JP5253076B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a recorded image display apparatus, and a facsimile machine that forms a visible image by electrophotography. Specifically, the present invention relates to an image forming apparatus that forms an image using a developing device having a transparent developing device and a colored developing device.

  At present, an electrophotographic image forming apparatus is widely used in a multifunction machine having a copy and printer function, a facsimile, and the like. In recent years, an electrophotographic full color image forming apparatus is particularly widespread.

  As color image reproduction by a full-color image forming apparatus becomes widespread, it is desired to improve the color reproduction range and to improve image quality by reducing the graininess of the image.

  Aside from this point of view, a new expression different from the color is given by giving glossiness to the entire image and finishing it to a photographic tone or by changing the glossiness (glossiness) in the image. Printed materials have begun to spread in recent years.

  In order to realize such an expression with an electrophotographic image forming apparatus, an image forming method using a transparent toner has been proposed.

For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-251717) describes a configuration including a developing unit capable of forming a transparent toner image in addition to four color developing units capable of forming four color toner images. In addition, a configuration (tandem configuration) is described in which a plurality of image forming units including a plurality of photoconductors and developing units corresponding thereto are arranged along the moving direction of the intermediate transfer member. Also described is a configuration (rotary configuration) having one photoconductor and rotating a plurality of developing units with respect to one development position. The rotary configuration is superior to the tandem configuration in that it is easy to achieve downsizing of the image forming apparatus.
JP 2006-251717 A

  As described above, the developing device using the transparent toner has a characteristic that it is weak against the mixing of other toners as compared with the developing device using the color toner. This is because even when a small amount of color toner is mixed with the transparent toner, the toner becomes noticeable immediately.

  Here, the problem that other color toners are mixed in the transparent developing device will be described as an example where the developing device has a rotary configuration.

  In the developing rotary, a plurality of developing devices are respectively held in close proximity, and the developing rotary is provided with a transport path for transporting each color toner to each of the developing devices arranged in proximity. Each transport path is provided with a replenishment port for receiving toner, and is configured to replenish different colors of replenishment toner from the toner replenishing device.

At this time, the toner replenishing device is provided so as to be separated from each conveyance path provided in the developing rotary for maintenance or the like. For this reason, when the toner replenishing device is separated from the replenishing port provided in each conveyance path, the toner is scattered from the toner discharge port (replenishing port) of the toner replenishing device. Usually, the transport paths provided in the developing rotary are provided close to each other in order to reduce the size of the apparatus. For this reason, there is a problem in that the replenishing port provided in the transport path for the transparent developing device is mixed with toner scattered from the transport path of the color developing device provided adjacently.
In particular, it was fatal for transparent toners that are vulnerable to color mixing.

  Therefore, the present invention provides an image forming apparatus capable of reducing the mixing of other toner into the transport path of the transparent developer when the toner replenishing device is separated from the toner transport path even if toner scattering occurs in the toner transfer section. It is intended to provide.

  In order to solve the above problems, an image forming apparatus according to the present invention includes the following.

An image carrier, a transparent developer for developing the electrostatic image formed on the image carrier with transparent toner, and a plurality of developers for developing the electrostatic image formed on the image carrier with colored toner, respectively. A plurality of transports for transporting toner to each of the transparent developer and the plurality of color developers by being connected to the color developer, the transparent developer, and the plurality of color developers, respectively. A plurality of replenishing ports that are provided in each of the plurality of transporting paths and that receive the corresponding toner, and that can be separated from each of the plurality of replenishing ports. A plurality of replenishing ports arranged adjacent to each other, and the plurality of replenishing ports, wherein the replenishing device replenishes the corresponding toner. Transport path to the developer for transparency The supplied port provided are arranged at the end of the array direction,
The replenishing device is connected to each of the plurality of replenished ports on the upper side in the direction of gravity, and has a plurality of replenishing ports for discharging the corresponding toner to each of the plurality of replenished ports, When a plurality of supply ports are separated from the plurality of supply ports, an area in which a movement trajectory of the supply port provided in the conveyance path to the color developer is projected downward in the gravitational direction. outside, the object supply port provided in the transport path of the the transparent developing unit is characterized that you have provided.

  According to the present invention, when the toner replenishing device is separated from the toner conveyance path, it is possible to reduce mixing of other toner into the conveyance path of the transparent developer even if toner scattering occurs in the toner delivery section. Can do.

