of the sheet feeding unit 18 by the feed roll 24 is turned by the retard roll 26 and only the uppermost sheet is guided to the conveyance path 28 and temporarily stopped by the registration roll 32. Then, a toner image is transferred between a secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later. The transferred toner image is fixed by the fixing device 90, and the discharge port 34 discharges the discharge port 30. Are discharged to a discharge portion 36 provided on the upper portion of the opening / closing cover 16. The discharge portion 36 has a low discharge port portion and is inclined so as to gradually increase toward the front direction (left direction in FIG. 1).

  In the image forming apparatus main body 12, for example, a rotary developing unit 38 is disposed at a substantially central portion. The rotary developing unit 38 includes developing units 42a to 42d that form toner images of four colors of yellow, yellow, magenta, cyan, and black in the developing unit main body 40, respectively. Rotates counterclockwise (counterclockwise in FIG. 1) about the rotary developer center 44. Each of the developing units 42a to 42d has developing rolls 46a to 46d and is pressed in the normal direction of the developing unit main body 40 by elastic bodies 48a to 48d such as coil springs.

  The rotary developing unit 38 is arranged so that the photosensitive member 50 comes into contact therewith, and the developing rolls 46 a to 46 d are not in contact with the photosensitive member 50, and a part of the outer periphery of each of the developing rollers 46 a to 46 d. For example, 2 mm protrudes from the outer periphery in the radial direction. Further, a tracking roll (not shown) having a diameter slightly larger than the diameter of the developing rolls 46a to 46d is provided at both ends of each of the developing rolls 46a to 46d so as to rotate coaxially with the developing rolls 46a to 46d. Yes. In other words, the developing rolls 46a to 46d of the developing units 42a to 42d are arranged on the outer periphery of the developing unit main body 40 at intervals of 90 ° around the rotary developing unit center 44, and the tracking rolls of the developing rolls 46a to 46d are photosensitive. The latent images on the photoconductor 50 are in contact with flanges (not shown) provided at both ends of the photoconductor 50, and a predetermined gap is formed between the developing rolls 46a to 46d and the photoconductor 50. Develop with toner.

Below the photoconductor 50, a charging device 52 comprising a charging roll for uniformly charging the photoconductor 50 is provided. Further, an image carrier cleaner 54 is in contact with the photoconductor 50 on the upstream side of the charging device 52 in the rotation direction of the photoconductor 50. The image carrier cleaner 54 includes, for example, a cleaning blade 56 that scrapes off toner remaining on the photoconductor 50 after primary transfer, and a toner recovery bottle 58 that collects toner scraped off by the cleaning blade 56.
The back side (right side in FIG. 1) of the toner collection bottle 58 is formed with a rib or the like, and is curved so as to convey the paper smoothly, thereby constituting the conveyance path 28.

  Below the rotary developing unit 38, an exposure device 60 for writing a latent image on the photosensitive member 50 charged by the charging device 52 with a light beam such as a laser beam is disposed. Further, an intermediate transfer device 62 is provided above the rotary developing unit 38 to primarily transfer the toner image visualized by the rotary developing unit 38 at the primary transfer position and transport the toner image to a secondary transfer position described later.

The intermediate transfer device 62 includes, for example, an intermediate transfer body 64 (image carrier) such as an intermediate transfer belt, a primary transfer roll 66, a wrap-in roll 68, a wrap-out roll 70, a secondary transfer backup roll 72, a scraper backup roll 74, and a brush. It consists of a backup roll 76. In the present embodiment, the intermediate transfer member 64 will be described as an example of an image carrier. However, the present invention is not limited to this, and the image carrier according to the present invention includes the photoreceptor 50 and the like.
The intermediate transfer member 64 has elasticity, for example, and has a first long surface 64a, a second long surface 64c, a first short surface 64b, and a second short surface 64d above the rotary developing unit 38. It is stretched almost flat. In addition, the intermediate transfer member 64 includes a wrap-in roll 68 disposed upstream of the primary transfer roll 66 below the long surface (second long surface 64c) of the intermediate transfer member 64, and downstream of the primary transfer roll 66. An image carrier wrap region that abuts the photoreceptor 50 in a wrap shape with the wrap-out roll 70 disposed is wound around the photoreceptor 50 by a predetermined range and is driven by the rotation of the photoreceptor 50. In this way, the intermediate transfer member 64 is primarily transferred by the primary transfer roll 66 so that the toner images on the photosensitive member 50 are superposed in the order of, for example, yellow, magenta, cyan, and black. It is conveyed toward the next transfer roll 80.
Note that the wrap-in roll 68 and the wrap-out roll 70 are separated from the photoconductor 50.

