Image forming apparatus

Abstract

This design prevents the toner transport path from obstructing the optical path while contributing to the miniaturization of the image forming apparatus. [Solution] An image forming apparatus wherein the second photosensitive drum is positioned between the first toner container and the first developing container in a first direction, a portion of the first pipe is provided to pass through an area outside the optical path of the laser light irradiated from the laser scanner to the second photosensitive drum in a second direction, and at least a portion of the wall is provided to be in the area between the portion of the first pipe and the optical path in the second direction, and to overlap with the optical path when viewed in the direction of the rotation axis of the second photosensitive drum.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus and a toner container used therefor.

Background Art

[0002] In an electrophotographic image forming apparatus, a configuration is known in which a toner container that is detachable from the image forming apparatus is used to supply toner to a developing container in the image forming apparatus. For example, Patent Document 1 discloses a configuration in which a toner container is attached to the front side of the image forming apparatus, that is, the side where the user is located, and the user supplies toner, and the toner supplied to the toner container is conveyed to the developing container by a screw.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If the toner conveyance path connecting the toner container and the developing container has a flexible configuration, there is a risk that the deformed toner conveyance path based on its flexibility may block the optical path, which is the path of light emitted from the light emitting unit. Further, if the toner conveyance path and the optical path are arranged far apart so that the toner conveyance path does not block the optical path, there is a risk that the image forming apparatus will become large-sized. Therefore, an object of the present invention is to solve such problems and contribute to downsizing of the image forming apparatus while preventing the toner conveyance path from blocking the optical path.

Means for Solving the Problems

[0005] To solve the aforementioned problems, the configuration of the image forming apparatus of the present invention is a first developing unit having a laser scanner, a first photosensitive drum on which an electrostatic latent image is formed when laser light is irradiated by the laser scanner and the first photosensitive drum is configured to be rotatable, a second photosensitive drum on which an electrostatic latent image is formed when laser light is irradiated by the laser scanner and the second photosensitive drum is aligned with the first photosensitive drum in a first direction intersecting the direction of gravity, a first developing roller that supplies first toner to the first photosensitive drum and develops a first toner image, and a first developing container that contains the first toner to be carried on the first developing roller, a second developing unit having a second developing roller that supplies second toner to the second photosensitive drum and develops a second toner image, and a second developing container that contains the second toner to be carried on the second developing roller, a first toner container that contains the first toner to be replenished in the first developing container, and a second toner container that contains the second toner to be replenished in the second developing container. The second photosensitive drum is characterized in that it is positioned between the first toner container and the first developer container in the first direction, a portion of the first pipe is provided so as to pass through the region outside the optical path of the laser light irradiated from the laser scanner to the second photosensitive drum in the second direction, and at least a portion of the wall is provided so as to pass through the region between the portion of the first pipe and the optical path in the second direction, and overlaps with the optical path when viewed in the direction of the rotation axis of the second photosensitive drum. [Effects of the Invention]

[0006] As described above, according to the present invention, the toner transport path connecting the toner container and the developing container is flexible, which prevents the optical path of the light emitted from the light-emitting unit from being obstructed, and in turn contributes to miniaturization of the main unit. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cross-sectional view of a characteristic image forming apparatus according to the present invention. [Figure 2] This is a cross-sectional view of the entire image forming apparatus according to the first embodiment. [Figure 3] This is a perspective view of the entire image forming apparatus according to the first embodiment. [Figure 4] This is a perspective view of the image forming unit according to the first embodiment. [Figure 5] This is a top view of an image forming unit according to the first embodiment. [Figure 6] This is a cross-sectional view of an image forming unit according to the first embodiment. [Figure 7] These are a cross-sectional view and an enlarged cross-sectional view parallel to the optical path of the image forming unit according to the first embodiment. [Figure 8] This is a cross-sectional view of a process unit according to the first embodiment. [Figure 9] The first embodiment is shown as a top view of the image forming unit. [Figure 10] These are a cross-sectional view and an enlarged cross-sectional view parallel to the optical path of the image forming unit according to the first embodiment. [Figure 11] This is a perspective view of another embodiment of the image forming unit according to the first embodiment. [Figure 12] This is a perspective view of another embodiment of the image forming unit according to the first embodiment. [Figure 13] This is a cross-sectional view of the image forming unit according to the second embodiment, taken in the withdrawal direction. [Figure 14] This is a perspective view of the image forming unit according to the second embodiment. [Modes for carrying out the invention]

[0008] <First Embodiment> (Image forming apparatus) An image forming apparatus 1 according to the first embodiment of the present invention will be described with reference to Figure 2. The electrophotographic image forming apparatus of this embodiment is a full-color image forming apparatus equipped with four color process units. Figure 2 is a main cross-section of the image forming apparatus 1.

[0009] Image forming apparatus 1 is a full-color laser printer using an electrophotographic process, and is capable of forming full-color images on a recording medium S. Image forming apparatus 1 comprises process units PY, PM, PC, and PK (hereinafter referred to as each process unit P) and a main body 72. Each process unit P is arranged to align in a first direction X (first direction), which is a horizontal direction parallel to the ground surface of the image forming apparatus 1. Each process unit P contains a different color of toner. The toner color of process unit PY is yellow. Similarly, the toner color of process unit PM is magenta. In the following description, the toner color of process unit PC is cyan. The toner color of process unit PK is black. The suffix of the code represents the initial letter of the toner color, and this is the same for other codes as well.

[0010] The longitudinal direction of process unit P is the second direction Y (second direction), which is perpendicular to the first direction. Direction Y is a horizontal direction parallel to the ground surface of the image forming apparatus 1, just like the first direction. Process units PY, PM, PC, and PK are designated as the first process unit, second process unit, third process unit, and fourth process unit, respectively.