[Embodiment 1]
Hereinafter, the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Example 1
FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus to which the present invention is applied. This image forming apparatus is an electrophotographic full-color image forming apparatus, and has a digital color image reading unit R in the upper part and a digital color image forming part P in the lower part.

  In the image reading unit R, reference numeral 31 denotes an original platen glass, and 32 denotes an original pressing plate that can be opened and closed with respect to the glass 31. A color original O is placed on the glass 31 with the image surface facing downward according to a predetermined placement standard, and the original pressure plate 32 is placed thereon to set the original O.

  A moving optical system 33 is driven to move along the lower surface of the glass 31. The moving optical system 33 optically scans the downward image surface of the document O on the glass 31. The original scanning light is imaged on a CCD 34, which is a photoelectric conversion element (solid-state imaging element), and is color-separated and read with three primary colors of RGB (red, green, and blue).

  The read RGB signals are input to an image processing unit (not shown).

  The image forming portion P is an electrophotographic image forming mechanism having one drum, a rotary developing configuration, and an intermediate transfer configuration.

  The outline of the operation of the image forming unit P is as follows.

  Based on an image signal, an electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum) 1 as an image carrier is exposed by a laser scanner 3 as an exposure device to form an electrostatic image.

  The electrostatic image formed on the photosensitive drum is sequentially formed for each color by a plurality of developing units arranged inside the developing rotary. Each developing device is replenished with toner in a corresponding toner storage portion through a replenishment pipe (replenishment path) 400.

  The toner image of each color on the photosensitive drum 1 is repeatedly primary-transferred for each color onto an intermediate transfer belt (hereinafter referred to as a belt) 5 which is an intermediate transfer member, and the toner image is transferred onto the belt 5. Synthetic formation. Thereafter, the toner image is secondarily transferred onto the recording material S in a lump and then fixed to output a full-color image formed product.

  This will be described in more detail below.

  The photosensitive drum 1 is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined speed, and the surface thereof is uniformly charged to a predetermined polarity and potential by a charger 2 as a charging device. The charged surface is subjected to laser scanning exposure by a laser scanner 3 as an exposure device.

  The laser scanner 3 includes a laser output unit, a polygon mirror, an imaging lens, a folding mirror, and the like. Then, laser light (optical signal) modulated in accordance with the image information signal input from the image processing unit is output to scan and expose the charged surface of the rotating photosensitive drum 1. As a result, an electrostatic image corresponding to the scanning exposure pattern is formed on the surface of the photosensitive drum 1.

  In addition to the image information read from the reading unit R described above, the image information signal may naturally be synthesized and formed from image information transmitted from an external device such as a personal computer.

  The electrostatic image is developed as a toner image by the developing device 50.

  As shown in FIG. 6, the rotary developing device as the developing means includes a plurality of developing devices 50 (50 b to 50 f) each containing a color developer containing toner of different colors with respect to a rotary 41 that is a rotating body. ) Is attached. Each held developer can move while rotating. The color developer includes a non-magnetic color toner and a magnetic carrier.

  As shown in FIG. 1, each developing device is switched to a developing position facing the photosensitive drum 1 by rotating the rotary 41 in one direction in the direction indicated by the arrow at a predetermined angle at a predetermined control timing. Is done. At the developing position, the distance between the photosensitive drum 1 and the developing sleeve on the developing device side is kept within a predetermined range.

  The belt 5 is an endless belt made of a dielectric material having flexibility, and is stretched around a plurality of rollers 5a to 5g. The outer surface of the belt 5 is in contact with the photosensitive drum 1 between the rollers 5b to 5c. The contact portion is a primary transfer nip portion T1.

  In the primary transfer nip T 1, a primary transfer member (transfer roller) 6 is disposed on the opposite side of the belt 5 from the photosensitive drum 1 side and is in contact with the inner surface of the belt 5.

  A primary transfer voltage having a polarity opposite to that of the toner is applied to the primary transfer roller 6 at a predetermined control timing. The belt 5 is rotationally driven in the clockwise direction indicated by an arrow at a speed substantially the same as the rotational speed of the photosensitive drum 1, for example, using the roller 5a as a driving roller.

  First, a toner image of the first color is formed on the photosensitive drum 1 by the above-described image forming process of charging / exposure / development. Then, the toner image is transferred onto the belt 5 at the primary transfer nip T1.

