Image forming apparatus and cartridge

Abstract

The present invention relates to a cartridge comprising: a second transfer roller forming a nip with a first transfer roller; a storage part for storing foreign matters; and a contact member that contacts the second transfer roller to restrict leakage of foreign matter. The device body includes a biasing member that biases the second transfer roller toward the first transfer roller. The second transfer roller is in a first position where a nip is formed with the first transfer roller by a biasing force of the biasing member when the cartridge is attached to the apparatus main body, and is in a second position when the cartridge is detached from the apparatus main body. The contact member is in contact with the second transfer roller both when the second transfer roller is in the first position and when the second transfer roller is in the second position. The invention also relates to an image forming apparatus for forming an image on a recording material.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, and is particularly suitable for an image forming apparatus that records a developer image on a recording material such as paper, or a cartridge that can be attached to and detached from such an image forming apparatus. Background Art

[0002] In image forming apparatuses, a so-called electrophotographic method is widely used in which a developer is recorded on a recording material such as paper. A configuration has been proposed in which, when an image is formed on a recording material such as paper, foreign matter such as dust generated from the recording material (generally, paper powder (filler, pulp, originally attached foreign matter, etc.) generated from recording paper used as a recording material) is removed from the recording paper (for example, Japanese Patent Laid-Open Nos. 2001-075457 and 2020-201316). Summary of the invention

[0003] An object of the present invention is to provide a better apparatus configuration in an image forming apparatus including a foreign matter removing unit.

[0004] In order to solve the above problems, an image forming device for forming an image on a recording material according to the present invention comprises:

[0005] an apparatus main body having a first conveying roller; and

[0006] a cassette having a second conveying roller which forms a nip portion for conveying a recording material with the first conveying roller, the cassette being configured to be attachable to and detachable from the apparatus main body,

[0007] wherein the box comprises:

[0008] a holding portion configured to movably hold the second conveying roller in an opposing direction in which the first conveying roller and the second conveying roller forming the nip portion are opposed to each other;

[0009] a removing member configured to remove foreign matter from the second conveying roller by contacting the second conveying roller;

[0010] a storage portion configured to store foreign matter removed by the removing member; and

[0011] a contact member configured to contact the second conveying roller at a position different from that of the removing member so as to restrict leakage of foreign matter from the storage portion,

[0012] wherein the apparatus body has a biasing member configured to bias the second conveying roller in a direction toward the first conveying roller when the cassette is attached to the apparatus body,

[0013] wherein, when the cartridge is attached to the apparatus main body, the second conveying roller is in a first position to form the nip portion by contacting the first conveying roller due to the biasing force of the biasing member, and when the cartridge is detached from the apparatus main body, the second conveying roller is in a second position, and

[0014] Wherein the contact member is in contact with the second conveying roller both when the second conveying roller is in the first position and when the second conveying roller is in the second position.

[0015] Furthermore, in order to solve the above-mentioned problem, a cartridge according to the present invention is attachable to and detachable from an apparatus main body of an image forming apparatus having a first conveying roller, the cartridge comprising:

[0016] a second conveying roller configured to form a nip portion for conveying the recording material with the first conveying roller;

[0017] a holding portion configured to movably hold the second conveying roller in an opposing direction in which the first conveying roller and the second conveying roller forming the nip portion are opposed to each other;

[0018] a removing member configured to remove foreign matter from the second conveying roller by contacting the second conveying roller;

[0019] a storage portion configured to store foreign matter removed by the removing member; and

[0020] a contact member configured to contact the second conveying roller at a position different from that of the removing member so as to restrict leakage of foreign matter from the storage portion,

[0021] wherein when the cartridge is attached to the apparatus main body, the second conveying roller is in a first position to form the nip portion by contacting the first conveying roller, and when the cartridge is detached from the apparatus main body, the second conveying roller is in a second position, and

[0022] Wherein the contact member is in contact with the second conveying roller both when the second conveying roller is in the first position and when the second conveying roller is in the second position.

[0023] According to the present invention, the configuration of an image forming apparatus including a foreign matter removing unit can be improved.

[0024] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of an image forming apparatus;

[0026] Figure 2 is a perspective view of the main body of the device;

[0027] Figure 3 is a perspective view of the drum cartridge and the developer cartridge;

[0028] Figure 4A and 4B is a schematic diagram showing how the drum cartridge is attached to and detached from the apparatus main body;

[0029] Figure 5 is a perspective view of the drum cartridge and the developer cartridge in a separated state;

[0030] Fig. 6A and 6B is a schematic diagram showing the combination and separation of a drum cartridge and a developer cartridge;

[0031] Fig. 7A and 7B is a partially enlarged perspective view showing the left end of the second conveying roller and its surrounding area;

[0032] Figures 8A to 8D is a partially enlarged schematic diagram showing the moving path of the first conveying roller bearing;

[0033] Fig. 9 is a partial cross-sectional view of a transfer roller, a drum cartridge, and a developer cartridge;

[0034] Fig. 10A and 10B is a partial cross-sectional view showing the positional relationship between the conveying paper dust recovery portion and the second conveying roller;

[0035] Fig.11A and 11B is a partial cross-sectional view showing the positional relationship between the conveying paper dust recovery portion and the second conveying roller;

[0036] Fig.12 is a partial cross-sectional view showing a schematic configuration of a drum cartridge and a developing cartridge;

[0037] Fig.13 is a partial cross-sectional view showing a schematic configuration of a conveying paper powder recovery portion and a developing cartridge;

[0038] Fig.14is a partial cross-sectional view showing a schematic configuration of a conveying paper powder recovery portion and a developing cartridge;

[0039] Fig.15 is a partial cross-sectional view showing a schematic configuration of a conveying paper powder recovery portion and a developing cartridge; and

[0040] Fig.16A and 16B is a partial cross-sectional view showing a schematic configuration of another box mode. DETAILED DESCRIPTION

[0041] Example 1

[0042] Hereinafter, embodiments of the present invention will be described in detail based on embodiments and examples with reference to the accompanying drawings. However, the size, material, shape, relative arrangement, etc. of the constituent parts described in this embodiment will be appropriately modified according to the configuration and various conditions of the device to which the present invention is applied. That is, the scope of the present invention should not be limited to the following embodiments.

[0043] Will refer to Figure 1 A schematic configuration of an image forming apparatus using electrophotography according to an embodiment of the present invention is described. Figure 1 : is a schematic cross-sectional view showing a schematic configuration of an image forming apparatus. Note that, Figure 1 A state in which the image forming apparatus is installed on a horizontal surface is shown as a normally assumed installation state of the image forming apparatus, and Figure 1 , each direction on the page is defined as follows. The up-down direction of the page is the vertical direction (gravity direction), the upward direction of the page is called the upward direction, and the downward direction of the page is called the downward direction. The leftward direction of the page is called the backward direction, and the rightward direction of the page is called the forward direction. In addition, the forward direction on the page (the direction perpendicular to the paper surface and extending from the far side of the page to the near side of the page) is the leftward direction, and the backward direction (the direction perpendicular to the page and extending from the near side of the page to the far side of the page) is called the rightward direction.

[0044] Here, it is assumed that the image forming apparatus to which the present invention is applied is typically an image forming apparatus using an electrophotographic recording method, such as a laser printer, a copier, or a facsimile machine.

[0045] Electrophotographic image forming device

[0046] like Figure 1 As shown, the image forming section 4 is arranged at the center of the apparatus body 1 of the image forming apparatus. Furthermore, the paper feeding section 2 is arranged below the image forming section 4, and the conveying section 3 is arranged in front of the paper feeding section 2. Furthermore, the fixing section 5 is arranged behind the image forming section 4. The paper discharge section 6 is arranged behind the fixing section 5. Furthermore, the stacking section 7 is arranged above the image forming section 4.

[0047] The paper feeding section 2 conveys the recording material S to the image forming section 4 via the conveying section 3. In the image forming section 4, an image is formed on the conveyed recording material S, and then the recording material S is conveyed to the fixing section 5. The image formed on the recording material S is fixed to the recording material S by the fixing section 5. The recording material S on which the image is fixed is discharged from the paper discharging section 6 to the outside of the apparatus body, and is stacked in the stacking section 7.

[0048] Paper feeding section and conveying section

[0049] The paper feeding portion 2 is constituted by a cassette portion 20 in which recording materials S are stacked and stored, and a pickup portion 21 that conveys the stacked and stored recording materials S one by one to the image forming portion 4 .

[0050] The conveying section 3 is composed of an upstream conveying roller pair 30 that conveys the recording material S to the image forming section 4, a conveying guide 31 that restricts the moving path of the recording material S, and a downstream conveying roller section 32 that conveys the recording material S to the image forming section 4. The downstream conveying roller section 32 is located upstream of the image forming section 4 on the conveying path of the recording material S, and is composed of a first conveying roller 321 and a second conveying roller 322. The first conveying roller 321 is rotatably supported by the apparatus body 1, and is rotated by being driven by a drive transmission unit (not shown). During the image forming operation, the first conveying roller 321 contacts the back surface of the recording material S on the side opposite to the image forming surface. The second conveying roller 322 is rotatably supported by the drum cartridge 41 and contacts the image forming surface of the recording material S during the image forming operation.

