JP3648556B2 - Image forming unit and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming unit and an image forming apparatus that are excellent in operability in attaching and detaching operations to a main body apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is an image forming unit that is used by being mounted on an electrophotographic image forming apparatus.
[0003]
FIG. 10 shows an example of such an image forming unit in a side sectional view. The image forming unit 10 shown in FIG. 1 is formed of a drum set unit 11 and a development set unit 12. The drum setting unit 11 includes a photosensitive drum 13, a drum cover 14, a cleaner 15, and an initialization charging brush 16, and a recording head mounting groove hole 17 is formed in the upper part. When the image forming unit 10 is detached from the main body apparatus (image forming apparatus) and is alone, the drum cover 14 is indicated by a two-dot chain line in the drawing in order to protect the exposed lower portion of the photosensitive drum 13. When the image forming unit 10 is attached to the main body apparatus, it moves to the left position shown by the solid line in FIG. In the main unit, the photosensitive drum 13 rotates in the clockwise direction. The initialization charging brush 16 applies a uniform charge to the peripheral surface of the photosensitive drum 13. A recording head, which is inserted into the recording head mounting groove 17 and arranged on the circumferential surface of the photosensitive drum 13, performs exposure according to an image signal to form an electrostatic latent image.
[0004]
On the other hand, the developing set unit 12 holds a developing roller 19 rotatably in a lower opening of a vertically long casing, and accommodates toner 21 therein. A stirring member 22, a supply roller 23, and a doctor blade 24 are disposed below the toner 21 so as to be buried in the toner 21. The agitating member 22 rotates as indicated by a broken line in the figure, and feeds the toner 21 to the supply roller 23 while agitating. The supply roller 23 presses the developing roller 19 so that the toner 21 sent from the agitating member 22 is fed. The toner is supplied to the circumferential surface of the developing roller 19 by rubbing. The doctor blade 24 in contact with the circumferential surface of the developing roller 19 in the rotational direction gives a frictional charge to the toner 21 to assist the adhesion to the developing roller 19 and regulate the adhered toner layer to a certain thickness. The developing roller 19 transfers the toner 21 supplied from the supply roller 23 to the low potential portion of the electrostatic latent image on the circumferential surface of the photosensitive drum 13 (in the case of reversal development) to form a toner image.
[0005]
FIG. 11 is a side sectional view of a tandem type color image forming apparatus in which a plurality of image forming units 10 as described above are mounted in a multistage manner. As shown in the figure, the color image forming apparatus 30 includes an upper lid 31 on the upper surface of the apparatus main body. Although not visible in the drawing, a power switch, a liquid crystal display device, a plurality of input keys, and the like are provided on the front side of the upper lid 31. A paper cassette 32 is detachably provided at the lower part of the apparatus main body. A large number of sheets are placed and stored in the sheet cassette 32.
[0006]
Inside the apparatus main body, the conveyor belt 33 is arranged in a substantially flat loop shape in the horizontal direction. The driving roller 34 and the driven roller 35 hold both ends of the loop in the horizontal direction. The conveyor belt 33 is driven by the driving roller 34 and the driven roller 35 and circulates in the counterclockwise direction in the figure. Four auxiliary rollers 36 are disposed in pressure contact with the back surface of the upper circulation portion of the conveyor belt 33. The auxiliary roller 36 prevents slack due to the weight of the conveyor belt 33. Further, a tension roller 37 is disposed in pressure contact with the back surface of the lower circulation portion of the conveyor belt 33. The tension roller 37 is urged downward by an urging member (not shown), and the conveyance belt 33 is stretched.
[0007]
Upstream of the conveyance belt 33 (on the right side in the figure), the suction roller 38 is in pressure contact with the driven roller 35 via the conveyance belt 33 and forms a paper carry-in portion. The suction roller 38 presses the conveyance belt 33 while applying an adsorption bias to the paper carried into the paper carry-in section, and electrostatically attracts the paper to the conveyance belt 33. Four image forming units 10 (10a, 10b, 10c, 10d) are arranged in a multistage manner in the paper transport direction (from the right to the left in the figure) above the upper circulation portion of the transport belt 33.
[0008]
The lower portions of the respective photosensitive drums 13 (13a, 13b, 13c, 13d) of the image forming unit 10 are in contact with the upper circulation portion of the conveyance belt 33, and the transfer brush 40 (40a) is formed on the lower surface of the contact portion of the conveyance belt 33. , 40b, 40c, 40d), and a transfer portion is formed there. A recording head 39 (39a, 39b, 39c, 39d) disposed on the back surface of the upper lid 31 is inserted immediately above each photosensitive drum 13 by closing the upper lid 31, and the recording head is moved by the positioning device. It is positioned and disposed in the mounting slot 17 (see FIG. 10). The upper lid 31 opens and closes around a support shaft behind the apparatus main body 30.