  The primary transfer residual toner that is not transferred to the belt 5 and remains on the surface of the photosensitive drum 1 is removed from the surface of the photosensitive drum by the drum cleaning device 7. The photosensitive drum 1 cleaned by the cleaning device 7 is repeatedly used for image formation.

  The same image forming process as described above is repeated as necessary for the second and subsequent colors. Thus, a toner image is formed on the belt 5 by sequentially superimposing and transferring the toner images of the development colors.

  On the other hand, at a predetermined control timing, the paper feed roller 11 of the paper feed unit selected in advance among the plurality of paper feed units of the first to fourth paper feed cassettes 81 to 84 or the manual feed tray 85 is driven. . As a result, the recording material S accommodated in the paper feeding unit is separated and sent out, and is sent from the sheet path 13 to the registration roller 14.

  The registration roller 14 controls the skew correction of the recording material S and the secondary transfer timing of the toner image from the belt 5 to the recording material S, and the leading edge of the recording material S fed from the paper feeding unit side. Receive and stop.

  Reference numeral 15 denotes a secondary transfer member (transfer roller). The secondary transfer roller 15 is disposed at a position where the belt 5 is sandwiched with respect to the roller 5g with the roller 5g among the plurality of rollers 5a to 5g of the belt 5 as an opposing roller. The secondary transfer roller 15 is switched between a first state in which the belt 5 is pressed against the belt 5 with a predetermined pressure and a second state in which the secondary transfer roller 15 is separated from the outer surface of the belt 5 by a pressure control mechanism (not shown). The

  The secondary transfer roller 15 is always switched and held in the second state separated from the outer surface of the belt 5. By switching to the first state, the secondary transfer nip portion T2 is formed between the outer surface of the belt 5 and the secondary transfer operation is executed.

  The secondary transfer roller 15 is switched to the first state at a predetermined control timing. Further, the recording material S that has been stopped at the position of the registration roller 14 is fed again from the registration roller 14 at a predetermined control timing. Then, the fed recording material S is introduced into the secondary transfer nip T2 between the secondary transfer roller 15 and the belt 5 that has been switched to the first state.

  The recording material S is nipped and conveyed through the secondary transfer nip portion T2. In the meantime, a predetermined secondary transfer voltage is applied to the secondary transfer roller 15, and the toner images composed of a plurality of colors on the belt 5 are electrostatically transferred onto the recording material S collectively.

  The secondary transfer residual toner that is not transferred to the recording material S and remains on the surface of the belt 5 is removed from the belt surface by the belt cleaning device 16. The belt 5 cleaned by the cleaning device 16 is repeatedly used for image formation.

  The cleaning device 16 is normally held in a state of being separated from the outer surface of the belt 5. When the secondary transfer of the toner image from the belt 5 to the recording material S is performed at the secondary transfer nip portion T2, the state is switched to the state in contact with the outer surface of the belt 5 at a predetermined control timing.

  The recording material S exiting the secondary transfer nip T2 is separated from the surface of the belt 5 and conveyed to the fixing device 18 by the conveying belt unit 17, and the unfixed toner image is fused on the recording material S by heat and pressure. A fixed image is formed. The recording material S that has exited the fixing device 18 passes through the sheet path 19 and is discharged onto the paper discharge tray 20.

  By the way, in the present image forming apparatus, it is difficult to increase the developer storage volume of the developing device 50 due to the limitation of the switching speed of the developing rotary 41 and the rotational driving torque.

  For this reason, the toner cartridges 2a, 2b, 2c, 2d, 2e, and 2f (FIG. 2) are arranged outside the developing rotary 41, and have been rotated to the developing position by the developing rotary 41 by their respective required amounts. The developer 50 is supplied. In this embodiment, each of the toner cartridges 2a to 2f is configured to have substantially the same function except that the color of the toner to be used is different. Therefore, unless otherwise specified, the toner cartridges 2a to 2f will be described as a toner cartridge 2 with the suffixes a to f omitted. Similarly, other configurations will be described with the subscripts omitted.

  Next, a toner replenishment path from the toner cartridge 2 to the toner receiving portion 120 (120a to 120f) serving as a replenishing port provided in the rotary developing device 41 will be described with reference to FIGS. FIG. 2 is a front view of the toner supply device 300 and the toner receiving unit 120 (120a to 120f), and FIG. 3 is a bottom view of the toner supply device 300.