[0051] The pickup portion 21 operates according to the image forming operation, feeds the recording materials S in the cassette portion 20 one by one, and conveys the recording materials S to the conveying portion 3 .

[0052] The upstream conveying roller pair 30 is driven by a driving force transmitted by a driving device (not shown). The recording material S is clamped by the upstream conveying roller pair 30 and conveyed along the conveying guide 31. The first conveying roller 321 is composed of a metal shaft and a rubber roller. During the image forming operation, the first conveying roller 321 of the downstream conveying roller portion 32 is driven by a driving transmission unit (not shown), and conveys the recording material S to the image forming portion 4.

[0053] Furthermore, during the image forming operation, the first transport roller 321 of the downstream transport roller portion 32 can perform, in a predetermined order, an operation of keeping the recording material S still and waiting, and an operation of transporting the recording material S to the image forming portion 4. By this operation, the positions of the developer image and the recording material S are aligned in the image forming step as the next step.

[0054] Due to the friction force of the rubber roller portion of the first transport roller 321, the recording material S is reliably transported to the image forming portion 4. In this embodiment, the second transport roller 322 is configured to be rotated by the first transport roller 321. However, the second transport roller 322 may also be configured to be rotationally driven by a drive transmission device (not shown).

[0055] Image forming part

[0056] The image forming portion 4 includes a laser scanner unit 40 (ie, a latent image forming unit), a drum cartridge 41 , and a developing cartridge 42 .

[0057] The drum cartridge 41 is composed of a photosensitive drum 411, a charging portion 412, a transfer roller 413, a cleaning portion 414, and a recovery portion 415. The photosensitive drum 411 is an image bearing member that bears a developer image. The charging portion 412 is a charging unit that performs a charging process on the photosensitive drum 411. The cleaning portion 414 is a cleaning member for cleaning paper dust and the like attached to the photosensitive drum 411. The recovery portion 415 is a recovery unit for recovering paper dust and the like cleaned by the cleaning member.

[0058] The developing box 42 includes a developing roller 421, a developing blade 422, a supply roller 423, a conveying paddle 424, and a developer storage portion 425. The developing roller 421 is a developer carrying member that carries the developer. The developing blade 422 is a developer regulating member that controls the layer thickness of the developer carried by the developing roller 421. The supply roller 423 is a developer supply member that supplies the developer to the developing roller 421. The conveying paddle 424 is a developer conveying portion (conveying member) for conveying the developer to the supply roller 423. The developer storage portion 425 is a developer storage unit for storing the developer.

[0059] The laser scanner unit 40 irradiates the photosensitive drum 411 with the latent image light L obtained by processing the image information by the processing unit (not shown). A predetermined bias is applied to the charging portion 412 by a bias applying unit (not shown), and the surface of the photosensitive drum 411 is charged. An electrostatic latent image is formed on the surface of the photosensitive drum 411 by the latent image light L. The developer stored in the developer storage portion 425 is conveyed to the supply roller 423 by the conveying paddle 424. The conveyed developer is supplied to the developing roller 421 by the supply roller 423. The layer thickness of the developer supplied to the developing roller 421 is regulated by the developing blade 422, and the charge is applied by friction charging. A predetermined bias is applied to the developing roller 421 by a bias applying unit (not shown). The developer carried on the developing roller 421 is developed on the electrostatic latent image by the applied bias and the potential difference of the electrostatic latent image formed on the photosensitive drum 411. In this way, the developer image is carried on the photosensitive drum 411. Here, the recording material S conveyed by the conveying portion 3 is conveyed to the nip portion between the photosensitive drum 411 and the transfer roller 413. A predetermined bias is applied to the transfer roller 413 by a bias applying unit (not shown). The developer image carried on the photosensitive drum 411 is transferred to the recording material S by the potential difference of the bias applied to the transfer roller 413.

[0060] Foreign matter (eg, paper dust) that has moved from the recording material S to the photosensitive drum 411 is scraped off the surface of the photosensitive drum 411 by the cleaning portion 414 and recovered by the recovery portion 415 .

[0061] Fixing part

[0062] The fixing part 5 includes a fixing frame 50, a heating roller 51, and a pressure roller 52. The fixing frame 50 rotatably supports the heating roller 51 and the pressure roller 52. The heating roller 51 includes a heating unit (not shown), and the heating roller 51 is heated thereby. The pressure roller 52 is pressed toward the heating roller 51 by the pressure unit (not shown). In addition, the heating roller 51 and the pressure roller 52 are driven by a driving unit (not shown). The recording material S, on the surface of which the developer image has been formed and which is conveyed from the image forming part 4, is clamped by the clamping portion between the heating roller 51 and the pressure roller 52. Here, the developer image is fixed to the recording material S by heating and pressurizing.

[0063] Paper discharge section, stacking section

[0064] The paper discharge section 6 is composed of a paper discharge conveying roller pair 60, a paper discharge conveying guide 61, and a paper discharge roller pair 62. The stacking section 7 includes a paper discharge outlet 70 and a paper discharge tray 71. The paper discharge conveying roller pair 60 and the paper discharge roller pair 62 are driven by a driving unit (not shown). The recording material S on which the developer image has been fixed by the fixing section 5 passes through the paper discharge conveying roller pair 60 through the paper discharge conveying guide 61, is discharged from the paper discharge outlet 70 by the paper discharge roller pair 62, and is stacked in the paper discharge tray 71.

[0065] Example 1

[0066] Will refer to Figure 1 to Figure 1 1 describes an image forming apparatus according to Example 1 as a first aspect of the present invention. However, the scope of the present invention should not be limited only to the shapes of the constituent components, their relative arrangements, and the like described in this example unless otherwise specifically stated.

[0067] Attachment and removal of drum cartridge and developer cartridge

[0068] Will refer to Figure 1 , Figure 2 , Figure 3 , Figure 4A , Figure 4B , Figure 5 , Fig. 6A and Figure 6B Attachment and detachment of the drum cartridge 41 and the developing cartridge 42 in this embodiment are described.

[0069] like Figure 1 As shown, the drum cartridge 41 and the developer cartridge 42 are each formed as a unit. When each unit reaches a predetermined life, these units can be easily replaced. In addition, during image formation, if the recording material S is retained inside the device body 1 (so-called paper jam), the drum cartridge 41 and the developer cartridge 42 are disassembled from the device body, and the retained recording material S is removed.

[0070] Figure 2 1 is a perspective view of the device body 1 in this example. Figure 2 As shown in FIG. 1 , a cartridge door 11 and a cartridge guide 12 are provided on the front side of the apparatus body 1. The cartridge door 11 is supported by the apparatus body 1 in an openable and closable manner. Figure 2 , the cartridge door 11 is shown in an open state. The cartridge guide 12 is a guide portion for restricting a moving path when the drum cartridge 41 is attached to and detached from the device body 1. The cartridge guide 12 has a groove-like shape formed on the inner wall of the device body 1 in a bilaterally symmetrical manner.

[0071] Figure 3 4 is a perspective view of the drum cartridge 41 and the developer cartridge 42 in this embodiment. Figure 3In FIG. 4 , the developing cartridge 42 is shown to be combined with the drum cartridge 41. Figure 3 As shown, the drum cartridge 41 and the developing cartridge 42 as a cartridge unit can be attached to and detached from the apparatus main body 1 in a mutually coupled state. The drum cartridge 41 includes a drum cartridge frame (drum frame) 410, a drum side cover 416, a drum cartridge boss 4161, and a drum cartridge rotation stop boss 4162. The drum cartridge frame 410 is a drum cartridge frame in which the drum cartridge 410 is mounted. Figure 1 The photosensitive drum 411, the charging portion 412, the transfer roller 413, the cleaning portion 414, the recovery portion 415, and the downstream conveying paper powder recovery portion 417 are shown as a frame in which the drum cartridge frame 410 is integrally attached to each other. In addition, the drum side cover 416 is attached to the left and right ends of the drum cartridge frame 410. The drum cartridge boss 4161 and the drum cartridge rotation stop boss 4162 have a cylindrical shape protruding from the side surface of the drum side cover 416. The protruding direction of the drum cartridge boss 4161 and the drum cartridge rotation stop boss 4162 is parallel to the longitudinal direction of the drum cartridge 41 or the rotation axis of the photosensitive drum 411, and is perpendicular to the direction of inserting and removing the drum cartridge 41 into and from the device body 1. When inserting or removing the drum cartridge 41, the drum cartridge boss 4161 and the drum cartridge rotation stop boss 4162 are guided by engaging with the cartridge guide 12.

[0072] Will refer to Figure 4A and Figure 4B A method for attaching and detaching the drum cartridge 41 to and from the apparatus main body 1 is described. Figure 4A and 4B 4 is a schematic cross-sectional view showing how the drum cartridge 41 is attached to and detached from the apparatus main body 1. In addition, Figure 4A There is shown a state in which the drum cartridge 41 is attached to the inside of the apparatus body 1 and the cartridge door 11 is opened. Figure 4B A state in which the drum cartridge 41 is detached from the apparatus main body 1 and the cartridge door 11 is opened is shown.