[0011] Each process unit P has elements used in the electrophotographic process. Rotational driving force is transmitted to the process unit P from the drive output section (not shown) of the main body 72 of the apparatus. In addition, the process unit P is supplied with a bias voltage (charging bias, development bias, etc.) from the bias application section (not shown) of the main body 72 of the apparatus.

[0012] As shown in FIG. 2, each process unit P includes drum units 8Y, 8M, 8C, 8K (hereinafter, the symbols indicating the toner colors are omitted and each drum unit is denoted as 8. The same applies to other units), and developing units 9Y, 9M, 9C, 9K (hereinafter, each developing unit is denoted as 9). The drum units 8Y, 8M, 8C, 8K are respectively referred to as the first drum unit, the second drum unit, the third drum unit, and the fourth drum unit.

[0013] Each drum unit 8 has a photosensitive drum 4Y, 4M, 4C, 4K (hereinafter, each photosensitive drum is denoted as 4), and charging rollers 5Y, 5M, 5C, 5K (hereinafter, each charging roller is denoted as 5) as process means acting on each photosensitive drum 4. Each photosensitive drum 4 is rotatably arranged such that the direction of their rotation axes (first rotation axes) is in the second direction Y. The photosensitive drums 4Y, 4M, 4C, 4K are respectively referred to as the first photosensitive drum, the second photosensitive drum, the third photosensitive drum, and the fourth photosensitive drum.

[0014] Each developing unit 9 has developing rollers 6Y, 6M, 6C, 6K (hereinafter, each developing roller is denoted as 6) for developing an electrostatic latent image on the corresponding photosensitive drum 4. Each developing unit 9 is aligned in the first direction X. The developing rollers 6Y, 6M, 6C, 6K are respectively the first developing roller, the second developing roller, the third developing roller, and the fourth developing roller. The developing units 9Y, 9M, 9C, 9K are respectively the first developing unit, the second developing unit, the third developing unit, and the fourth developing unit.

[0015] The developing unit 9Y has a developing container 3Y (first developing container) for storing yellow (Y) toner (first toner), and is configured such that yellow (Y) toner is supplied to the surface of the photosensitive drum 4Y by the developing roller 6Y carrying the yellow (Y) toner.

[0016] The developing unit 9M has a developing container 3M (second developing container) that contains magenta (M) toner (second toner), and is configured so that magenta (M) toner is supplied to the surface of the photosensitive drum 4M by a developing roller 6M that carries the magenta (M) toner.

[0017] The developing unit 9C has a developing container 3C (third developing container) that contains cyan (C) toner (third toner), and is configured so that cyan (C) toner is supplied to the surface of the photosensitive drum 4C by a developing roller 6C that carries the cyan (C) toner.

[0018] The developing unit 9K has a developing container 3K (fourth developing container) that contains black (K) toner (fourth toner), and is configured so that the black (K) toner is supplied to the surface of the photosensitive drum 4K by a developing roller 6K that carries the black (K) toner.

[0019] In a third direction Z (third direction) that intersects both the first direction X and the second direction Y, a laser scanner unit LB (exposure unit, laser scanner) is provided above the process unit P (photosensitive drum 4). The third direction Z is the direction of gravity perpendicular to the ground surface of the image forming apparatus 1.

[0020] This laser scanner unit LB outputs laser light corresponding to the image information. Hereafter, the optical paths of the laser light directed to each photosensitive drum 4Y, 4M, 4C, and 4K will be referred to as optical path LY (first optical path), LM (second optical path), LC (third optical path), and LK (fourth optical path) respectively (hereinafter referred to as each optical path L or optical path L).

[0021] The laser beam directed towards photosensitive drum 4Y is designated as the first laser beam. The path taken by the first laser beam is the first optical path. The laser beam directed towards photosensitive drum 4M is designated as the second laser beam. The path taken by the second laser beam is the second optical path. The laser beam directed towards photosensitive drum 4C is designated as the third laser beam. The path taken by the third laser beam is the third optical path. The laser beam directed towards photosensitive drum 4K is designated as the fourth laser beam. The path taken by the fourth laser beam is the fourth optical path.

[0022] The deflected and scanned laser beam passes through the exposure windows 10Y, 10M, 10C, and 10K of the laser scanner unit LB and irradiates the surface of each photosensitive drum 4. Note that an LED exposure unit may be used instead of the laser scanner unit LB.

[0023] In the third direction Z, an intermediate transfer belt unit 11 is provided below the process unit P as a transfer member. This intermediate transfer belt unit 11 has a drive roller 14, a tension roller 13, and an assist roller 15, and a flexible transfer belt 12 is stretched across it.

[0024] Each photosensitive drum 4 has its lower surface in contact with the upper surface of the transfer belt 12. The contact area between each photosensitive drum 4 and the transfer belt 12 is the primary transfer section 30Y, 30M, 30C, 30K (hereinafter referred to as the primary transfer section 30). Inside the transfer belt 12, there are primary transfer rollers 16Y, 16M, 16C, 16K (hereinafter referred to as the transfer rollers 16) that face the photosensitive drum 4.

[0025] The secondary transfer roller 17 is pressed against the drive roller 14 via the transfer belt 12. The contact area between the transfer belt 12 and the secondary transfer roller 17 is the secondary transfer section 31.

[0026] In the third direction Z, a feeding unit 18 is provided below the intermediate transfer belt unit 11. The feeding unit 18 includes a paper feed tray 19 for loading and storing recording media S, and a paper feed roller 20 for picking up and transporting the recording media S from the paper feed tray 19.