  A toner replenishing device 300 as toner replenishing means is provided above the toner receiving portion 120 and on the front side of the image forming apparatus. Further, the toner replenishing device 300 includes a toner cartridge 2 (2a to 2f), a replenishing unit 130, and a replenishing pipe 140 as shown in FIG. The toner cartridge 2 is detachably accommodated in the replenishment unit station (150a to 150f).

  The toner contained in the toner cartridges (2a to 2f) is detected from the replenishment port below the toner cartridge 2 until the toner sensor detects toner when a toner sensor (not shown) detects the absence of toner in the replenishment unit 130. The replenishment units (130a to 130f) are appropriately replenished. The replenishment unit 130 (130a to 130f) stores a certain amount of toner. When a toner supply signal is received from the image forming apparatus, the toner is discharged from the supply port 200 in the supply unit 130 to the supply pipe 140 by a predetermined amount while the development rotary is stopped at the development position.

  The conveying screw in the replenishing pipe 140 as a conveying path is driven by the same driving source as a driving source (not shown) that drives the conveying screw of the replenishing unit 130. The supply pipe 140 receives toner from the supply unit 130 and discharges the toner to the toner receiving unit 120.

  The replenishment pipe 140 as a conveyance path is driven by the same drive (not shown) as the replenishment unit 130, receives toner from the replenishment unit 130, and discharges the toner to the toner receiving unit 120.

  The toner receiving unit 120 is provided on the front side of the developing rotary 41, and has six supply ports partitioned so as to be arranged in the back and front directions as shown in FIG. Each supply port is provided in a conveyance path (first conveyance path) communicating with the developing device 50 (50b to 50f) provided in the development rotary 41. In this embodiment, the toner receiving ports 120 as the toner receiving portions for the respective colors are arranged in order of transparent 120b, yellow 120c, magenta 120d, cyan 120e, and black 120f from the back side of the image forming apparatus. In this embodiment, since it is used as an image forming apparatus corresponding to five colors, 150a is an empty station and 120a is not used.

  Further, since the developing rotary 41 is a rotary developing method, it can receive toner only in the posture of the developing position (or some specific one position). For this reason, the replenishing operation is sequentially repeated as the developing rotary rotates for each color.

  In the developing rotary 41, as shown in FIG. 1, a plurality of supply paths (supply pipes) 400 (400b to 400f) for receiving and transporting the toner to each developing device are configured.

  Hereinafter, the toner supply unit and the toner supply path to the developing device 50 will be described in detail with reference to FIGS. 7, 8, 9, and 10. FIG. 7 is an upper perspective view of the developing rotary portion and the toner supply port portion with the developing device 50 mounted thereon.

  The developing rotary unit includes a rear plate unit 430, a front plate unit 440, and a connecting stay unit 450, and is supported by a full color image forming apparatus main body by a flange (not shown) mounted on the front and rear plates.

  The drive gear 805 is rotationally driven by a rotary motor gear 804 mounted on a rotary drive motor 802 mounted on the image forming apparatus main body frame side, and switches the developing devices 50 (50b to 50f). It has become.

  The rotary drive motor 802 needs to ensure that the switching of the developing device 50 (50b to 50f) is performed at a high speed in a short time of about 200 msec and the rotation angle with high accuracy, and the posture is maintained at the developing device stop position. Because it is necessary to use a stepping motor.

  On the front side of the developing rotary unit, a toner receiving unit portion having fixing flanges 220b to 220f provided with toner receiving ports 120b to 120f is disposed on the front side of the apparatus main body. Further, the toner sent from an external toner cartridge (not shown) is received by the toner receiving ports 120b to 120f for each color.

  FIG. 8 is a cross-sectional view of the toner receiving unit 120.

  This drawing is a cross-sectional view of the clear toner replenishment path portion in a state where the clear developing device 50b is in the developing position. The toner receiving portion 120b is provided on the fixed flange 220b, and a cylindrical rotating drum 40b that rotates integrally with the developing rotary 41 is provided inside the fixed flange 220b. The toner transport unit 400b is a toner transport unit that transports toner to the developing device 50b, and a screw that transports toner is disposed therein. As shown in FIG. 8, the toner receiving unit 120, the rotating drum 40, and the toner transport unit 400 are connected as a path only when in the development position. As a result, it is shown that the toner received by the toner receiving unit 120b can be transferred to the conveying screw unit 400b. As described above, the conveying screw for conveying the toner is arranged inside the supply path 400 (400b to 400f) provided in the rotary 41. The replenishment path 400 is configured to convey each color toner to each of the transparent developer and the plurality of colored developers by being connected to each of the transparent developer and the plurality of colored developers.