[0073] The cartridge guide 12 is a guide portion for guiding the drum cartridge 41 to a predetermined position in the apparatus main body 1 when the drum cartridge 41 is attached to the apparatus main body 1. At the same time, the cartridge guide 12 also serves as a positioning portion for positioning the drum cartridge 41 at a predetermined position in the apparatus main body 1 by engaging with the drum cartridge boss 4161. Figure 4AAs shown, the drum cartridge 41 is attached to the inside of the device body 1. At this time, the cartridge guide 12 and the drum cartridge boss 4161 are engaged with each other. In addition, the cartridge guide 12 and the drum cartridge rotation stop boss 4162 are also engaged with each other. That is, when the drum cartridge boss 4161 and the drum cartridge rotation stop boss 4162 formed on the left and right sides of the drum cartridge 41 are engaged with the cartridge guide 12, the drum cartridge 41 is positioned at a predetermined position. It should be noted that the drum cartridge rotation stop boss 4162 may also be arranged only on the left or right side. On the other hand, by providing the drum cartridge rotation stop boss 4162 on both the left and right sides, the stability of the insertion operation of the drum cartridge 41 is improved.

[0074] When the drum cartridge 41 is attached or detached, the cartridge door 11 is opened. Then, when the drum cartridge 41 is attached and image formation is performed, the cartridge door 11 is closed. In this embodiment, the cartridge door 11 is configured to swing open and close in a manner using the swing center as a reference. Other configurations may also be used to open the interior of the device body 1.

[0075] When removing the drum cartridge 41 from the apparatus main body 1, the user grabs the drum cartridge 41 and moves the drum cartridge 41 forward. At this time, the drum cartridge boss 4161 and the drum cartridge rotation stopping boss 4162 move while remaining engaged with the cartridge guide 12. This makes it possible to limit the moving path of the drum cartridge 41 relative to the apparatus main body 1.

[0076] When inserting the drum cartridge 41 into the apparatus body 1, the reverse operation to the removal operation is performed. Figure 4B As shown, the vertical width of the cartridge guide 12 is wider at the front side. The user aligns the drum cartridge boss 4161 with the cartridge guide 12 and inserts the drum cartridge boss 4161. When the attachment is completed, the user closes the cartridge door 11, thereby completing the insertion operation and placing the image forming apparatus in a state where an image forming operation can be performed.

[0077] Will refer to Figure 5 , Fig. 6A and Figure 6B The combination and separation of the drum cartridge 41 and the developing cartridge 42 will be described. Figure 5 1 is a schematic perspective view showing a state in which the drum cartridge 41 and the developing cartridge 42 are separated from each other. Fig. 6A and 6B 1 is a schematic side view showing the combination and separation of the drum cartridge 41 and the developing cartridge 42. Fig. 6A A state in which the drum cartridge 41 and the developing cartridge 42 are separated from each other is shown. Figure 6B A state in which the drum cartridge 41 and the developing cartridge 42 are coupled to each other is shown.

[0078] like Figure 5As shown, the developer cartridge guide 4163 is formed on the inner wall of the drum side cover 416. In addition, the developer cartridge 42 includes a developer cartridge frame (developer frame) 420 and developer side covers 426 attached to the left and right ends of the developer cartridge frame 420. In addition, a developer cartridge guide pin 4261 is formed on the developer side cover 426.

[0079] The developer cartridge guides 4163 are two grooves formed in the drum side cover 416. The developer cartridge guides 4163 are formed on the inner side surfaces of the left and right drum side covers 416 that are opposite to each other along the longitudinal direction of the drum cartridge 41 (the rotation axis of the photosensitive drum 411). Figure 1 As shown, the developing box frame 420 is a frame for integrally attaching a developing roller 421, a developing blade 422, a supply roller 423, a conveying paddle 424 and a developer storage portion 425.

[0080] Will refer to Fig. 6A and Figure 6B The process for combining the developing cartridge 42 with the drum cartridge 41 is described below. Fig. 6A As shown, two (a pair) of developer cartridge guide pins 4261 are aligned with two (a pair) of developer cartridge guides 4163, and the drum cartridge 41 and the developer cartridge 42 move relative to each other. Since the developer cartridge guide pins 4261 are engaged with the developer cartridge guides 4163, the developer cartridge 42 moves along the drum cartridge 41 and the developer cartridge 42. Fig. 6A The dotted line in FIG. 4 moves relative to the drum cartridge 41. Then, as Figure 6B As shown, when the developer box guide pin 4261 reaches the end (deepest part) of the developer box guide 4163, the combination of the drum box 41 and the developer box 42 is completed.

[0081] The developing cartridge 42 can be detached from the apparatus body 1 while maintaining the combined state with the drum cartridge 41, and then separated from the drum cartridge 41 and replaced. The developing cartridge 42 can also be separated while the drum cartridge 41 is attached to the apparatus body 1 and replaced.

[0082] Moving path of the second transport roller when attaching and detaching the drum cartridge

[0083] Will refer to Figure 2 and 7A to 8D The moving path of the second transport roller 322 when the drum cartridge 41 is attached and detached is described.

[0084] like Figure 2 As shown, the second conveying roller guide 13 and the second conveying roller pressing spring 14 are arranged inside the apparatus body 1. The second conveying roller guide 13 restricts the moving path of the second conveying roller 322 when it moves inside the apparatus body 1. When the drum cartridge 41 is attached to the apparatus body 1, the second conveying roller pressing spring 14 serving as a biasing member presses the second conveying roller 322 toward the first conveying roller 321. Figure 2There are shown the second conveying roller guide 13 and the second conveying roller pressing spring 14 arranged on the right inner wall of the apparatus body 1. Similarly, the second conveying roller guide 13 and the second conveying roller pressing spring 14 are also arranged on the left inner wall.

[0085] Fig. 7A and 7B 3 is a partially enlarged perspective view showing the left end portion of the second conveying roller 322 and its surrounding area. Fig. 7A The left end portion of the second conveying roller 322 is shown in a state where the driven roller bearing 3221 is rotatably supported. Figure 7B 4 shows a state when the drum cartridge 41 is attached to the apparatus body 1 and the second conveying roller 322 is installed in the apparatus body 1. When the drum cartridge boss 4161 reaches the end (deepest part) of the cartridge guide 12, Figure 7B The states shown correspond to Figure 4A Note that, although not shown in the figure, the right end portion of the second transport roller 322 and its surrounding area are constructed in a similar manner.

[0086] like Fig. 7A As shown, a locking hook portion 3222 serving as a locking portion is formed in the driven roller bearing 3221, and forms a holding portion for holding the second conveying roller 322 together with a locking hook receiving hole 4101 of the drum cartridge frame 410 serving as a locked portion. By this holding portion, the second conveying roller 322 is held to be movable relative to the drum cartridge frame 410 in a direction opposite to the first conveying roller 321. In a state where no external force is applied to the second conveying roller 322, the second conveying roller 322 is held in a second position where the locking hook portion 3222 and the locking hook receiving hole 4101 are locked to each other by its own weight. The driven roller bearing 3221 rotatably supports the second conveying roller 322, so a material having high sliding property can be selected. The locking hook portion 3222 can be selected from an elastic material so that they can be bent during the assembly task. Examples of materials having high sliding property and having elasticity include polyacetal, polycarbonate, etc. In addition, if it is necessary to apply a bias to the second conveying roller 322, a material having conductivity, sliding property, and elasticity is selected. As such a material, conductive polyacetal or the like can be selected.

[0087] That is, it can be said that the holding portion of the present invention includes a bearing provided at the end of the second conveying roller, a locking portion provided on the bearing, and a locked portion provided on the frame of the box. In addition, the second position of the second conveying roller when the box is removed from the device body can be said to be a position where the locking portion and the locked portion are locked. In addition, it can be said that the holding portion holds the second conveying roller so that the second conveying roller can move to the second position by its own weight.

[0088] like Figure 7BAs shown, the locking hook portion 3222 is locked in a locking hook receiving hole 4101 formed in the drum cartridge frame 410. The locking hook portion 3222 and the locking hook receiving hole 4101 engage with each other to limit the relative movement between the driven roller bearing 3221 (the second conveying roller 322) and the drum cartridge frame 410 (the drum cartridge 41) in the front-rear direction and the left-right direction. In addition, the locking hook portion 3222 and the locking hook receiving hole 4101 are configured to limit the relative movement of the driven roller bearing 3221 (the second conveying roller 322) and the drum cartridge frame 410 (the drum cartridge 41) in the up-down direction within a predetermined range. In addition, the device body 1 is provided with a second conveying roller pressure spring 14, and when the drum cartridge 41 is attached to the device body 1, the driven roller bearing 3221 is pressed by the second conveying roller pressure spring 14. The second conveying roller pressurizing spring 14 biases the driven roller bearing 3221, thereby causing the second conveying roller 322 to move in a direction opposite to the direction of moving away from the second position where the locking hook portion 3222 and the locking hook receiving hole 4101 are locked with each other (i.e., in a direction toward the second position). The second conveying roller 322, which has received the biasing force of the second conveying roller pressurizing spring 14, contacts the first conveying roller 321 before reaching the second position. This position is the first position. The second conveying roller pressurizing spring 14 presses the driven roller bearing 3221, thereby pressing the second conveying roller 322 against the first conveying roller 321 provided in the device body 1 with a predetermined pressure. At this time, the locking hook portion 3222 and the locking hook receiving hole 4101 are spaced apart from each other (in a non-locked state where the upward and downward movement of the driven roller bearing 3221 relative to the drum cartridge frame 410 is not restricted).