[0027] In Figure 2, the upper part of the main body 72 of the device is provided with a fixing unit 21 for fixing the toner image onto the recording medium S, and an discharge roller 22 for discharging the recording medium S with the toner image fixed onto it to the discharge tray 23. The discharge roller 22 discharges the recording medium S in a direction roughly aligned with the first direction X.

[0028] In this embodiment, in the first direction X, the downstream side of the discharge direction in which the recording medium S is discharged toward the discharge tray 23 by the discharge roller 22 is the front side of the image forming apparatus 1, and the upstream side of the discharge direction is the rear side of the image forming apparatus 1.

[0029] (Image formation process) The image forming operation for creating a full-color image is as follows: Each photosensitive drum 4 is driven to rotate at a predetermined speed in a counterclockwise direction in Figure 2. The transfer belt 12 is driven to rotate in the forward direction of the rotation of each photosensitive drum 4 (in the direction of arrow C in Figure 2) at a speed corresponding to the rotation speed of each photosensitive drum 4.

[0030] The laser scanner unit LB is also driven. Synchronized with the driving of the laser scanner unit LB, each charging roller 5 (5Y, 5M, 5C, 5K) in each process unit P uniformly charges the surface of the corresponding photosensitive drum 4 to a predetermined polarity and potential.

[0031] The laser scanner unit LB scans and exposes the surface of each charged photosensitive drum 4 with laser light according to the image signal of each color, forming an electrostatic latent image on the surface of each photosensitive drum 4 corresponding to the image signal of each color.

[0032] In other words, the laser scanner unit LB exposes the photosensitive drum 4Y and forms a first electrostatic latent image (first toner image) on each of the photosensitive drums 4Y. Similarly, the laser scanner unit LB exposes the photosensitive drums 4M, 4C, and 4K. Then, the laser scanner unit LB forms a second electrostatic latent image (second toner image), a third electrostatic latent image (third toner image), and a fourth electrostatic latent image (fourth toner image) on each of the photosensitive drums 4M, 4C, and 4K, respectively.

[0033] The electrostatic latent image on each photosensitive drum 4 is developed by supplying toner to each photosensitive drum 4 by each developing roller 6, which is driven to rotate clockwise at a predetermined speed as shown in Figure 2.

[0034] As described above, the electrophotographic image formation process forms a yellow toner image on the photosensitive drum 4Y of process unit PY. This yellow toner image is then primary transferred onto the transfer belt 12. Similarly, a magenta toner image is formed on the photosensitive drum 4M of process unit PM. This magenta toner image is then primary transferred onto the transfer belt 12 so as to be superimposed on the yellow toner image on the transfer belt 12. A cyan toner image is also formed on the photosensitive drum 4C of process unit PC. This cyan toner image is then primary transferred onto the transfer belt 12 so as to be superimposed on the yellow and magenta toner images on the transfer belt 12. Similarly, a black toner image is formed on the photosensitive drum 4K of process unit PK. This black toner image is then primary transferred onto the transfer belt 12 so as to be superimposed on the yellow, magenta, and cyan toner images on the transfer belt 12.

[0035] In this way, a full-color, unfixed toner image of four colors—yellow, magenta, cyan, and black—is formed on the transfer belt 12. Meanwhile, at a predetermined control timing, the recording media S are separated one by one from the paper tray 19 by the paper feed roller 20 and fed. The recording media S are then transported at a predetermined control timing to the secondary transfer section 31, which is the contact point between the secondary transfer roller 17 and the transfer belt 12. As the recording media S is transported in the secondary transfer section 31, the four-color superimposed toner image on the transfer belt 12 is transferred to the recording media S. The recording media S on which the toner image has been transferred is heated and pressurized by the fixing unit 21, and the toner image is fixed to the recording media S. The recording media S on which the toner image has been fixed is then discharged to the discharge tray 23 by the discharge roller 22.

[0036] (Removable cartridge) The image forming apparatus 1 has cartridges 430Y, 430M, 430C, and 430K (hereinafter, each cartridge 430) that can be attached to the apparatus body 72. Each cartridge 430 is aligned in the second direction Y. That is, each cartridge 430 is aligned in a direction intersecting the direction in which each developing unit 9 is aligned. Cartridges 430Y, 430M, 430C, and 430K are referred to as the first cartridge (first toner container), the second cartridge (second toner container), the third cartridge (third toner container), and the fourth cartridge (fourth toner container), respectively.

[0037] Figure 3(a) is a perspective view of the image forming apparatus 1 with the front door 72b closed. Figure 3(b) is a perspective view of the image forming apparatus 1 with the front door 72b open. Figure 3(c) is a perspective view of the image forming apparatus 1 with the front door 72b open and the cartridge 430M removed from the cartridge holder 429.

[0038] Each cartridge 430 is mounted on the upper front side of the main body 72 so that it can be accessed by opening the front door 72b. In other words, each cartridge 430 is located at the downstream end of the main body 72 in the discharge direction of the recording medium S discharged by the discharge roller 22. The front door 72b is configured to move between a closed position (see Figure 3(a)) that closes the opening E of the front side of the main body 72 and an open position (see Figure 3(b)) that opens the opening E. When the front door 72b is moved to the open position, each cartridge 430 is exposed to the outside of the image forming apparatus 1 through the opening E, as shown in Figure 3(b). Each cartridge 430 is arranged in a second direction Y and is configured to be detachable from the main body 72 in a first direction X, as shown in Figure 3(c). The first direction X and the second direction Y are orthogonal to each other. This allows toner to be supplied to each process unit P without detaching each process unit P from the main body 72. Since each cartridge 430 is positioned on the front side of the image forming apparatus 1, each cartridge 430 can be accessed from the front side, similar to how the recording medium S discharged into the discharge tray 23 is retrieved. Furthermore, because there is a cartridge holder 429 on the front side of the image forming apparatus 1 that holds each cartridge 430, the process unit P is not exposed even after each cartridge 430 is removed (see Figure 3(c)). Each cartridge 430 is housed inside the apparatus body 72 when the front door 72b is closed.