[0009]
In the development set section of the four image forming units 10, Y (yellow: yellow), M (magenta: red dye) and C (cyan: greenish blue) color toners that are the three primary colors of subtractive color mixing, and Bk (black: black) toner dedicated to a black print portion such as a character is accommodated.
[0010]
Each of the above-described devices incorporated in the image forming unit 10 includes gears or electrodes (not shown), and each gear is engaged in the image forming unit 10. When the image forming unit 10 is mounted on the apparatus main body 30 as shown in FIG. 11, the electrodes, the support shafts of the photosensitive drums 13, the support shafts of the developing roller 19, etc. Driven together.
[0011]
As described above, the standby roll pair 41 is disposed on the upstream side (right side in the drawing) of the four image forming units 10 and the conveyance belt 33 in the sheet conveyance direction. The uppermost sheet of the paper stored in the paper cassette 32 is taken out for each rotation of the paper supply roller 42 having a semicircular cross section disposed above the paper supply end of the paper cassette 32. The paper is fed upward by the paper feed roller 43, reversed leftward by a conveyance path 44 formed by two guide plates, and supplied toward the standby roll pair 41.
[0012]
Further, a fixing device 45 is disposed downstream of the conveyance belt 33 in the conveyance direction (left side in the drawing). The fixing device 45 includes a pressure roller, a heat generation roller, a peripheral surface cleaning device, an oil application roller, a thermistor, and the like assembled in a heat insulating casing, and heat-fixes the toner image transferred on the paper to the paper surface. On the downstream side of the fixing device 45, a carry-out roll pair 46, a carry-out guide 47, and a paper discharge roll pair 48 are arranged. The sheet on which the toner image has been thermally fixed by the fixing unit 45 is conveyed by the carry-out roll pair 46, guided upward by the carry-out guide 47, and reversed by the paper discharge roll pair 48, with the toner image facing downward, The paper is discharged from the opening 49 onto a paper discharge tray 51 formed by the upper rear of the apparatus main body and the rear part of the upper lid 31.
[0013]
Between the conveying belt 33 and the paper cassette 32, an electrical component 52 on which a predetermined number of circuit boards can be mounted is disposed. A control device (control means) composed of a plurality of electronic components is mounted on the circuit board disposed in the electrical component 52. A fan 53 is disposed behind the electrical unit 52 to discharge heat dissipated from the electrical unit 52 and heat leaked from the fixing unit 45 to the outside of the apparatus.
[0014]
By the way, such a color image forming apparatus is roughly classified into a single drum type and a multi-stage drum type (tandem type) shown in FIG. In the single drum type, a total of four types of toners, Y (yellow) toner, M (magenta) toner, C (cyan) toner, and Bk (black) toner, are transferred onto one page of paper. Printing (image formation) processing is performed for each toner individually. For this reason, the printing process is repeated four times for one page of paper, and therefore a long time is required for the printing process. On the other hand, the tandem type has four times the processing speed as compared with the single drum type because four types of toner are sequentially superimposed and transferred in one process. For this reason, in recent years, color image forming apparatuses having various tandem configurations have been put into practical use in combination with the downsizing of internal apparatuses and the reduction of the cost due to the assembly (unitization).
[0015]
As described above, since the method of making the color image forming apparatus a tandem type has been considered to be put into practical use since very recently, the shape, arrangement, etc. of the apparatuses disposed inside the color image forming apparatus are considered. As for, there is still no fixed thing, and each device has been devised and proposed by trial and error. For example, in the image forming unit 10 described above, in order to cope with a reduction in the installation area of the apparatus main body, the developing kit unit 12 is formed in a vertically long shape, and the volume of the housing 18 is increased to increase the toner 21. In order to increase the storage capacity, the casing 18 is formed so as to be diagonally upward from the bottom so as to cover the drum set portion 11 of the adjacent image forming unit 10 halfway.
[0016]
[Problems to be solved by the invention]
However, the image forming unit 10 has various problems. For example, the lower part of the photosensitive drum of the image forming unit is exposed when it is removed from the main body as described above. The drum cover 14 disposed to protect this surface from accidents such as exposure to light, adhesion of dirt, and damage is an indispensable member. However, the opening and closing operation of the drum cover 14 is left to the manual operation of the operator. For this reason, when the drum cover 14 is opened, it is highly likely that the operator's hand directly contacts the surface of the photosensitive drum. Since human palms and fingertips are always accompanied by considerable sweating, if the operator's hand touches the photosensitive drum surface with a delicate structure, the surface of the photosensitive drum is contaminated by itself, forming and extending an electrostatic latent image. As a result, a problem arises that a problem occurs in the formation of the toner image. Further, since the drum cover 14 is attached to and detached from the main body device with the drum cover 14 opened, the exposed lower surface of the photosensitive drum is unnecessary for other devices in either case of attachment or removal. There is a possibility that it will come into contact. Since the surface of the photosensitive drum has a fine structure, there is a problem that damage that cannot be repaired is easily formed when unnecessary contact with another apparatus occurs. Further, as described above, since the volume of the housing of the image forming unit is increased obliquely upward in order to cope with both the reduction of the occupied area and the increase of the toner capacity, a trouble in operation occurs. .