  Next, toner movement will be described in detail.

  As shown in FIG. 8, the toner received at the toner receiving port 120b drops and moves to the opening 1400b to the toner conveying path 400b including the toner conveying screw for conveying the toner to the developing device 50b. That is, the replenishment toner is dropped and replenished from the upper side in the gravity direction. The toner dropped into the opening 1400b is transferred from the toner receiving port 120b to the toner conveyance path 400b via the toner replenishment space 410b in the downward direction of gravity, and is conveyed toward the corresponding developing device. .

  As shown in the drawing, only when the developing rotary is at this angle, the toner receiving portion 120b and the conveying screw portion 400b are connected in the direction of gravity (vertical direction). It can be seen that the toner is dropped from above and is conveyed to the developing unit.

  Since the cylindrical rotating drum 40b rotates integrally with the rotary in the direction of the arrow R in the figure, the rotating drum 40b is provided with a wall 141b for preventing the backflow of toner and a collection wall 142b for scooping out the leaked toner. Yes. All the toner supplied from the toner cartridge 2 is sent to the developing device.

  FIG. 9 is a diagram (perspective view) showing an excerpt of the part related to the toner transport means (toner transport unit) in the developing rotary described above.

  The toner conveying means includes the above-described cylindrical rotating drum 40b and a toner conveying portion 400b including a toner conveying screw for conveying toner to the developing device 50b.

  As described above, the toner conveyed from the toner cartridge 2 is conveyed to the toner receiving unit 120 in FIG. Then, when the developing rotary 41 is rotated, the toner is dropped and supplied when the opening provided in the rotary drum 40b is directed upward.

  As can be seen from FIG. 9, since the toner that has fallen is transported to the developing device 50b, the toner transporting portion 400b is disposed inside the cylinder of the rotating drum 40b and rotated together with the developing device. It is.

  The rotating drum 40b has a configuration in which an opening portion is directed directly above when the developing device 50b is at the developing position (image forming position), and only toner of a developed color can be supplied and supplied during development. Yes.

  FIG. 10 is a cross-sectional view illustrating a toner transport unit and a toner delivery unit to the developing device in the embodiment of the present invention. As shown in FIG. 10, the toner transport unit 400 (400b to 400f) is provided with an opening (toner delivery unit) in accordance with the replenishment receiving opening 410 (410b to 410f) of the developing device 50 (50b to 50f). It has been. Here, the toner is supplied to the developing device using gravity.

  The toner delivery portion is sealed by a sponge-like seal member 420b so that the toner does not leak outside. The replenished toner is conveyed to the developing position by a developing roller 430b as a developer carrying member facing the photosensitive drum 1, and contributes to development.

  A transfer cleaner 16 is disposed close to the developing rotary 41 below the gravitational direction.

  Hereinafter, a detailed description will be given of a toner replenishment configuration from the toner replenishing device 300 to each of the developing devices 50b to 50f, which is a form of toner color mixing countermeasures in the image forming apparatus of the present embodiment, with reference to the detailed drawings.

  In this embodiment, the arrangement of the toner receiving units 120b to 120f is determined so that the other colors are difficult to mix or the influence of the image is reduced even if the colors are mixed.

  FIG. 6 is a perspective view of the developing rotary 41, and the toner receiving portions 120b to 120f are arranged in a predetermined direction (the rotational axis direction of the developing rotary 41). The plurality of conveyance paths 400 provided for conveying the toner to each developing device 50 are provided with toner receiving portions 120 (120b to 120f) as replenishment ports for replenishing each color toner. ing. (FIG. 4) As will be described in detail later, in the present embodiment, among the plurality of toner receiving portions 120b to 120f, the transparent toner receiving portion 120b is positioned so that it is at the end in the arrangement direction. This reduces the risk of color mixing.

  Hereinafter, description will be made with reference to FIGS. 4, 5, and 6.