[0039] As shown in Figure 3(a), indicators 208Y, 208M, 208C, and 208K (hereinafter referred to as indicators 208; they may also be called indicator units or display units) of each color are provided on the front of the image forming apparatus 1. Each indicator 208 is arranged in the second direction Y to correspond to each cartridge 430. Indicator 208Y (first indicator) is yellow, indicator 208M (second indicator) is magenta, indicator 208C (third indicator) is cyan, and indicator 208K (fourth indicator) is black. Each indicator 208 consists of an LED or sticker of the color corresponding to the toner color of each cartridge. They are provided to show the user which toner color cartridge should be installed to prevent incorrect installation of each cartridge 430. In addition, each indicator 208 may also have a toner level display function for the corresponding process unit P (each developing unit 9).

[0040] (Toner transport) The toner transport mechanism from each cartridge 430 to each corresponding process unit P will be explained using Figures 4 to 6.

[0041] An image forming unit 500 is defined as a unit that includes each cartridge 430, each process unit P, and a transport path for transporting toner from each cartridge 430 to each process unit P, and is configured to hold these components together as a single unit.

[0042] Figure 4(a) is a perspective view of the image forming unit 500 with each cartridge 430 installed. Figure 4(b) is a perspective view of the image forming unit with each cartridge 430 removed. Figure 5 is a top view of the image forming unit 500. Figures 6(a) and 6(b) are cross-sections AA and BB of Figure 5, respectively.

[0043] As shown in Figure 4(a), pump units 80Y, 80M, 80C, and 80K (hereinafter referred to as each pump unit 80) are provided below the cartridge holder 429. Each pump unit 80 is aligned in the second direction Y. Pump units 80Y, 80M, 80C, and 80K are designated as the first pump unit, second pump unit, third pump unit, and fourth pump unit, respectively. Each pump unit 80 uses a positive displacement pump, such as a reciprocating pump or a rotary pump. A reciprocating pump is a pump that performs suction and discharge by the reciprocating motion of a piston or plunger. Types of reciprocating pumps include piston pumps, plunger pumps, and diaphragm pumps. A rotary pump is a pump that performs suction and discharge by the rotational motion of gears or a rotor. Types of rotary pumps include gear pumps, screw pumps, and vane pumps. Note that the four pump units may be configured as a single pump unit. Furthermore, although each pump unit 80 is provided on the main body 72 of the device in this embodiment, it may also be provided on each cartridge 430.

[0044] As shown in Figure 4(b), each pump unit 80 is arranged in the cartridge holder 429 opposite the lower surface of each cartridge 430, and is configured to increase or decrease air pressure and move the air. An opening is provided that exposes the discharge ports 80Ya, 80Ma, 80Ca, and 80Ka (hereinafter referred to as each discharge port 80a) from which the air generated by each pump unit 80 is discharged. Each discharge port 80a opens upward. The air discharged upward from each discharge port 80a is supplied to each cartridge 430 mounted in the cartridge holder 429.

[0045] Next, we will explain how the air supplied to each cartridge 430 is transported to each developing unit 9 along with the toner, using Figure 6(a).

[0046] Here, Figure 6(a) describes cartridge 430Y, but cartridges 430M, 430C, and 430K are similar. Therefore, explanations for colors other than yellow are omitted here. Cartridge 430 is equipped with a mesh-like filter 83Y configured to allow air to pass through but not toner. Air supplied from the discharge port 80Ya passes through the filter 83Y and mixes with the toner. The toner, along with the air, passes through the discharge pipe 85Y (passage) formed inside cartridge 430Y and is discharged outside cartridge 430Y from the discharge port 430Ya1 of cartridge 430Y.

[0047] The toner discharged from each cartridge 430 is received along with air through the receiving ports 429Ya, 429Ma, 429Ca, and 429Ka (hereinafter referred to as each receiving port 429a) provided in the cartridge holder 429 shown in Figure 4(b), into the replenishment pipes 444Y (first toner transport path, first transport path, first pipe), 444M (second toner transport path, second transport path, second pipe), 444C (third toner transport path, third transport path, third pipe), and 444K (fourth toner transport path, fourth transport path, fourth pipe) (hereinafter referred to as each replenishment pipe 444).

[0048] Each supply pipe 444 extends from each cartridge 430 to each developing unit 9 and is made of a material that is flexible enough to transport toner and has excellent toner resistance. For example, a tube made of polyurethane, silicone, nylon, or polyolefin is preferable because it can be constructed as a flexible tube that can change shape.

[0049] Each receiving port 429a is a through-hole provided so as to penetrate the surface of the cartridge holder 429 facing the back of each cartridge 430. Each receiving port 429a opens toward a first direction X, which is approximately the direction in which each developing unit 9 is aligned. The direction in which each receiving port 429a opens intersects with the direction in which each discharge port 80a opens.

[0050] As shown in Figure 5, on the rear side of the portion of the cartridge holder 429 where each receiving port 429a is provided, the upstream ends 444Yu, 444Mu, 444Cu, and 444Ku (hereinafter referred to as each upstream end 444u) of each supply pipe 444 are connected to the cartridge holder 429 so as to communicate with each receiving port 429a in Figure 4.