[0089] That is, it can be said that the holding portion in the present invention performs holding so that the second conveying roller can move in the direction of moving away from the second position along the direction in which the first conveying roller and the second conveying roller are opposite to each other by contacting with the first conveying roller. In addition, it can be said that the biasing member applies a biasing force to the bearing, thereby moving the second conveying roller in the direction opposite to the above-mentioned moving away direction when the box is attached to the device body. In addition, it can be said that the second conveying roller is held in the first position by the biasing force received by the bearing from the biasing member while the box is attached to the device body.

[0090] FIG. 8A to FIG. 8D 1 is a partially enlarged schematic diagram showing the moving path of the driven roller bearing 3221 when the drum cartridge 41 is attached to the apparatus body 1. Fig. 8A , Figure 8B , Figure 8C and Fig.8D The sequence shows the state in which the drum cartridge 41 gradually moves backward in the apparatus body 1.

[0091] like Fig. 8A As shown, when the drum cartridge 41 is attached to the apparatus body 1, as described above (as shown in FIG. Figure 4A and Figure 4B As shown in FIG. 1 , the moving path of the drum cartridge 41 is restricted by the cartridge guide 12. Fig. 8A As shown, the locking hook portion 3222 and the locking hook receiving hole 4101 are in contact with each other (the locking hook portion 3222 is locked to the edge of the locking hook receiving hole 4101 and the second conveying roller 322 is suspended from the drum cartridge frame 410). Note that Fig. 8A The dotted line in Fig. 8A The moving path of the second conveying roller 322 in FIG.

[0092] like Figure 8B As shown, as the insertion operation of the drum cartridge 41 continues, the second conveying roller guide 13 and the driven roller bearing 3221 engage with each other (the driven roller bearing 3221 engages with the second conveying roller guide 13). When the insertion operation is further advanced, the moving path of the driven roller bearing 3221 is restricted by the second conveying roller guide 13 (the driven roller bearing 3221 moves while sliding on the second conveying roller guide 13). That is, as Figure 8B As shown, the locking hook portion 3222 moves away from the locking hook receiving hole 4101 (enters an unlocked state in which the second transport roller 322 is released from a state in which the second transport roller 322 is suspended on the drum cartridge frame 410).

[0093] like Figure 8C As shown in FIG. 1 , when the insertion operation continues, the driven roller bearing 3221 whose moving path is restricted by the second conveying roller guide 13 engages with the second conveying roller pressurizing spring 14 (receives the biasing force of the second conveying roller pressurizing spring 14). Since the moving path of the driven roller bearing 3221 is restricted by the second conveying roller guide 13, the driven roller bearing 3221 continues to move against the biasing force of the second conveying roller pressurizing spring 14, and as shown in FIG. Figure 8C The second conveying roller pressing spring 14 is pushed up as indicated by the two-dot chain line in FIG.

[0094] like Fig.8D As shown, when the drum cartridge 41 is located at a predetermined position, the moving path of the second conveying roller 322 becomes as follows: Fig.8D At this time, the second transport roller 322 is no longer restricted by the second transport roller guide 13, and is pressed toward the first transport roller 321 by the biasing force of the second transport roller pressing spring 14. Moreover, the locking hook portion 3222 is maintained in a state of being spaced apart from the locking hook receiving hole 4101 (an unlocked state in which the second transport roller 322 is released from a state in which the second transport roller 322 is suspended on the drum cartridge frame 410).

[0095] The above has been referred to Figures 8A to 8D The moving path of the second conveying roller 322 when the drum cartridge 41 is attached is described. Fig.8D , Figure 8C , Figure 8B and Fig. 8A That is, by moving from Fig.8D The state shown in FIG. 1 (which shows a state in which the drum cartridge 41 is completely attached to the apparatus body 1) is shown in FIG. 1 , and the drum cartridge 41 is moved obliquely forward and upward, and can be returned to the state shown in FIG. Figure 8C , Figure 8B and Fig. 8A Status shown.

[0096] As described above, when the drum cartridge 41 is attached to the apparatus body 1, the second conveying roller 322 can move in the up-down direction within the drum cartridge frame 410. That is, the locking hook portion 3222 and the locking hook receiving hole 4101 engage with each other, thereby allowing relative movement between the second conveying roller 322 (driven roller bearing 3221) and the drum cartridge 41 (drum cartridge frame 410) in the up-down direction within a predetermined range. With this configuration, when the drum cartridge 41 is attached to and detached from the apparatus body, the second conveying roller 322 does not hinder the attaching and detaching operations.

[0097] Furthermore, by including the second conveying roller pressing spring 14 in the apparatus main body 1, that is, by providing a part of the configuration for positioning the second conveying roller 322 in the apparatus main body 1, the cost of the drum cartridge 41 can be reduced. That is, when the drum cartridge 41 is attached to the apparatus main body 1, the positioning of the second conveying roller 322 relative to the first conveying roller 321 in the front-rear direction and the left-right direction is performed by the engagement between the locking hook portion 3222 and the locking hook receiving hole 4101. Furthermore, when the drum cartridge 41 is attached to the apparatus main body 1, the positioning of the second conveying roller 322 relative to the first conveying roller 321 in the up-down direction is performed by the bias of the second conveying roller pressing spring 14. Among these positioning units, the second conveying roller pressing spring 14 is provided in the apparatus main body 1. As described above, the drum cartridge 41 is a unit that is replaced when it reaches a predetermined life. The life of the drum cartridge 41 is short compared to the product life of the apparatus main body 1. By reducing the cost of the drum cartridge 41, cost reduction is effective when the total cost until the end of the product life is considered.

[0098] Paper powder recovery structure

[0099] Will refer to Fig. 9 Describe the paper dust recovery structure. Fig. 9 It is a partial schematic diagram of the first conveying roller 321 , the drum cartridge 41 , and the developing cartridge 42 .

[0100] Here, paper dust includes fillers, pulp, originally attached foreign matter, etc. contained in the recording material S. In addition, although the paper dust recovery structure is described as a typical example of the foreign matter recovery structure, the objects recovered by the foreign matter recovery structure are not limited to paper dust.

[0101] like Fig. 9 As shown, a cleaning portion 414, a recovery portion 415, and a downstream conveying paper powder recovery portion 417 are assembled in a drum cartridge frame 410. The cleaning portion 414 is composed of a cleaning roller 4141 and a separation roller 4142. The recovery portion 415 is composed of a recovery pad 4151 and a recovery container 4152. In addition, the downstream conveying paper powder recovery portion 417 is composed of a conveying recovery scraper 4171, a conveying paper powder storage portion 4172, a front side contact member 4173, and a rear side contact member 4174.

[0102] Recovering paper powder from the photosensitive drum

[0103] Will refer to Fig. 9 The recovery of the paper dust attached to the photosensitive drum 411 is described. As described in the above "image forming portion", when the developer image formed on the photosensitive drum 411 is transferred, the recording material S is held at the nip portion between the photosensitive drum 411 and the transfer roller 413. At this time, some of the paper dust attached to the recording material S may be attached to the photosensitive drum 411. These paper dusts are removed from the photosensitive drum 411 by the cleaning portion 414 and recovered by the recovery portion 415.

[0104] The cleaning section 414 is composed of a cleaning roller 4141 as a cleaning member and a separation roller 4142 as a separation member. The recovery section 415 is composed of a recovery pad 4151 and a recovery container 4152, the recovery pad 4151 is a member for recovering paper powder attached to the separation roller 4142, and the recovery container 4152 is a member for storing the recovered paper powder.

[0105] The cleaning portion 414 will be described. The cleaning roller 4141 is a roller obtained by winding an elastic member such as a sponge around a metal shaft. The separation roller 4142 is a metal roller. The cleaning roller 4141 is in contact with the photosensitive drum 411. The separation roller 4142 is in contact with the cleaning roller 4141.

[0106] The cleaning roller 4141 is capable of cleaning the paper dust attached to the photosensitive drum 411 (removing the paper dust from the photosensitive drum 411). More specifically, a bias is applied to the cleaning roller 4141 by a bias applying unit (not shown) to generate a potential difference between the cleaning roller 4141 and the photosensitive drum 411. For example, if a potential difference is generated so that the potential of the cleaning roller 4141 is more biased toward the positive side than the potential of the photosensitive drum 411, negatively charged paper dust can be attracted to the cleaning roller 4141 and recovered. In addition, if a potential difference is generated so that the potential of the cleaning roller 4141 is more biased toward the negative side than the potential of the photosensitive drum 411, positively charged paper dust can be attracted to the cleaning roller 4141 and recovered.

[0107] The paper dust cleaned by the cleaning roller 4141 is separated by the separation roller 4142. A bias is applied to the separation roller 4142 by a bias applying unit (not shown). By providing a potential difference between the cleaning roller 4141 and the separation roller 4142, the paper dust on the cleaning roller can be separated. For example, if the developer is positively charged and the paper dust is negatively charged, by generating a potential difference so that the potential of the separation roller 4142 is more biased to the positive side than the potential of the cleaning roller 4141, the paper dust can be effectively separated.

[0108] The recovery portion 415 will be described. The recovery pad 4151 is a sponge member. Further, the recovery pad 4151 is in contact with the separation roller 4142. The paper powder on the separation roller 4142 is scraped off by the recovery pad 4151 and recovered in the recovery container 4152.