Further, on the back side of the intermediate transfer body 64 (the right side surface in FIG. 1), a flat portion (that is, the first short surface 64d) is formed by the wrap-out roll 70 and the secondary transfer backup roll 72. The first short surface 64d becomes a secondary transfer portion and faces the conveyance path 28.
In the secondary transfer portion, the wrap-out roll 70 is arranged so that the intermediate transfer body 64 and the conveyance path 28 are at an angle of 12 °, for example.

On the front side of the intermediate transfer body 64 (left side surface in FIG. 1), a scraper backup roll 74 (a support roll disposed upstream in the rotation direction of the intermediate transfer body 64) and a brush backup roll 76 (the rotation of the intermediate transfer body 64). A substantially vertical flat surface portion (that is, the second short surface 64b) is formed by the support roll disposed on the downstream side in the moving direction. More specifically, the scraper backup roll 74 is located in the front direction (left direction in FIG. 1) than the brush backup roll 76. Therefore, the second short surface 64b slightly overhangs from the vertical state, and the outer peripheral surface faces downward. Further, the scraper backup roll 74 is higher than a heating roll 92 and a pressure roll 94 described later, and is lower than the discharge roll 34. Therefore, the intermediate transfer device 62 is inclined, and the second short surface 64b is at a higher position than the first short surface 64d.
The scraper backup roll 74 assists the scraper 84 described later to scrape off toner remaining on the intermediate transfer body 64 after the secondary transfer, and the brush backup roll 76 removes toner remaining on the intermediate transfer body 64 after the secondary transfer. A brush roll 86 to be described later assists in scraping.

  Above the long side (first long surface 64 a) of the intermediate transfer body 64, a sensor 78 such as a reflective photosensor is provided by being fixed to the back surface (inside) of the opening / closing cover 16. The sensor 78 reads a toner patch formed on the intermediate transfer body 64, detects the position of the intermediate transfer body 64 in the rotation direction, and detects the toner density.

  A secondary transfer roll 80 is opposed to the secondary transfer backup roll 72 of the intermediate transfer device 62 with the conveyance path 28 interposed therebetween. That is, the secondary transfer position in the secondary transfer portion is between the secondary transfer roll 80 and the secondary transfer backup roll 72, and the secondary transfer roll 80 is intermediate with the assistance of the secondary transfer backup roll 72. The toner image primarily transferred to the transfer body 64 is secondarily transferred onto the paper at the secondary transfer position. Here, the secondary transfer roll 80 is separated from the intermediate transfer member 64 while the intermediate transfer member 64 rotates three times, that is, while the toner images of three colors of yellow, magenta, and cyan are conveyed. When the image is transferred, it contacts the intermediate transfer member 64. In addition, a predetermined potential difference is generated between the secondary transfer roll 80 and the secondary transfer backup roll 72. For example, when the secondary transfer roll 80 is set to a high voltage, the secondary transfer backup 80 The roll 72 is connected to a ground (GND) or the like.

On the side opposite to the secondary transfer position of the intermediate transfer device 62, an intermediate transfer member cleaner 82 (cleaner) is in contact with the second short surface 64b. The intermediate transfer body cleaner 82 is, for example, a scraper 84 (first cleaning means) that scrapes and cleans toner remaining on the intermediate transfer body 64 after secondary transfer, and a brush roll that further scrapes off toner remaining after cleaning by the scraper 84. 86 (second cleaning means), a scraper 84, and a toner collection bottle 88 that collects toner scraped off by the brush roll 86. The scraper 84 is made of, for example, a thin plate made of stainless steel and is applied with a predetermined voltage. The brush roll 86 is made of, for example, an acrylic brush that has been subjected to a conductive treatment. In this way, by disposing the intermediate transfer body cleaner 82 so as to contact the substantially vertical second short surface 64b, the toner scraped off by the scraper 84 and the brush roll 86 is transferred to the toner recovery bottle 88 by its own weight. Collected. That is, by disposing the intermediate transfer body cleaner 82 at a position opposite to the second short surface 64b formed substantially vertically, a transport mechanism for transporting the scraped toner becomes unnecessary, and the apparatus has the following structure. Miniaturization is possible.
Further, while the intermediate transfer member 64 conveys the toner image, the scraper 84 and the brush roll 86 are separated from the intermediate transfer member 64 and come into contact with the intermediate transfer member 64 at a predetermined timing. Has been.

  A fixing device 90 is disposed above the secondary transfer position. The fixing device 90 includes a heating roll 92 and a pressure roll 94, fixes the toner image secondarily transferred to the sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72, and fixes the toner image to the discharge roll 34. Transport toward.