[0051] The toner, accompanied by air, received from each inlet 429a is moved through the inside of each supply pipe 444 from each upstream end 444u to each downstream end 444Yd, 444Md, 444Cd, 444Kd (hereinafter referred to as each downstream end 444d) and supplied to each developing unit 9.

[0052] Each downstream end 444d of each replenishment pipe 444 is connected to the end of each developing unit 9 in the second direction Y. Specifically, the downstream end 444Yd of replenishment pipe 444Y and the downstream end 444Md of replenishment pipe 444M are connected to the LE-side end of developing unit Y and the LE-side end of developing unit M, respectively. The downstream end 444Cd of replenishment pipe 444C and the downstream end 444Kd of replenishment pipe 444K are connected to the RE-side end of developing unit C and the RE-side end of developing unit K, respectively.

[0053] This is because, from a general fluid dynamics perspective, the length of the pipe is proportional to the pressure loss, and therefore, shortening the length of each supply pipe 444 reduces the pressure loss. This makes it possible to select smaller pump units 80, and thus miniaturize the image forming unit 500. Of course, depending on the configuration, all four supply pipes 444 may be located on the LE side or the RE side, or they may be divided into three and one.

[0054] Next, the arrangement of cartridge 430Y will be described. As shown in Figure 6(b), cartridge 430Y and each process unit P (each developing unit 9) are arranged on a virtual line VL1 extending in the first direction X. In other words, cartridge 430Y is arranged to be aligned with each developing unit 9 in the first direction X. To put it another way, when viewed in the first direction X, at least a portion of cartridge 430Y is arranged to overlap with each developing unit 9. Cartridges 430M, 430C, and 430K are also arranged to be aligned with each developing unit 9 in the first direction X. To put it another way, when viewed in the first direction X, at least a portion of each of cartridges 430M, 430C, and 430K is arranged to overlap with each developing unit 9. This arrangement of each cartridge 430 makes it possible to reduce the height of the image forming apparatus 1 in the third direction Z, thereby enabling miniaturization of the image forming apparatus 1. Furthermore, each cartridge 430 may have a portion that is located above each process unit (each developing unit 9) in the third direction Z.

[0055] (Cover for supply pipe) Next, the arrangement of each supply pipe 444 and scanner cover 800, which is a characteristic of this embodiment, will be explained using Figures 1 and 7.

[0056] Figure 1 is a cross-sectional view parallel to the plane formed by the optical path LK of the laser beam deflected and scanned from the laser scanner unit LB, which is also shown in Figure 7. Figure 7 is a cross-sectional view of the image forming unit 500 when the laser scanner unit LB is emitting light, and is viewed from direction Y.

[0057] As shown in Figures 1 and 7, the scanner cover 800 is a cover that covers the outside of the laser scanner unit LB. The scanner cover 800 is formed to cover each optical path L that latently images each photosensitive drum 4.

[0058] Specifically, scanner optical path cover Y covering the optical path LY through which the photosensitive drum Y is latent, scanner optical path cover 801M covering the optical path LM through which the photosensitive drum M is latent, scanner optical path cover 801C covering the optical path LC through which the photosensitive drum C is latent, and scanner optical path cover 801K covering the optical path LK through which the photosensitive drum K is latent are arranged on scanner cover 800 (hereinafter referred to as each scanner optical path cover 801).

[0059] As shown in Figure 1, the laser beam is deflected and scanned by mirrors and lenses (not shown) located inside the laser scanner unit LB. As a result, the range over which the laser beam is deflected and scanned widens as it moves away from the laser scanner unit LB. The laser beam that reaches the photosensitive drum 4K creates a latent image on the surface of the photosensitive drum 4K.

[0060] Therefore, the scanner optical path cover 801K also has a guide shape that flares out along the optical path LK. That is, with respect to direction Y, the guide shape 801Ka (first wall portion) of the scanner optical path cover 801K is formed at a predetermined distance D3KL from the optical path LK at one end. Also, on the other end opposite to the one end, the guide shape 801Kb (second wall portion) is formed at a predetermined distance D3KR from the optical path LK.

[0061] Each replenishment pipe 444 is positioned further outward within the device body than the scanner optical path cover 801K. Specifically, replenishment pipes 444Y and 444M are positioned towards the LE side of the scanner optical path cover 801K, while replenishment pipes 444C and 444K are positioned towards the RE side of the scanner optical path cover 801K.

[0062] In other words, the guide shapes 801Ka and 801Kb, which are part of the scanner cover 800 and act as walls, are formed in the region between each replenishment pipe 444 and the optical path LK, and restrict the movement of each replenishment pipe 444.

[0063] In this embodiment, only the scanner optical path cover 801K of the station corresponding to the black toner color has been described, but the same applies to scanner optical path covers 801Y, 801M, and 801C (not shown) corresponding to other toner colors.

[0064] Here, the shape of the scanner optical path cover 801Y is designated as guide shape 801Ya if it is the same as guide shape 801Ka, and the shape of the scanner optical path cover 801Kb is designated as guide shape 801Yb. Similarly, the shape of the scanner optical path cover 801M is designated as guide shape 801Ma if it is the same as guide shape 801Ka, and the shape of the scanner optical path cover 801Kb is designated as guide shape 801Mb. Furthermore, the shape of the scanner optical path cover 801C is designated as guide shape 801Ca if it is the same as guide shape 801Ka, and the shape of the scanner optical path cover 801Kb is designated as guide shape 801Cb.

[0065] Guide shapes 801Ka, 801Ca, 801Ma, and 801Ya are collectively referred to as guide shape 801a. Guide shapes 801Kb, 801Cb, 801Mb, and 801Yb are collectively referred to as guide shape 801b.