[0109] As described above, paper dust attached to the photosensitive drum 411 is removed by the cleaning portion 414 assembled in the drum cartridge 41 and recovered by the recovery portion 415 .

[0110] Recovery of paper dust from recording materials

[0111] Will refer to Fig. 9 The recovery of paper dust from the recording material S is described. As described above in the "Paper Feeding Section and Conveying Section", the recording material S fed from the paper feeding section 2 is conveyed to the downstream conveying roller section 32, and is sandwiched between the first conveying roller 321 and the second conveying roller 322. Since the developer image is formed on the surface of the recording material S in contact with the second conveying roller 322, it is preferable to remove the paper dust before the photosensitive drum 411 and the recording material S come into contact with each other.

[0112] like Fig. 9 As shown, the conveying recovery scraper 4171 as a paper powder recovery member (foreign matter removal member) contacts the surface of the second conveying roller 322 and removes the paper powder attached to the surface of the second conveying roller 322. The conveying recovery scraper 4171 is a sheet-like member, and a flexible material such as PET can be selected. The conveying paper powder storage part 4172 as a paper powder storage part (foreign matter storage part) is a space formed in the drum box frame 410. The front side contact member 4173 as a front side paper powder leakage prevention member (front side foreign matter leakage prevention member) and the rear side contact member 4174 as a rear side paper powder leakage prevention member (rear side foreign matter leakage prevention member) each have one end fixed by being attached to the conveying paper powder storage part 4172. The other end is a free end and contacts the second conveying roller 322.

[0113] like Fig. 9As shown, the conveying recovery scraper 4171 can scrape off the paper dust attached to the surface by making the edge portion of its distal end contact with the second conveying roller 322. In addition, the front side contact member 4173 and the rear side contact member 4174 prevent the paper dust from leaking to the outside from the conveying paper dust storage part 4172 by contacting the second conveying roller 322.

[0114] Next, the paper dust recovering operation in the downstream conveying paper dust recovering portion 417 will be described in detail.

[0115] The second conveying roller 322 can be configured to include, for example, a roller body made of metal and a coating layer made of fluorine resin covering the outer peripheral surface of the roller body. The second conveying roller 322 is negatively charged by friction due to the action of fluorine in the coating layer during contact (sliding) with the conveying recovery scraper 4171, the front side contact member 4173, and the rear side contact member 4174. As a result, the second conveying roller 322 can attract positively charged paper powder attached to the surface of the recording material S.

[0116] Alternatively, the raw material of the coating of the second conveying roller 322 may also be nylon (registered trademark). In this case, the second conveying roller 322 is positively charged by friction due to the action of nylon (registered trademark) in the coating during contact with the conveying recovery scraper 4171, the front side contact member 4173, and the rear side contact member 4174. As a result, the second conveying roller 322 can attract negatively charged paper powder attached to the surface of the recording material S.

[0117] In addition, if Fig.8DAs shown, a bias applying unit 140 constituted by a high voltage power source or the like provided in the apparatus body 1 is connected to the above-mentioned second conveying roller pressure spring 14. The bias applying unit 140 is a unit for applying a bias to the second conveying roller 322 to generate a potential difference between the second conveying roller 322 and the first conveying roller 321. The bias applied by the bias applying unit 140 can be applied to the second conveying roller 322 via the second conveying roller pressure spring 14 and the driven roller bearing 3221. By using a rubber roller with a metal shaft as the first conveying roller 321 and electrically connecting it to the ground, an electric field caused by a potential difference is generated between the second conveying roller 322 and the first conveying roller 321 due to the applied bias. In this case, the second conveying roller 322 does not necessarily need a coating. For example, when the applied bias is positive, negatively charged paper powder on the surface of the recording material S can be attracted to the second conveying roller 322. By applying a negative bias, positively charged paper powder can be attracted. In addition, the polarity of the applied bias voltage may be switched depending on whether or not the recording material S passes through the nip portion of the downstream conveying roller portion 32. For example, when no recording material S passes through the nip portion of the downstream conveying roller portion 32, by switching the polarity of the bias voltage applied to the second conveying roller 322, paper dust attached to the surface of the first conveying roller 321 may be attracted to the second conveying roller 322.

[0118] In this way, the second conveying roller 322 can attract the paper powder attached to the surface of the recording material S by the action of friction charging or the applied bias voltage. The attracted paper powder rotates while remaining attached to the surface of the second conveying roller 322. Depending on the material of the recording material S used for image formation, etc., it can be appropriately selected whether to charge the second conveying roller 322 positively or negatively. For example, when using a recording material containing a large amount of talc, it is desirable to charge the second conveying roller 322 positively because the talc tends to be negatively charged. In addition, in the case where the recording material contains a large amount of calcium carbonate, it is desirable to charge the second conveying roller 322 negatively because the calcium carbonate tends to be positively charged.

[0119] Here, in the method utilizing the charging ability of the coating material of the second conveying roller 322, the charging polarity depends on the selected material. However, since a unit for applying a bias voltage is not required, the cost can be reduced. In addition, in this example, a configuration has been described in which a coating is provided on the surface layer of the second conveying roller 322 to attract paper powder by a friction charging effect. However, as long as the friction charging effect can be obtained, any configuration other than a configuration including a coating can be used. Examples include a configuration in which the second conveying roller 322 is integrally molded by a resin, and a configuration in which a resin roller is attached to a metal shaft.

[0120] The method of applying a bias voltage increases the degree of freedom in selecting polarity. In addition, since the bias voltage application time can be changed, it is expected that the paper dust recovery capability can be improved.

[0121] The paper dust attracted to the second conveying roller 322 is removed from the second conveying roller 322 by the conveying recovery scraper 4171. Fig. 9 As shown, one end of the conveying recovery scraper 4171 is fixed to the drum box frame 410, and the other end thereof is a free end. Fig. 9 The distal end of the free end faces backward. The distal end of the free end side contacts the second conveying roller 322. Fig. 9 In the embodiment of the present invention, the second conveying roller 322 rotates clockwise. That is, the conveying recovery scraper 4171 contacts the surface of the second conveying roller 322 in the reverse direction. Due to this contact in the reverse direction, the conveying recovery scraper 4171 can obtain sufficient contact pressure against the second conveying roller 322. Therefore, the paper dust on the second conveying roller 322 can be effectively scraped off.

[0122] The conveying paper dust storage portion 4172 is a space for recovering the paper dust scraped off by the conveying recovery scraper 4171. Fig. 9 As shown, one end of each of the front side contact member 4173 and the rear side contact member 4174 to be described below is fixed to the drum cartridge frame 410, and the other end is in contact with the second conveying roller 322. The conveying paper powder storage portion 4172 is formed by a space defined by the front side contact member 4173, the rear side contact member 4174, and the second conveying roller 322. The contact position between the free end of the conveying recovery scraper 4171 and the second conveying roller 322 is located inside the space. The paper powder attached to the second conveying roller 322 is scraped off by the free end of the conveying recovery scraper 4171 and is stored inside the conveying paper powder storage portion 4172.

[0123] As described above, in this example, paper dust attached to the photosensitive drum 411 is cleaned by the cleaning portion 414 and recovered by the recovery portion 415. Further, paper dust conveyed by the conveying portion 3 and attached to the recording material S is recovered by the downstream conveying paper dust recovery portion 417.

[0124] Paper powder leakage prevention member

[0125] Will refer to Fig. 10A and 10B The front side contact member 4173 and the rear side contact member 4174 are described. Fig. 10A and 10B 3 is a partial cross-sectional view showing the positional relationship between the downstream transport paper dust recovery portion 417 and the second transport roller 322 . Fig. 10A shows a state where the drum cartridge 41 is attached to the apparatus body 1, and Fig. 10B A state in which the drum cartridge 41 is outside the apparatus main body 1 (a state in which the drum cartridge is detached from the apparatus main body 1 ) is shown.

[0126] As described above in “Moving path of the second conveying roller when attaching and detaching the drum cartridge”, the second conveying roller 322 moves within the drum cartridge 41. When the drum cartridge 41 is attached to the apparatus body 1, the second conveying roller 322 is in a Fig. 10A When the drum cartridge 41 is removed from the apparatus body 1, the second conveying roller is in the position shown in FIG. Fig. 10B The position shown (hereinafter referred to as the second position). Fig. 10A As shown, when the second conveying roller 322 is in the first position, the second conveying roller 322 is in contact with the conveying recovery scraper 4171, and is in contact with the front side contact member 4173 and the rear side contact member 4174. Fig. 10B As shown, when the second conveying roller 322 is in the second position, the second conveying roller 322 is not in contact with the conveying recovery scraper 4171, but is in contact with the front side contact member 4173 and the rear side contact member 4174. In this way, regardless of whether the second conveying roller 322 is in the first position or in the second position, the front side contact member 4173 and the rear side contact member 4174 are kept in contact with the second conveying roller 322. Therefore, regardless of whether the drum cartridge 41 is attached to or detached from the apparatus main body 1, it is possible to prevent the paper dust removed from the second conveying roller 322 by the conveying recovery scraper 4171 from leaking to the outside of the conveying paper dust storage portion 4172.