  FIG. 5 is a perspective view of the toner replenishing device 300. The toner replenishing device 300 has six spaces which are replenishment unit stations (15a to 15f). In the replenishment unit station 15, toner cartridges (2a to 2f) and replenishment units (13a to 13f) are detachably provided. Further, the toner replenishing device 300 is detachably held on the upper front side of the image forming apparatus so that the development rotary 41 can be maintained.

  FIG. 6 is a perspective view of the developing rotary 41, and the developing rotary 41 has six spaces which are developing device stations 160 (160a to 160f). Developer units (50a to 50f) are detachably provided in the developer station 160.

  When the image forming apparatus uses five colors of yellow, magenta, cyan, black, and transparent, the transparent developing device 50b is attached to the transparent developing station 160b among the six developing stations 160. Further, a yellow developing device 50c is attached to the yellow developing station 160c, and a magenta developing device 50d is attached to the magenta developing station 160d. A cyan developing device 50e is attached to the cyan developing station 160e, and a black developing device 50f is attached to the black developing station 160f.

  FIG. 4 is a perspective view of the toner receiving unit 120, and toner is supplied to each toner receiving unit via a toner conveyance path from the developing device 50 to the toner receiving unit 120. The toner receiving unit 120 is arranged as a transparent toner receiving unit 120b, a yellow toner receiving unit 120c, a magenta toner receiving unit 120d, a cyan toner receiving unit 120e, and a black toner receiving unit 120f.

  As a result, the color order of the replenishment pipe 140 is determined, and the color order of the replenishment unit station 150 in the toner replenishing device 300 is also the color order of 150b is transparent, 150c is yellow, 150d is magenta, 150e is cyan, and 150f is black. Become.

  In the five-color image forming apparatus, 150a becomes an empty station and is not used, and the toner receiving unit 120a is not used.

  As described above, since the replenishment unit station 150 of the toner replenishing device 300 is determined depending on how the developing device 50 is attached to the developing rotary 41, various arrangements can be considered. In the present embodiment, the arrangement of the replenishment unit stations 15b to 15f is determined so as to realize an arrangement configuration that is not affected even when a plurality of colored toners are mixed with the transparent toner.

  Next, it will be described that other color toners can be prevented from being mixed when the toner replenishing device 300 is separated from the toner receiving unit 120 during maintenance of the developing device.

  In this embodiment, the toner supply device 300 can be separated from the toner receiving unit 120 during maintenance of the developing device. FIG. 11A is a diagram when the toner replenishing device 300 is separated from the toner receiving unit 120, and FIG. 11B is a diagram when the toner replenishing device 300 is attached to the toner receiving unit 120. FIG. 11 is a diagram viewed from the left side (left side surface of the apparatus) of FIG.

  As shown in FIG. 11, the toner replenishing device 300 is configured to be slidably supported on the front side of the device (in the arrow direction in FIG. 11) in order to improve workability. Therefore, at the time of maintenance, the discharge port of the plurality of colored toner supply pipes 140 of the toner conveying device 300 located at the upper part of the toner receiving part 120 crosses the upper side of the toner receiving part 120 located at the lower part. For example, in the case of the toner receiving unit 120f arranged on the front side of the apparatus, the discharge ports of the toner replenishing pipes for all colors pass above the toner receiving unit 120f, so the risk of color mixing is the highest. Therefore, in this embodiment, the transparent toner receiving unit 120b is provided on the back side of the apparatus. That is, the transparent toner receiving unit 120b is disposed outside the region projected downward in the direction of gravity with respect to the movement locus of the discharge port of the plurality of colored toner supply pipes 140. With this configuration, even when toner drops from the plurality of colored toner supply pipes 140 when the toner supply device 300 slides, color mixing can be suppressed as much as possible. Further, in the present embodiment, the transparent toner receiving portion 120b is provided so as to be disposed at the end among the plurality of toner receiving portions 120b to 120f arranged side by side. For this reason, it is possible to reduce the risk of mixing other color toners from adjacent toner receiving portions.

  In this embodiment, the toner receiving unit of another color adjacent to the transparent toner receiving unit 120b is a yellow toner receiving unit 120c that transfers yellow toner. In this way, even if the toner is mixed from the adjacent transfer unit, the image influence is small.

  This makes use of the fact that the human eye has a weak identification ability for images drawn with yellow toner.