[0066] Furthermore, as shown in Figure 7, each scanner optical path cover 801 has guide sections 801Yc, 801Mc, 801Cc, and 801Kc (hereinafter referred to as each guide section 801c, also called the third wall section) formed on one side of each optical path L in the Y direction, separated by their respective gaps (D1Y, D1M, D1C, D1K). In addition, guide sections 801Yd, 801Md, 801Cd, and 801Kd (hereinafter referred to as each guide section 801d, also called the fourth wall section) are formed on the opposite side of each optical path L from the side where 801c is provided, separated by their respective gaps (D2Y, D2M, D2C, D2K).

[0067] Furthermore, the positions of guide shapes 801Ka (first wall) and 801Kb (second wall) in Figure 1 correspond to the portion connecting 801Kc (third wall) and 801Kd (fourth wall) in Figure 7. The portion including the area between 801Kc (third wall) and 801Kd (fourth wall) is the guide shape 801Ka (first wall) and 801Kb (second wall). The same applies to stations of colors other than black (K). Thus, the positions of guide shapes 801Ka (first wall) and 801Kb (second wall) are positioned to overlap with the optical path.

[0068] Therefore, the guide sections 801a, 801b, 801c, and 801d of each scanner optical path cover 801, which are parts of the same laser scanner unit LB, form a guide shape connected to each optical path L. As mentioned above, each optical path L is emitted from the laser scanner unit LB, so assembly errors are reduced because the emitting part and the guiding part are made of the same unit. This makes it possible to configure the optical path so that it is not obstructed even if the distance between each optical path L and each guide section is brought closer by the amount that reduces the error, compared to when they are formed by separate units.

[0069] The laser scanner unit LB consists of a laser light source that emits laser light internally, a polygon mirror that reflects and deflects the laser light emitted from the laser light source, and an optical box that houses these components. The optical box also houses a group of lenses for imaging the deflected laser light onto the surfaces of the photosensitive drums 4Y, 4M, 4C, and 4K. The optical box is a housing that holds these components together and is formed by injection molding. The scanner optical path cover 801 is integrally formed with the optical box. The scanner optical path cover 801 may be configured as a component that is injection molded integrally with the optical box. Alternatively, the scanner optical path cover 801 may be a separate component that is later attached to the optical box by methods such as adhesive or screws to create an integrated connection.

[0070] Here, each process unit P may be configured to perform contact / separation operations with each photosensitive drum 4 from the perspective of the lifespan of each developing roller 6. This is explained in Figure 8. Figure 8(a) shows the developed roller 6 and the photosensitive drum 4 separated (separated position), and Figure 8(b) shows the developed roller 6 and the photosensitive drum 4 in contact (contact position).

[0071] The developing unit 9 can be repeatedly operated by a driving force (not shown) to assume the positions and orientations shown in Figures 8(a) and 8(b). Specifically, rotating the developing unit 9 in the R1 direction around the rotation center 810 (second rotation axis) from the state shown in Figure 8(a) will result in the state shown in Figure 8(b), and rotating it in the R2 direction around the rotation center 810 from the state shown in Figure 8(b) will result in the state shown in Figure 8(a).

[0072] When each developing unit 9 moves in contact with / away from each other, the parts of each developing unit 9 that are connected to each supply pipe 444 also move in accordance with the contact with / away from each other movement, since each lid 811 of each developing unit 9 is connected to each supply pipe 444.

[0073] Specifically, when each lid 811 transitions from the state shown in Figure 8(a) to the state shown in Figure 8(b) (from separated state to contact state), the lid 811 moves in the opposite direction to the direction of arrow X in the figure. Also, when transitioning from the state shown in Figure 8(b) to the state shown in Figure 8(a) (from contact state to separated state), the lid 811 moves in the direction of arrow X in the figure.

[0074] Furthermore, by using a flexible material rather than a rigid one for each supply pipe 444, each supply pipe 444 can follow the movement of each lid 811 as it moves.

[0075] The operation of each supply pipe 444 will be explained in detail using Figure 9. Figure 9(a) is a top view of the image forming unit 500 with each developing roller 6 separated from each photosensitive drum 4, and Figure 9(b) is a top view of the image forming unit 500 with each developing roller 6 in contact with each photosensitive drum 4.

[0076] As shown in Figure 9(a), when each developing roller 6 (not shown) and each photosensitive drum 4 (not shown) are separated, each flexible replenishment pipe 444 is bent and arranged in an arc. It can be said that each replenishment pipe 444 is configured to bend. When the state changes from this to the state in which each developing roller 6 and each photosensitive drum 4 come into contact, as shown in Figure 9(b), each lid 811 moves in the opposite direction to the arrow X in the figure, as described above, causing each replenishment pipe 444 to be stretched and pulled. Each upstream end 444u of the replenishment pipe 444 is fixed so as to be able to communicate with each receiving port 429a of the cartridge holder 429. Therefore, when each lid 811 moves in the opposite direction to the arrow X in the figure, each replenishment pipe 444 moves inward into the image forming unit 500 (see Figure 5). That is, the central parts of replenishment pipes 444Y and 444M move in the Y direction, and the central parts of replenishment pipes 444C and 444K move in the opposite direction to the Y direction. In other words, it approaches each optical path L. Naturally, in the contact state, the laser scanner unit LB emits light and each optical path L is formed, and a latent image is formed on each photosensitive drum 4 during the image formation process, so it is necessary to avoid the supply pipe 444 coming into contact with each optical path L. Therefore, the supply pipe 444 is positioned in a way that corresponds to the deformation of the supply pipe 444 during the contact and separation operation of development.