[0127] In addition, in this example, the front contact member 4173 is a sponge member, and the rear contact member 4174 is a sheet member. In a configuration in which a coating is formed on the second conveying roller 322 and paper powder is attracted by frictional charging, the following effect can be expected by using a sponge member as the rear contact member 4174. That is, the second conveying roller 322 rotates clockwise. By making the sponge member contact the clamping portion of the first conveying roller 321 on the upstream side of the rotation direction of the second conveying roller 322, effective frictional charging can be achieved.

[0128] On the other hand, one end of the rear side contact member 4174 is fixed to the drum box frame 410, and the other end is a sheet member with a free end. In addition, the free end of the rear side contact member 4174 is set to extend along the rotation direction of the second conveying roller 322. That is, the rear side contact member 4174 contacts the surface of the second conveying roller 322 along the positive direction relative to the rotation direction of the second conveying roller 322. When the second conveying roller 322 is in the first position, the rear side contact member 4174 is significantly bent, and when the second conveying roller 322 is in the second position, the rear side contact member 4174 is slightly bent. It is necessary to design the material of the rear side contact member 4174 so as not to scrape off the attracted paper dust when the second conveying roller 322 is in the first position. According to the research conducted by the inventor of the present invention, a flexible sheet member (such as PET with a smooth surface layer or polyurethane rubber with low elasticity) is suitable as the rear side contact member 4174. In particular, it has been found that the polyurethane rubber sheet has a small repulsive force when bent, making it less likely to scrape off paper dust.

[0129] As described above, both the front contact member 4173 and the rear contact member 4174 are kept in contact with the second conveying roller 322 when the second conveying roller 322 is in the first position and when the second conveying roller 322 is in the second position. In addition, the use of a sponge member as the front contact member 4173 makes it possible to effectively attract paper dust by frictional charging. In addition, by using the rear contact member 4174 as a flexible sheet member, paper dust is not scraped off even when the second conveying roller 322 is in the first position.

[0130] That is, by designing the structures of the front side contact member 4173 and the rear side contact member 4174, the performance of the paper powder storage portion can be improved.

[0131] Modification of the conveying paper dust leakage prevention member

[0132] Will refer to Fig.11A and 11B Modifications of the front side contact member 4173 and the rear side contact member 4174 are described. Fig.11A and 11B 2 is a partial cross-sectional view showing the positional relationship between the downstream transport paper dust recovery portions 417 b and 417 c and the second transport roller 322 according to a modification.

[0133] Fig.11A The downstream conveying paper dust recovery portion 417b of Modification 1 is shown, and Fig. 11B The downstream conveying paper powder recovery portion 417c of Modification 2 is shown. Fig.11A and 11B , the second transport roller 322 in the second position is indicated by a two-dot chain line, and the second transport roller 322 in the first position is indicated by a solid line.

[0134] Fig.11A The downstream conveying paper powder recovery part 417b of the variation example 1 shown includes a front contact member 4173b and a rear contact member 4174b, both of which are flexible sheet-like members. In addition, the direction in which the free end of the rear contact member 4174b extends is the direction opposite to the rotation direction of the second conveying roller 322. Therefore, the rear contact member 4174b is set to contact the second conveying roller 322 along the reverse direction. In the example described in the above "conveying paper powder leakage prevention member", when the second conveying roller 322 is in the first position, it is necessary to significantly bend the rear contact member 4174. However, according to variation example 1, the difference between the bending amount of the rear contact member 4174b when the second conveying roller 322 is in the first position and when the second conveying roller 322 is in the second position can be reduced. In addition, the front contact member 4173b is a sheet-like member. Polyurethane rubber can be selected as the material for the sheet-like member. By using urethane rubber as the front-side contact member 4173 b , the coating layer of the second transport roller 322 can be triboelectrically charged.

[0135] Fig. 11B The downstream conveying paper powder recovery part 417c of the variation 2 shown includes a front contact member 4173c and a rear contact member 4174c, both of which are sponge members. The elastic member such as sponge has a high tracking property when contacting the surface of the second conveying roller 322. On the other hand, when a sponge member is used as the rear contact member 4174c, it is necessary to devise a method to prevent the paper powder attached to the second conveying roller 322 from being scraped off. In this variation, this problem is solved by applying a film member with high sliding properties to the surface layer of the rear contact member 4174. Examples of film members with high sliding properties include high molecular weight polyethylene, fluororesin (PTFE), etc.

[0136] That is to say, as Fig.11A and 11B As shown in the modified example, the materials and free end arrangements of the front contact member 4173 and the rear contact member 4174 can be appropriately selected according to the use conditions. The use conditions include various conditions such as whether to scrape off paper powder attached to the surface of the second conveying roller 322, whether the coating of the second conveying roller 322 needs to be triboelectrically charged, cost, and use environment.

[0137] As described above, according to Example 1 of the present invention, the sealing state in the downstream conveying paper powder recovery portion 417 can be well maintained regardless of whether the drum cartridge 41 is attached to or detached from the device body 1. That is, regardless of whether the drum cartridge 41 is attached to or detached from the device body 1, the contact state between the second conveying roller 322, the front side contact member 4173, and the rear side contact member 4174 can be maintained. Therefore, the paper powder removed and recovered from the second conveying roller 322 can be prevented from leaking from the conveying paper powder storage portion 4172. In addition, a flexible sheet or an elastic material such as a sponge can be selected as the material of the front side contact member 4173 and the rear side contact member 4174.

[0138] As described above, according to this example, even if the second conveying roller 322 moves from the first position to the second position when the drum cartridge 41 is removed from the apparatus body 1, leakage of recovered paper dust can be prevented. That is, the performance of the paper dust storage portion storing paper dust removed from the recording material can be improved.

[0139] Example 2

[0140] Will refer to Fig.12 and Fig.13 An image forming apparatus according to Example 2 as a second aspect of the present invention is described. Note that the configuration of the apparatus main body 1 etc. in the image forming apparatus according to Example 2 is the same as that of the apparatus main body 1 etc. in the image forming apparatus according to Example 1, and therefore is denoted by the same reference numerals, and a description thereof will be omitted.

[0141] Conveyor paper powder storage section

[0142] Fig.12 4 is a partial cross-sectional view showing a schematic configuration of the drum cartridge 41 and the developer cartridge 42. Fig.12 As shown, as described in Example 1, the drum cartridge 41 has a drum cartridge frame 410. In addition, a conveying paper powder storage portion 4172 that stores paper powder in the downstream conveying paper powder recovery portion 417 is formed in the drum cartridge frame 410. The developer cartridge 42 has a developer cartridge frame 420, and as described in Example 1, a developing roller 421, a supply roller 423, a conveying paddle 424, and a developer storage portion 425 that stores a developer are integrated by the developer cartridge frame 420. Increasing the volumes of the conveying paper powder storage portion 4172 that stores paper powder and the developer storage portion 425 that stores a developer is effective in extending the life of the drum cartridge 41 and the developer cartridge 42. However, there is a problem in that enlarging these volumes leads to an increase in the size of the device body 1.

[0143] like Fig.12 As shown, the bottom shape of the developing cartridge frame 420 is determined by the configuration of the supply roller 423 and the conveying paddle 424. The details will be described below.

[0144] It is desirable that the supply roller 423 and the developer box frame 420 have a predetermined gap. If the gap is too large, a large amount of developer will remain in the gap. If the gap is too small, the gap may be blocked by the developer, which may hinder the rotation of the supply roller 423 and the circulation of the developer, thereby promoting the degradation of the supply roller 423. Therefore, it is desirable that the shape of the developer box frame 420 near the supply roller 423 is an arc shape (hereinafter referred to as the first arc 4201) concentric with the supply roller 423. According to the research conducted by the inventors of the present invention, it has been found that favorable results can be obtained when the gap is set between 0.5 mm and 2.0 mm.

[0145] In addition, the conveying paddle 424 rotates clockwise around the rotation center 4241. In addition, the conveying paddle 424 has a conveying blade 4242. The conveying blade 4242 is made of a flexible sheet member such as polyethylene terephthalate (PET), polyethylene (PE) or fluororesin (PTFE). In addition, the distal end of the conveying blade 4242 is set to contact with the bottom of the developer storage part 425 formed by the developer box frame 420. By this arrangement, the amount of developer remaining at the bottom of the developer storage part 425 can be reduced. As described above, since the conveying paddle 424 rotates, in order to stabilize the contact between the conveying blade 4242 and the bottom of the developer storage part 425, it is expected that the shape of the bottom of the developer storage part 425 is an arc shape centered on the rotation center 4241 (hereinafter referred to as the second arc 4202). Therefore, the shape of the bottom of the developer box frame 420 is formed by the first arc 4201 (first arc part), the second arc 4202 (second arc part) and the joint part 4203 connecting them. The first arc 4201 has a shape extending along the outer circumference of the supply roller 423. In addition, the second arc 4202 has a shape extending along the rotation path of the conveying paddle 424.

[0146] Fig.13 4 is a partial cross-sectional view showing the schematic configuration of the downstream conveying paper powder recovery portion 417 and the developing box 42. Fig.13 As shown, the second conveying roller 322 is arranged between the supply roller 423 and the conveying paddle 424. More specifically, the second conveying roller 322 is arranged as follows.