  The image forming unit 96 is obtained by integrating the intermediate transfer device 62, the photosensitive member 50, the charging device 52, the image carrier cleaner 54, and the intermediate transfer member cleaner 82. The image forming unit 96 is disposed immediately below the discharge portion 36 of the opening / closing cover 16. For example, the intermediate transfer device 62 is disposed between the rotary developing device 38 and the fixing device 90 to open the opening / closing cover 16. It is attached and detached by. In this example, since the intermediate transfer body cleaner 82 is disposed at a position facing the second short surface 64 b of the intermediate transfer device 62, the image forming unit 96 is thin and curved along the curved surface of the rotary developing device 64. Formed as a replacement unit.

Next, the operation of the above embodiment will be described.
When the image forming signal is sent, the photosensitive member 50 is uniformly charged by the charging device 52, and light is emitted from the exposure device 60 to the charged photosensitive member 50 based on the image signal. The light beam from the exposure device 60 exposes the surface of the photoconductor 50 to form a latent image. The latent image of the photoreceptor 50 formed by the exposure device 60 is developed with yellow, magenta, cyan, and black toner by the rotary developing unit 38 and is primarily transferred onto the intermediate transfer member 64. In the primary transfer, waste toner remaining on the photoreceptor 50 is scraped off and collected by the image carrier cleaner 54.

  On the other hand, the paper stored in the paper feed cassette 22 by a paper feed signal or the like is sent out by the feed roll 24, is turned by the retard roll 26, is guided to the transport path 28, is temporarily stopped by the registration roll 32, and the timing is reached. As a result, it is guided between the secondary transfer roll 80 and the secondary transfer backup roll 72. When the sheet is guided between the secondary transfer roll 80 and the secondary transfer backup roll 72, the toner image primarily transferred to the intermediate transfer body 64 is transferred to the sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72. Secondary transfer. Waste toner remaining on the intermediate transfer member 64 after the secondary transfer is scraped off and collected by the intermediate transfer member cleaner 82.

  The sheet onto which the toner image has been transferred passes through the opening 962 and is guided to the fixing device 90, where the toner image is fixed by the thermal pressure generated by the heating roll 92 and the pressure roll 94. The sheet on which the toner image is fixed is discharged from the discharge port 30 to the discharge unit 36 by the discharge roll 34.

In FIG. 2, an intermediate transfer member cleaner 82 is schematically shown. The first long surface 64a and the second long surface 64c of the intermediate transfer body 64 are formed to face each other, and face the toner carrying surfaces above and below the image forming apparatus 10, respectively. The first short surface 64d (not shown) and the second short surface 64b are formed to face each other, and the first short surface 64d is used as a transfer position of the toner image, and the second short surface. 64b is used as a remaining toner removal position. Accordingly, the intermediate transfer member cleaner 82 is disposed at a position facing the second short surface 64b, and abuts on the short surface 64b of the intermediate transfer member 64 when the toner is removed.
The scraper 84 is composed of a thin plate-like member, and a bias voltage having a polarity opposite to that of the toner is applied. When the intermediate transfer body cleaner 82 contacts the intermediate transfer body 64, the scraper 84 contacts the intermediate transfer body 64 at a position facing the scraper backup roll 72, and the toner adhered to the surface of the intermediate transfer body 64 at the tip portion. Scrape off. Therefore, the scraper 84 can efficiently scrape the toner that is highly stacked on the intermediate transfer member 64.

  The brush roll 86 is rotatably provided and has a chargeable fur brush formed on the surface. When the intermediate transfer body cleaner 82 contacts the intermediate transfer body 64, the brush roll 86 contacts the intermediate transfer body 64 at a position facing the brush backup roll 76 and rotates in a direction against the rotation of the intermediate transfer body 64. The brush formed on the surface of the brush roll 89 scrapes off the toner adhering to the surface of the intermediate transfer member 64 as the brush roll 86 rotates. The brush roll 86 may be a conductive roll having no brush structure.

  The brush roll 86 is in contact with the second short surface 64 b of the intermediate transfer body 64 on the downstream side of the scraper 84. As a result, the toner adhering to the intermediate transfer body 64 is scraped off mainly by the scraper 84 to form a thin layer, and the brush roll 86 scrapes off the thin toner layer.

FIG. 3 shows the position of the intermediate transfer member cleaner 82 when the second short surface 64b is formed, and the position of the intermediate transfer member cleaner 82 when the second short surface 64b is not formed. When the image forming apparatus 10 is downsized, it is necessary to make the position of the fixing device 90 as low as possible. Therefore, as shown in FIGS. 3A and 3B, the first short surface 64d that is the secondary transfer position needs to be lowered. Accordingly, the substantially flat intermediate transfer body 64 is inclined so as to be higher on the front side (left side in FIG. 3).
As shown in FIG. 3A, when the second short surface 64b having a size necessary for toner cleaning is formed, the intermediate transfer body cleaner 82 is placed at a position facing the second short surface 64b. Can be arranged.
On the other hand, as shown in FIG. 3B, when the second short surface 64b is not formed, it is necessary to arrange the intermediate transfer member cleaner 82 on one of the long surfaces. In this case, it is necessary to make the image forming apparatus main body 12 higher than the case shown in FIG. That is, the image forming apparatus main body 12 can be miniaturized by providing a substantially flat intermediate transfer member 64 with a short surface and disposing the intermediate transfer member cleaner 82 at a position facing the short surface.