[0077] Figure 10(a) shows a cross-sectional view parallel to the optical path LC when the laser beam is scanned while each developing roller 6 and each photosensitive drum 4 are separated, and Figure 10(b) shows a cross-sectional view parallel to the optical path LC when each developing roller 6 and each photosensitive drum 4 are in contact.

[0078] As shown in Figures 10(a) and (b), the guide sections 801Ca and 801Cb of the scanner optical path cover 801C protect the optical path LC from each supply pipe 444, and furthermore, the supply pipes 444 can be positioned closer to the optical path LC, contributing to the miniaturization of the main unit. Although Figures 10(a) and (b) describe the optical path LC, the same applies to the other optical paths LY, LM, and LK.

[0079] Furthermore, from the perspective of the lifespan of each developing roller 6 and photosensitive drum 4, the image forming unit 500 may be configured to be retractable from the main body 72 of the apparatus. The configuration in that case will be explained using Figures 11 and 12.

[0080] Figure 11(a) is a cross-sectional view of the process unit PK in the withdrawal direction H (shown in Figure 12) of the image forming unit 501. Figures 11(b) and (c) are perspective views showing only each process unit P, each supply pipe 444, and the scanner cover 800. Figure 12 is a perspective view of the image forming unit 501 configured to be retractable.

[0081] As shown in Figure 11(a), the lid 821K and scanner optical path cover 820KL of the developing unit 9K of the process unit P are formed at a distance of D5, and similarly the lid 821K and scanner optical path cover 820KR are formed at a distance of a predetermined gap D6, thereby enabling the image forming unit 501 to be pulled out.

[0082] Furthermore, in the pulling direction H, the same applies to the lids 821Y, 821M, and 821C of the developing units 9Y, 9M, and 9C, and their respective scanner optical path covers 820YL, 820ML, and 820CL. The shape is formed at a predetermined gap D5 away from the black toner station as described above. Also, the lids 821Y, 821M, and 821C and their respective scanner optical path covers 820YR, 820MR, and 820CR are separated by a predetermined gap D6, as described above.

[0083] In this configuration, the connection points between each supply pipe 444 and each cover 821 are formed on the outside of each scanner optical path cover 820, as shown in Figures 11 and 12. Specifically, supply pipes 444Y and 444M are located on the LE side of the scanner optical path cover 820L, and supply pipes 444C and 444K are located on the RE side of the scanner optical path cover 820R.

[0084] As a result, in a configuration in which toner discharged from each cartridge 430 along with air is sent to the process unit P, it is possible to contribute to miniaturization of the main unit. Specifically, by using the scanner optical path covers 801, 820L, and 820R, the flexible supply pipes 444 can be protected from each optical path L. Furthermore, it becomes possible to bring each supply pipe 444 as close as possible to the optical path L.

[0085] <Second Embodiment> A second embodiment of the present invention will now be described. In this embodiment, the image forming apparatus, image forming operation, removable cartridge, and toner transport are the same as in the first embodiment and will therefore be omitted. This will be explained with reference to Figures 13 and 14.

[0086] Figure 13 is a cross-sectional view (projection plane) of the process unit PK in the withdrawal direction H2 (shown in Figure 14) of the image forming unit 502. Figure 14 is a perspective view of the image forming unit 502 of the second embodiment.

[0087] As in the first embodiment, forming a guide shape on the scanner cover 800 to protect each supply pipe 444 from each optical path L can also contribute to miniaturizing the main unit. When extending the image forming unit 501, it is preferable to avoid the scanner optical path cover and make the toner container shape smaller to limit the toner capacity.

[0088] However, toner capacity is also an important factor in meeting user needs. When comparing toner capacity with the ability to miniaturize the main unit, there is a need for a form that prioritizes ensuring a sufficiently large toner capacity while miniaturizing the unit as much as possible within that range. This embodiment describes a configuration that meets such needs.

[0089] As shown in Figure 13, a guide shape 831KL is formed on the LE side of the lid 831K of the process unit PK (fourth developing unit). Since the guide shape 831KL is formed at a predetermined distance J1K away from the optical path LK on the LE side, it is possible to protect the optical path LK from the supply pipes 444Y and 444M. Similarly, the guide shape 831KR is formed at a predetermined distance J2K away from the optical path LK on the RE side. With this configuration, it is possible to protect the optical path LK from the supply pipes 444C and 444K.

[0090] In other words, in the cross-sectional view (projection plane) of the image forming unit 502 in the withdrawal direction, a guide shape 831KL is formed between the supply pipe 444K and the optical path LK in a part of the process unit PK side.

[0091] Although Figure 13 uses process unit PK (fourth developing unit) for explanation, the same applies to stations other than the black color shown in Figure 14. In other words, the same applies to process unit PY (first developing unit), process unit PM (second developing unit), and process unit PC (third developing unit).

[0092] Specifically, on the LE-side sides of covers 831Y, 831M, and 831C, guide shapes 831YL, 831ML, and 831CL are formed at predetermined distances J1Y, J1M, and J1C (not shown) from the optical paths LY, LM, and LC, respectively. In addition, on the RE-side sides of covers 831Y, 831M, and 831C, guide shapes 831YR, 831MR, and 831CR are formed at predetermined distances J2Y, J2M, and J2C (not shown) from the optical paths LY, LM, and LC, respectively.