[0147] like Fig.13As shown, when viewed in the direction of the rotation axis of the supply roller 423, the imaginary line connecting the rotation center 4231 of the supply roller 423 and the rotation center 4241 of the conveying paddle 424 is the first auxiliary line 43 (first imaginary line). The imaginary line that is orthogonal to the first auxiliary line 43 and passes through the rotation center 4231 of the supply roller 423 is the second auxiliary line 431 (third imaginary line). The imaginary line that is orthogonal to the first auxiliary line 43 and passes through the rotation center 4231 of the conveying paddle 424 is the third auxiliary line 432 (fourth imaginary line). The second conveying roller 322 is arranged between the second auxiliary line 431 and the third auxiliary line 432. In addition, in this example, the conveying paper powder storage portion 4172 is also arranged between the second auxiliary line 431 and the third auxiliary line 432.

[0148] In this example, even if the downstream conveying paper powder recovery part 417 is provided, in order to reduce the increase in the size of the apparatus body 1, the conveying paper powder storage part 4172 of the downstream conveying paper powder recovery part 417 is arranged as described below. The conveying paper powder storage part 4172 is formed in a concave shape adapted to the bottom of the developing cartridge frame 420, and the concave shape is formed at the portion connecting the first arc 4201 and the second arc 4202. More specifically, the conveying paper powder storage part 4172 is provided as described below. The conveying paper powder storage part 4172 has a shape that conforms to the outer shape of the first arc 4201 and the second arc 4202 of the bottom of the developing cartridge frame 420 and the engaging part 4203 as a shape connecting them, and the drum cartridge frame 410 is formed by the concave part 470 that is opposite to them with a predetermined gap therebetween. The configuration of the concave part 470 corresponds to the outer shape of the first arc 4201, the second arc 4202, etc. of the bottom of the developing cartridge frame 420. That is, the concave portion 470 includes a first wall portion 4701 opposite to the second arc 4202 of the bottom of the developing cartridge frame 420, and a second wall portion 4702 opposite to the first arc 4201 and the engaging portion 4203 of the bottom of the developing cartridge frame 420. The conveying paper powder storage portion 4172 is formed by a space defined by the concave portion 470 of the drum cartridge frame 410 formed in this manner, the second conveying roller 322, and the front side contact member 4173 and the rear side contact member 4174 contacting them.

[0149] In particular, the shape of the second arc 4202 affects the conveying paddle 424 and the developer storage portion 425. Therefore, it is desirable that the conveying paper powder storage portion 4172 is set so as not to affect the second arc 4202. In view of this, in this example, the conveying paper powder storage portion 4172 is defined as follows. That is, Fig.13As shown, when viewed in the direction of the rotation axis of the supply roller 423, the imaginary line parallel to the second auxiliary line 431 and passing through the rotation center 322x of the second conveying roller 322 is the third auxiliary line 433 (second imaginary line). Moreover, the conveying paper powder storage part 4172 is divided (divided) into two areas by the third auxiliary line 433, and one of the two areas closer to the conveying paddle 424 is the front side area 4175 as the first area, and the other area closer to the supply roller 423 is defined as the rear side area 4176 as the second area. The front side area 4175 is an area of ​​the conveying paper powder storage part 4172 defined by the first wall part 4701 of the concave part 470. The rear side area 4176 is an area of ​​the conveying paper powder storage part 4172 defined by the second wall part 4702 of the concave part 470. When comparing the cross-sectional areas of the front side area 4175 and the rear side area 4176, the front side area 4175 is defined as having a smaller cross-sectional area. This limitation makes it possible to prevent the second arc 4202 from being affected.

[0150] That is, during the stable developer stirring and conveying by the conveying paddle 424, the shape of the inner wall surface of the developer box frame 420 on which the distal end of the conveying paddle 424 (conveying blade 4242) slides is preferably an arc extending along the rotation path of the conveying paddle 424. This is because the shape of the second arc 4202 extending along the rotation path of the conveying paddle 424 stabilizes the contact between the conveying paddle 424 and the inner wall surface of the developer box frame 420. For example, if the second arc 4202 is changed to a different shape in order to expand the conveying paper powder storage part 4172 toward the developer storage part 425 side, there is a risk that the stability of the developer stirring and conveying by the conveying paddle 424 is adversely affected. The configuration of this example ensures the space and shape of the developer storage part 425, and ensures the paper powder storage space by utilizing the dead space between the second arc 4202 and the first arc 4201. This makes it possible to improve the paper powder recovery capacity without reducing the developer conveying capacity.

[0151] As described above, when the conveying paper dust storage part 4172 is divided into the front area 4175 and the rear area 4176, the influence on the second arc 4202 is reduced by defining the front area 4175 to be small. Therefore, even if the downstream conveying paper dust recovery part 417 is provided, the size increase of the device body 1 can be reduced.

[0152] It is to be noted that although the paper powder storage capacity of the conveying paper powder storage portion 4172 in the downstream conveying paper powder recovery portion 417 is preferably large, even if, for example, the paper powder storage capacity of the conveying paper powder storage portion 4172 is smaller than the paper powder storage capacity of the recovery container 4152 of the recovery portion 415, the image forming apparatus as a whole can be expected to have a sufficient paper powder recovery effect. That is, the downstream conveying paper powder recovery portion 417 can be said to be an auxiliary paper powder recovery unit for the recovery portion 415, or a paper powder recovery unit before the image forming operation, and the downstream conveying paper powder recovery portion 417 does not need to have a large paper powder storage capacity. The paper powder recovered by the recovery portion 415 includes paper powder generated when the recording material S is rubbed at the nip portion between the photosensitive drum 411 and the transfer roller 413, and is different from the paper powder recovered by the downstream conveying paper powder recovery portion 417 in terms of specific composition. Since the paper powder previously carried on the recording material S before image formation is performed is preliminarily recovered in the downstream conveying paper powder recovery portion 417 before entering the clamping portion, the paper powder recovery capacity in the downstream recovery portion 415 can be improved. In addition, by distributing the recovered paper powder between the downstream conveying paper powder recovery portion 417 and the recovery portion 415, the recovery function of the recovery portion 415 can be maintained for a long time. That is, not only the paper powder storage capacity (paper powder sealing capacity) in the downstream conveying paper powder recovery portion 417 described in Example 1 can be improved, but also the overall performance of the paper powder recovery unit of the device can be improved. In addition, by maintaining the size of the conveying paper powder storage portion 4172 in the downstream conveying paper powder recovery portion 417 at a level that can ensure the required minimum paper powder collection capacity, it can help to reduce the size of the box, reduce the increase in the size of the image forming device, etc.

[0153] Fig.14 4 is a partial cross-sectional view showing the schematic configuration of the downstream conveying paper powder recovery portion 417 and the developing box 42. Fig.14 As shown, when viewed in the direction of the rotation axis of the supply roller 423, the imaginary line parallel to the first auxiliary line 43 and passing through the rotation center 322x of the second conveying roller 322 is the fourth auxiliary line 434 (fifth imaginary line). The conveying paper powder storage part 4172 of the downstream conveying paper powder recovery part 417 is formed within the range included in the area between the first auxiliary line 43 and the fourth auxiliary line 434. The dead zone between the second arc 4202 and the first arc 4201 is a space that is more or less generated in the box structure including the conveying paddle 424 and the supply roller 423 used as a stirring member, as in this example. It can be said that the conveying paper powder storage part 4172 of this example has a structure that maximizes the use of this dead zone. It should be noted that, under the premise of effectively utilizing this dead zone, a part of the conveying paper powder storage part 4172 can also protrude to the outside of the fourth auxiliary line 434.

[0154] Fig.15 1 is a partial cross-sectional view showing a cartridge configuration of Modification 3, which is different in the frame structure of the cartridge from Examples 1 and 2. The cartridge configuration of Modification 3 includes a developing cartridge frame 420 having a smaller size than those of Examples 1 and 2.

[0155] In the box configurations of Examples 1 and 2, the developer storage portion 425 is configured to extend beyond the fourth auxiliary line 434. In contrast, in the box configuration of Modification 3, the developer storage portion 425 is configured not to extend beyond the fourth auxiliary line 434. That is, Fig.15 As shown, in the developer box frame 420b of this modification, the second arc 4202b is formed only within a predetermined range adjacent to the joint portion 4203, specifically, within a range included between the first auxiliary line 43 and the fourth auxiliary line 434. In addition, the developer box frame 420b is arranged so that the straight line portion 4204 continuous with the second arc 4202b extends along the fourth auxiliary line 434, so that the developer storage portion 425 does not cross the fourth auxiliary line 434. That is, the developer box frame 420b has a structure that reduces the size of the developer storage portion 425, thereby reducing the size of the box. In such a box structure, a dead zone also occurs between the second arc 4202 and the first arc 4201. It can be said that the transmission paper powder storage portion 4172 of this modification has a structure that maximizes the use of this dead zone.

[0156] As described above, during stable developer stirring and conveying by the conveying paddle 424, the shape of the inner wall surface of the developer cartridge frame 420 on which the distal end of the conveying paddle 424 (conveying blade 4242) slides is preferably an arc surface shape extending along the rotation path of the conveying paddle 424. This is because the shape of the second arc 4202b extending along the rotation path of the conveying paddle 424 stabilizes the contact between the conveying paddle 424 and the inner wall surface of the developer cartridge frame 420. According to the cartridge construction of Modification 3, by forming (maintaining) the second arc 4202b at least in the region connected to the engaging portion 4203, stable developer stirring and conveying by the conveying paddle 424 can be ensured, and the cartridge can be made smaller.