[0017]
FIG. 12 is a diagram showing the problem. As shown in FIG. 12, when the image forming unit 10 is stored alone, it cannot be placed upright on the storage shelf as shown by the solid line in the figure. In addition, it cannot be temporarily placed upright on the floor or desk during maintenance work. That is, the development set unit 12 that is desired to be stored in an upright state as indicated by a solid line rolls over around the lower right corner 55 of the housing 18 as indicated by a two-dot chain line 12 'in the figure. For this reason, it has the problem that the handling takes time.
[0018]
In addition, when the internal device of the image forming apparatus is unitized in this way, when the unit is discarded as it is, the individual devices assembled in the unit have different lifetimes, so they are still in use. It is uneconomical if possible assembly equipment is inside, and this is unavoidable as a waste of resources. Therefore, in recent years, a unit in which a unit is divided into a plurality of sub units and these are integrated into one unit has begun to be put into practical use. The above-described image forming unit 10 is also configured such that the drum set unit 11 and the development set unit 12 are sub-units that can be separated from each other, and these are combined to form one image forming unit 10. FIG. 12 shows only the development set unit 12. When the drum set unit 11 is united in the state shown in the figure, the lower surface of the photosensitive drum is exposed to the outside obliquely downward to the left, which is extremely undesirable. When the drum cover 14 is divided into two sub-units in this way, the drum cover 14 is an arrangement member for the drum set unit 11, and therefore an operation member for opening and closing the drum cover 14 is provided on the drum set unit 11 side. . on the other hand. When the operator holds the image forming unit 10 and attaches / detaches it to / from the main body apparatus, the developing set unit 12 that is necessarily held is held. Thus, operating the opening / closing operation member of the drum cover 14 provided on the drum set unit 11 side has a problem that the operability is extremely poor.
[0019]
SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming unit in which there is no risk of damaging the photosensitive drum of the image forming unit, the drum cover can be easily opened and closed, and can be stored in a natural state alone. And an image forming apparatus using the same.
[0020]
[Means for Solving the Problems]
The configuration of an image forming unit according to the present invention and an image forming apparatus using the same will be described below.
[0021]
  The invention according to claim 1 includes an image carrier and,A cover member movable between a closed position covering the externally exposed portion of the surface of the image carrier and an open position exposing the externally exposed portion;Cover urging means for urging the cover member to the closed position;A first unit having at least a developing unit for developing a latent image formed on the image carrier;,Support means for detachably supporting the first unit;,The second unit having at least a second unit is separable from the image forming apparatus main body by engaging both units via engaging means provided on both units. Applies to forming units.
[0022]
  The image forming unit of the present invention includes the second unit.,The first unitofEngage with the cover memberPossible and aboveA first position corresponding to the open position of the cover memberWhenMove to the second position corresponding to the closed position of the cover memberFreeWith operating lever meansLever urging means for urging the operating lever means to the second position, locking means for holding the operating lever means at the first position against the urging force of the lever urging means, and the locking means And a lever lock mechanism comprising a lock release means for releasing the lock state, so that the cover member can be opened and closed via the operation lever means when the two units are engaged.Composed.
[0024]
  The lever lock mechanism is, for example, a claim2As described, the moving member provided so as to protrude and retract with respect to the bottom surface of the second unit, the urging means for urging the moving member in the protruding direction, and the movement provided on the moving member. When the member protrudes from the bottom surface, it can be engaged to lock the operation lever means, and when the moving member retracts from the bottom surface, the lock is not engaged with the operation lever means. It is comprised with a nail | claw. The operation lever means is, for example, a claim3As described, when in the second position, the second unit is configured to have a leg function for preventing a fall when the second unit is placed on a plane.