(Example 2)
In this embodiment, the configuration is almost the same as that of the first embodiment, and only different portions will be described. In the first exemplary embodiment, the toner receiving unit 120b for transparent toner is disposed adjacent to the toner receiving unit for yellow toner. In this embodiment, a toner receiving unit 120 for black toner is provided adjacent to the toner receiving unit 120b for transparent toner instead of the toner receiving unit for yellow toner. This is because the human eye has a weak ability to distinguish density differences (color differences).

  According to the experiment by the inventors, 0.25% of magenta, cyan and black toners were mixed in a certain amount of transparent toner, the transparent toner was set to 0, and the color difference (ΔE) was measured.

  As a color measurement method, recording material Oji Paper Co., Ltd. SA Kinfuji + was used, and a solid image was drawn and measured.

  As a result, yellow 1.23, magenta 0.67, cyan 0.55, and black 0.36. From this, it was found that the influence on the image is the least when black toner is mixed.

  As described above, in this embodiment, by paying attention to the color difference with respect to the transparent toner, even if the toner is mixed from the adjacent toner receiving portion, the influence of the color mixture can be suppressed.

  As described above, the image forming apparatus of the present invention has been described by the two embodiments. However, the present invention is not limited to the above-described configuration, and according to the proposal of the present invention by adopting a separation method that does not cause color mixture in the transparent toner. Various configurations are possible.

1 is a main cross-sectional view of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a front view of a toner conveying unit according to the embodiment of the present invention. FIG. 6 is a bottom view of the toner conveying device according to the embodiment of the present invention. 1 is a perspective view of a toner supply unit according to an embodiment of the present invention. FIG. 3 is a perspective view of a toner conveying unit according to an embodiment of the present invention. The perspective view of the image development rotary in embodiment of this invention The perspective view which showed the circumference | surroundings of the image development rotary of this invention embodiment Sectional view when the developing rotary toner can be replenished according to the embodiment of the present invention The perspective view showing the toner replenishment path | route to the developing device of this embodiment. Sectional drawing which showed the toner conveyance part and toner receiving part to a developing device in embodiment of this invention FIG. 6 is a side view of the developing rotary when the toner supply device according to the embodiment of the present invention is attached to and detached from the toner receiving unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Toner cartridge 300 Toner conveyance apparatus 41 Developing rotary 50 Developer 120 Toner supply part 130 Supply unit 140 Supply pipe 150 Supply unit station 160 Developer station 200 Supply port

Claims (4)

An image carrier;
A transparent developer for developing the electrostatic image formed on the image carrier with a transparent toner;
A plurality of color developing devices that respectively develop the electrostatic images formed on the image carrier with colored toner;
A plurality of transport paths for transporting toner to each of the transparent developer and the plurality of colored developers by being connected to each of the transparent developer and the plurality of colored developers;
A plurality of replenishing ports that are provided in each of the plurality of transport paths and receive the corresponding toner, and are provided so as to be separated from each of the plurality of replenishing ports, and correspond to each of the plurality of replenishing ports. A replenishing device for replenishing toner,
An image forming apparatus having
The plurality of replenishing ports are arranged so as to be adjacent to each other, and among the plurality of replenishing ports, the replenishing ports provided in the transport path to the transparent developing unit are end portions in the arrangement direction. are arranged to,
The replenishing device is connected to each of the plurality of replenished ports on the upper side in the direction of gravity, and has a plurality of replenishing ports for discharging the corresponding toner to each of the plurality of replenished ports, When a plurality of supply ports are separated from the plurality of supply ports, an area in which a movement trajectory of the supply port provided in the conveyance path to the color developer is projected downward in the gravitational direction. outside, the image forming apparatus, wherein said Rukoto have the supply port is provided, which is provided in the transport path of the the transparent developing unit.   The plurality of color developing devices include at least a yellow developing device that develops with yellow toner, and a replenishing port adjacent to a replenishing port provided in a transport path to the transparent developing device includes the yellow developing device. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a replenishing port provided in a conveyance path to the developing unit.   The plurality of color developing devices include at least a black developing device that develops with black toner, and a replenishing port adjacent to a replenishing port provided in a transport path to the transparent developing device includes the black developing device. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a replenishing port provided in a conveyance path to the developing unit. A rotating body that holds the transparent developing unit and the plurality of colored developing units, respectively, and is capable of moving the transparent developing unit and the plurality of colored developing units toward a developing position facing the image carrier. The image forming apparatus according to claim 1, wherein the plurality of transport paths are supported by the rotating body .

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