  As described above, the image forming apparatus 10 according to the present embodiment can improve the removal efficiency of the toner attached to the intermediate transfer body 64 and can suppress the height of the entire apparatus.

In the above-described embodiment, the intermediate transfer body 64 provided at a position where the two long surfaces and the two short surfaces face each other has been described as a specific example. However, the present invention is not limited to this. It may be a flat triangular intermediate transfer body 64.
In FIG. 4, an intermediate transfer member 64 formed in a substantially triangular shape is illustrated. The intermediate transfer member 64 is formed into a flat and substantially triangular shape by the secondary transfer backup roll 72, the scraper backup roll 74, and the brush backup roll 76. As described above, even when the first short surface 64 d is not formed, the height of the image forming apparatus main body 12 can be suppressed by making the intermediate transfer body cleaner 82 face the short surface of the intermediate transfer body 64. In this case, the secondary transfer backup roll 72 needs to be approximately the same size as the photoconductor 50 in order to form the secondary transfer portion. Further, since the sheet needs to enter at an angle of about 12 ° with respect to the secondary transfer portion formed by the secondary transfer backup roll 72 and the secondary transfer roll, the conveyance path 28 is curved.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 12 ... Image forming apparatus main body 18 ... Paper feed unit 28 ... Conveyance path 38 ... Rotary developing device 42a-42d ... Developing device 46a-46d ... Development Roll 50 ... Photoconductor 52 ... Charging device 54 ... Image carrier cleaner 60 ... Exposure device 62 ... Intermediate transfer device 64 ... Intermediate transfer member 80 ... Secondary transfer roll 82 ... Intermediate transfer member cleaner 90 ... Fixing device

Claims (2)

An image forming apparatus main body;
An opening / closing cover provided rotatably on the upper part of the image forming apparatus main body;
A discharge portion provided on the opening / closing cover and for discharging the paper on which the toner image is fixed;
An image forming unit that is disposed below the discharge unit and is attached and detached when the opening / closing cover is opened. The image forming unit includes a photoconductor, a charging device that charges the photoconductor, and a toner image on the photoconductor. An intermediate transfer device having an intermediate transfer member to be transferred; a photoconductor cleaner for cleaning toner remaining on the photoconductor after the primary transfer; and a secondary transfer from the intermediate transfer device to a sheet to the intermediate transfer member after the secondary transfer. The image forming unit integrated with an intermediate transfer cleaner for cleaning residual toner; and
A secondary transfer position where the toner image primarily transferred to the intermediate transfer member is secondarily transferred to a sheet;
A fixing device that includes a heating roll and is provided above the secondary transfer position and fixes the toner image secondarily transferred to the paper to the paper;
A rotary developing device provided in the image forming apparatus main body, and having a plurality of developing devices that respectively form a plurality of color toner images on the photoreceptor, and rotating.
The image forming unit is configured such that the intermediate transfer body has a secondary transfer position on the intermediate transfer body that is lower than the heating roll of the fixing device and an anti-secondary transfer position that is higher than the heating roll of the fixing device. The intermediate transfer cleaner is provided at an inclined position, the intermediate transfer cleaner is provided at the anti-secondary transfer position, and the image forming unit is configured to be curved along the curved surface of the rotary developer. The rotary developer and the fixing device Being placed between,
An image forming apparatus. A photoreceptor,
A charging device for charging the photoreceptor;
An intermediate transfer device including an intermediate transfer body on which a toner image on the photosensitive member is primarily transferred;
A photoreceptor cleaner for cleaning toner remaining on the photoreceptor after the primary transfer;
An intermediate transfer cleaner that cleans the toner remaining on the intermediate transfer body after the secondary transfer from the intermediate transfer device to the paper; and
The intermediate transfer member is inclined and provided such that the secondary transfer position in the intermediate transfer member is lower than the heating roll of the fixing device and the anti-secondary transfer position is higher than the heating roll of the fixing device;
The intermediate transfer cleaner is provided at the anti-secondary transfer position;
Being curved along the curved surface of a rotary developer provided in the image forming apparatus main body, and being disposed between the rotary developer and the fixing device;
An image forming unit characterized by.

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