[0093] This ensures toner capacity as in the first embodiment, while protecting each optical path L from each supply pipe 444, and also allows the image forming unit 501 to be pulled out along with the guide shape. Since the guide shape 831YR etc. moves with the pulling operation, there is no friction with the supply pipe 444 during the pulling operation. [Explanation of Symbols]

[0094] 1. Image forming apparatus 3. Developing container 4 Photosensitive drum 6. Developing roller 9. Developing Unit 72 Main unit of the device 80 Pump Unit 83 filters 83a Flange section 83b bottom 85 Discharge pipe 429 Cartridge holder 430 cartridges 430a First Frame 430b 2nd frame 430a1 outlet 430b Inlet 444 Supply Pipe 500 Image Forming Units 800 Scanner Cover 801 Scanner optical path cover 810 Rotation Center 820 Scanner Optical Path Cover 811 Lid 821 Lid P Process Unit LB Laser Scanner Unit X First direction Y Second direction Z Third direction H Pull-out direction H2 Drawer direction

Claims

1. Laser scanner and A first photosensitive drum in which an electrostatic latent image is formed on the surface when a laser beam is irradiated by the laser scanner, the first photosensitive drum being configured to be rotatable, A second photosensitive drum on which an electrostatic latent image is formed on its surface when irradiated with laser light by the laser scanner, comprising a second photosensitive drum aligned with the first photosensitive drum in a first direction intersecting the direction of gravity, A first developing unit having a first developing roller that supplies first toner to the first photosensitive drum and develops a first toner image, and a first developing container that contains the first toner to be carried on the first developing roller, A second developing unit having a second developing roller that supplies a second toner to the second photosensitive drum and develops a second toner image, and a second developing container that contains the second toner to be carried on the second developing roller, A first toner container for containing the first toner to be replenished in the first developing container, A second toner container for containing the second toner to be replenished in the second developing container, the second toner container being aligned with the first toner container in a second direction intersecting the direction of gravity and the first direction, A first pipe through which the first toner supplied from the first toner container to the first developing container passes, the first pipe being bendable and flexible A second pipe through which the second toner supplied from the second toner container to the second developing container passes, the second pipe being bendable and flexible, A wall to restrict the position of the aforementioned pipe, Equipped with, The second photosensitive drum is positioned between the first toner container and the first developing container in the first direction. A portion of the first pipe is provided so as to pass through an area outside the optical path of the laser light irradiated from the laser scanner to the second photosensitive drum in the second direction. At least a portion of the wall is provided in the region between the portion of the first pipe and the optical path in the second direction, and in the region that overlaps with the optical path when viewed in the direction of the rotation axis of the second photosensitive drum. An image forming apparatus characterized by the following features.

2. When the wall is referred to as the first wall portion, the first wall portion is a part of the laser scanner and is a plate configured such that it moves further away from the laser scanner as it moves away from the center of the second photosensitive drum in the second direction. The image forming apparatus according to feature 1.

3. When the wall is referred to as the first wall portion, the first wall portion is a part of the second developing unit and is a plate configured such that it moves closer to the center of the second photosensitive drum in the second direction as it moves away from the second developing unit. The image forming apparatus according to feature 1.

4. A second toner container containing the second toner that is transported to the second developing container, An image forming unit configured to integrally hold the first developing unit, the second developing unit, the first toner container, and the second toner container, Equipped with, The image forming unit is configured to be retractable from the main body of the image forming apparatus. The image forming apparatus according to feature 3.

5. A third photosensitive drum having a rotation axis along the second direction, the third photosensitive drum being aligned with the first photosensitive drum along the first direction and positioned between the first photosensitive drum and the second photosensitive drum in the first direction, A third developing unit comprising: a third developing roller for supplying a third toner to the third photosensitive drum and developing a third toner image, the third developing roller having a rotation axis along a second direction which is the direction of the rotation axis; and a third developing container for housing the third developing roller; A third toner container containing a third toner, which is aligned with the first toner container in the second direction, A third pipe connected to the third toner container and the third developer container, through which the third toner is transported from the third toner container to the third developer container along with air, the third pipe being configured to bend in the second direction, When the aforementioned wall is defined as a first wall portion, the second wall portion is provided in the second direction on the side opposite to the side on which the first wall portion is provided with respect to the optical path, and is located at a position overlapping with the optical path in the first direction, and further comprises a second wall portion provided outside the optical path in the second direction. The image forming apparatus according to feature 1.

6. The aforementioned laser scanner A laser light source that emits the aforementioned laser light, A polygon mirror that reflects, deflects, and scans the laser light emitted from the aforementioned laser light source, A lens that images the laser light scanned by the polygon mirror onto the second photosensitive drum, An optical box that houses and holds the laser light source, the polygon mirror, and the lens, It has, When the wall is referred to as the first wall portion, the first wall portion is integrally connected to the optical box. The image forming apparatus according to feature 1.

7. When viewed in the second direction, A third wall portion is a plate provided on one side of the optical path and extending along the optical path, and a fourth wall portion is a plate provided on the other side of the optical path and extending along the optical path. Furthermore, When the aforementioned wall is designated as the first wall portion, the third wall portion and the fourth wall portion are connected by the first wall portion. The image forming apparatus according to feature 1.

8. The first developing roller is configured to be movable between a contact position in contact with the first photosensitive drum and a separation position separated from the first photosensitive drum, and in a cross-section along the optical path of the laser light after it has been emitted from the laser scanner, the distance between the first pipe and the optical path is shorter at the contact position than at the separation position. The image forming apparatus according to feature 1.

9. When the rotation axis of the first photosensitive drum is defined as the first rotation axis, With respect to the first drum unit having the first photosensitive drum, the first developing unit having the first developing roller is configured to move between a contact position where the first developing roller is in contact with the first photosensitive drum and a separated position where the first developing roller is separated from the first photosensitive drum by rotating around a second rotation axis parallel to the first rotation axis. When viewed in the second direction, the first pipe is located above the second rotation axis in the direction of gravity, and the first photosensitive drum is located below the second rotation axis. The image forming apparatus according to feature 1.

Images