[0157] Other box modes

[0158] Will refer to Fig.16A and 16B Describes other box modes. Fig.16A and 16B : is a partial cross-sectional view showing the box configuration of Modification 4, which has a box mode different from Examples 1 and 2. In addition, Fig.16A There is shown a state in which a developing built-in drum cartridge 45 and a developing cartridge 46 to be described later are joined together. Fig. 16BA state in which the developing built-in drum cartridge 45 and the developing cartridge 46 are separated from each other is shown.

[0159] In the conveying paper powder storage portion of Example 1 and Example 2, as a cartridge mode, an example in which the image forming portion 4 is composed of a unit consisting of a replaceable drum cartridge 41 and a developer cartridge 42 has been described. As a mode of a replaceable unit, a mode in which the drum cartridge 41 and the developer cartridge 42 are combined and integrated together (hereinafter referred to as an integrated drum cartridge) may also be used. An advantage of the integrated drum cartridge is that since the replacement unit is combined into one unit, there is no need to keep a plurality of units in stock. On the other hand, when the drum cartridge 41 and the developer cartridge 42 are divided into a plurality of units, the life of each unit can be optimized, which has the advantage of reducing running costs.

[0160] In addition, reference will be made to Fig.16A and 16B Other box modes are described. Note that the same parts as those in Example 1 are denoted by the same reference numerals, and description thereof is omitted.

[0161] like Fig.16A and 16B As shown, the replaceable unit in Modification 4 is composed of two units, namely, the developing built-in drum cartridge 45 and the developing cartridge 46.

[0162] In the development built-in drum cartridge 45, the photosensitive drum 411, the charging portion 4120, the cleaning portion 4140, the recovery portion 415, the transfer roller 413, the developing roller 421, the developing blade 422, and the supply roller 423 are integrally attached to the cartridge frame 450. Note that the charging portion 412 in Example 1 is a charging unit of the corona charging method, but the charging portion 4120 in Modification 4 adopts a roller charging method. In addition, the cleaning portion 414 in Example 1 is a cleaning member of the roller cleaning method, but the cleaning portion 4140 in Modification 4 adopts a blade cleaning method. Note that in Examples 1 and 2, the roller charging method may be adopted in the charging unit of the drum cartridge 41, and the blade cleaning method may be adopted in the cleaning member.

[0163] In the developing cartridge 46 , the conveying paddle 424 and the developer storage portion 425 are integrally attached to the developing cartridge frame 460 .

[0164] The developer receiving port 451 is formed in the cartridge frame 450. Accordingly, the developer discharging port 461 is formed in the developing cartridge frame 460. Fig.16A As shown, when the developing drum cartridge 45 and the developing cartridge 46 are combined with each other, the developer receiving port 451 and the developer discharging port 461 are configured to face each other. The developer stored in the developer storage portion 425 is transferred to the supply roller 423 by the rotation operation of the transfer paddle 424.

[0165] like Fig. 16B As shown, the built-in developing drum box 45 and the developing box 46 can be separated from each other. When there is no developer in the developing box 46, the user replaces the developing box 46 with a new developing box. The developing box 46 is a simple unit consisting of a conveying paddle 424, a developer storage part 425, a developer stored therein, and a developer discharge port 461. Therefore, compared with the developing box 42, the cost can be reduced. In particular, when images are often formed with patterns that require a large amount of developer, the method using the developing box 46 method is advantageous in terms of running costs. More specifically, the following situation can be imagined. Assume that the amount of developer stored in the developing box 42 is equivalent to 1000 pages of standard images, and the life of the developing roller 421 is also set to 1000 pages. If the image to be formed uses five times the developer of the standard image, the developing box 42 will run out of developer after 200 pages and needs to be replaced. At this time, the developing roller 421 that has not yet reached the end of its life is also replaced. On the other hand, in the method using the developing cartridge 46, the developing roller 421 is disposed in the developing built-in drum cartridge 45 and can be used until the life reaches 1000 pages.

[0166] like Fig.16A and 16B As shown, the downstream conveying paper dust recovery portion 417 can be arranged in the same manner regardless of the mode of the replaceable unit.

[0167] In addition, Fig.16A and 16B In the illustrated variation 4, a paper powder conveying screw 4177 (i.e., a member for conveying paper powder) is disposed in a downstream conveying paper powder recovery portion 417. The paper powder conveying screw 4177 has a spiral fin (not shown). The fin is configured so that the directions of the spiral shapes are opposite to each other with the center portion in the left-right direction as a boundary. By using a drive transmission unit (not shown) to rotationally drive the paper powder conveying screw 4177, the paper powder is conveyed outward in the left-right direction. By conveying the paper powder in the left-right direction by the paper powder conveying screw 4177, the density of the paper powder recovered by the downstream conveying paper powder recovery portion 417 can be increased. By increasing the density of the paper powder, the amount of paper powder recovered by the downstream conveying paper powder recovery portion 417 can be increased. In addition, if the paper powder contains fibers, by conveying the paper powder using the paper powder conveying screw 4177, it is also expected that the fibers become entangled with each other and promote shrinkage so that the paper powder is difficult to leak to the outside.

[0168] As described above, the mode of the replaceable unit in the first aspect and the second aspect of the present invention may be a drum cartridge 41 and a developer cartridge 42. In addition, the mode of the replaceable unit in the first aspect and the second aspect of the present invention may be an integrated drum cartridge. In addition, the mode of the replaceable unit in the first aspect and the second aspect of the present invention may be a developer built-in drum cartridge 45 and a developer cartridge.

[0169] In the first and second aspects of the present invention, the downstream conveying paper dust recovering portion 417 may also be provided with a paper dust conveying member therein.

[0170] As described above, according to this example, even if paper powder is recovered by the second conveying roller 322 and a space for storing the recovered paper powder is provided, the size of the device can be reduced without affecting the shape of the developing cartridge frame 420 .

[0171] In the above example, the image forming apparatus is described to include the recovery portion 415 as a configuration for removing and recovering paper dust from the photosensitive drum 411 , but an image forming apparatus that does not include the recovery portion 415 and includes only the downstream transport paper dust recovery portion 417 may be used.

[0172] In the above example, as the configuration of the image forming apparatus, the case where the present invention is applied to a so-called monochrome printer including a single image forming portion is described, but the present invention can also be applied to a so-called full-color printer including a plurality of image forming portions. That is, the present invention can be applied to an image forming apparatus in which a full-color image can be formed on a recording material because a recording material is conveyed in such a manner as to sequentially access a plurality of image forming portions having different color developers, and developer images of different colors are sequentially transferred to the recording material in a superimposed manner.

[0173] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image forming device for forming an image on a recording material, the image forming device comprising: A device body, wherein the device body has a first conveying roller; as well as a cassette having a second conveying roller which forms a nip portion for conveying a recording material with the first conveying roller, the cassette being configured to be attachable to and detachable from the apparatus main body, wherein the box comprises: a holding portion configured to movably hold the second conveying roller in an opposing direction in which the first conveying roller and the second conveying roller forming the nip portion are opposed to each other; a removing member configured to remove foreign matter from the second conveying roller by contacting the second conveying roller; a storage portion configured to store foreign matter removed by the removing member; and a contact member configured to contact the second conveying roller at a position different from that of the removing member so as to restrict leakage of foreign matter from the storage portion, wherein the apparatus body has a biasing member configured to bias the second conveying roller in a direction toward the first conveying roller when the cassette is attached to the apparatus body, wherein, when the cartridge is attached to the apparatus main body, the second conveying roller is in a first position to form the nip portion by contacting the first conveying roller due to the biasing force of the biasing member, and when the cartridge is detached from the apparatus main body, the second conveying roller is in a second position, and Wherein the contact member is in contact with the second conveying roller both when the second conveying roller is in the first position and when the second conveying roller is in the second position.

2. The image forming apparatus according to claim 1, Wherein the removing member is in contact with the second conveying roller when the second conveying roller is in the first position, and the removing member is not in contact with the second conveying roller when the second conveying roller is in the second position.

3. A cartridge configured to be attachable to and detachable from a device main body of an image forming device having a first conveying roller, the cartridge comprising: a second conveying roller configured to form a nip portion for conveying the recording material with the first conveying roller; a holding portion configured to movably hold the second conveying roller in an opposing direction in which the first conveying roller and the second conveying roller forming the nip portion are opposed to each other; a removing member configured to remove foreign matter from the second conveying roller by contacting the second conveying roller; a storage portion configured to store foreign matter removed by the removing member; as well as a contact member configured to contact the second conveying roller at a position different from that of the removing member so as to restrict leakage of foreign matter from the storage portion, wherein when the cartridge is attached to the apparatus main body, the second conveying roller is in a first position to form the nip portion by contacting the first conveying roller, and when the cartridge is detached from the apparatus main body, the second conveying roller is in a second position, and Wherein the contact member is in contact with the second conveying roller both when the second conveying roller is in the first position and when the second conveying roller is in the second position.

4. The box according to claim 3, Wherein the removing member is in contact with the second conveying roller when the second conveying roller is in the first position, and the removing member is not in contact with the second conveying roller when the second conveying roller is in the second position.

Images