[0025]
  Claim4The image forming apparatus according to the invention includes an image carrier, a cover member movable between a closed position covering an externally exposed portion of the surface of the image carrier and an open position exposing the externally exposed portion, and the cover Cover urging means for urging the member to the closed position;at leastA first unit having a developing unit that develops a latent image formed on the image carrier, and a support unit that detachably supports the first unit.,The first unitofEngage with the cover memberPossible and aboveThe first position corresponding to the open position of the cover memberWhenMove to the second position corresponding to the closed position of the cover memberFreeWith operating lever meansTheLever urging means for urging the operating lever means to the second position; locking means for holding the operating lever means at the first position against the urging force of the lever urging means; and Unlocking means for releasing the lock state, a moving member provided so as to protrude and retract with respect to the bottom surface, an urging means for urging the moving member in the protruding direction, and the moving member provided on the moving member The lock claw is engageable to lock the operation lever means when protruding from the bottom surface, and is disengaged from the operation lever means when the moving member is retracted from the bottom surface. A lever lock mechanism comprising:at leastA second unit having the image forming unit, and an image forming unit mounting unit that detachably mounts the image forming unit that is engaged and integrated through the engaging means provided in the first and second units; An operating member that is provided in the forming unit mounting portion and that operates the unlocking means when the image forming unit is mounted; and a holding member that holds the operating lever means released from the locked state in the first position; It is configured with.
[0026]
  The invention described in claim 5 is premised on an image forming unit having at least a developing unit for developing a latent image formed on an image carrier and detachable from the main body of the image forming apparatus. In the image forming unit of the present invention, the first position when the image forming unit is mounted on the main body of the image forming apparatus is different from the first position, and the image forming unit is overturned when the image forming unit is placed on a plane. Operating lever means movable to a second position functioning as a prevention leg, lever urging means for urging the operating lever means to the second position,It has a locking claw and an unlocking projection, and the unlocking projectionProvided so as to protrude and retract with respect to the bottom surface of the image forming unit., The locking claw, the unlocking projectionWhen protruding from the bottomAnd when the operating lever means is moved to the first position against the urging force of the lever urging means.Operation lever meansEngaging lever meansTheHold in the first positionLocked andAnd the unlocking protrusionRecedes from the bottomWhenIs disengaged from the operating lever means.And arranged in a positional relationship to release the locked state.And a lever lock mechanism.
[0027]
The image forming unit is, for example, a claim6As described, a cover member is provided that is movable between a closed position that covers the externally exposed portion of the surface of the image carrier and an open position that exposes the externally exposed portion, and the operating lever means includes the cover It is comprised so that it may have a function as a cover operation lever which can open and close a member.
[0028]
  The image forming apparatus according to claim 7 is provided in an image forming unit that has at least a developing unit that develops a latent image formed on the image carrier and is detachable from the main body of the image forming apparatus. A first position when the unit is mounted on the image forming apparatus main body and a second position that is different from the first position and functions as a fall prevention leg when the image forming unit is placed on a plane; Movable lever means, and lever biasing means for biasing the control lever means to the second position;It has a locking claw and an unlocking projection, and the unlocking projectionProvided so as to protrude and retract with respect to the bottom surface of the image forming unit., The locking claw, the unlocking projectionWhen protruding from the bottomAnd when the operating lever means is moved to the first position against the urging force of the lever urging means.Operation lever meansEngaging lever meansTheHold in the first positionLocked andAnd the unlocking protrusionRecedes from the bottomWhenIs disengaged from the operating lever means.And arranged in a positional relationship to release the locked state.A lever lock mechanism, an image forming unit mounting portion provided in the image forming apparatus main body and detachably mounting the image forming unit, and provided in the image forming unit mounting portion when the image forming unit is mounted. Unlock aboveEngage with the projecting projection and retract the unlocking projection with respect to the bottom surface.An actuating member for releasing the locked state;,The operating lever means released from the locked stateEngaging lever meansAnd a holding member for holding at the first position.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIGS. 1A, 1B, and 1C are side views of a drum sub unit (first unit) 100 that is one sub unit of the image forming unit in the embodiment. In the figure, the main part is indicated by a solid line and the other part is indicated by a two-dot chain line. As shown in the figure, the drum sub unit 100 includes a drum set casing 101. A photosensitive drum (image carrier) 102 is rotatably supported on the drum set casing 101 via a drum shaft 103. A drum cover (cover member) 104 is disposed along the lower peripheral surface of the photosensitive drum 102.
[0030]
One end of the drum cover 104 is rotatably supported by a cover shaft 106 disposed at the end of the dog-shaped cover holding member 105, and the drum cover 104 is small and is disposed around the cover shaft 106. The movable end 107 a of the torsion spring 107 is constantly urged in the direction of the drum shaft 103, that is, the direction close to the circumferential surface of the photosensitive drum 102. The dog-shaped cover holding member 105 is fixed to a round brim-shaped cover arm 108, and a fixed end 107 b of the small torsion spring 107 is fixed to the cover arm 108. The cover arm 108 is disposed so as to be rotatable concentrically with the drum shaft 103. A large torsion spring (cover urging means) 109 is disposed around the end of the drum shaft 103, and the movable end 109 a of the torsion spring 109 engages with the cover arm 108, The fixed end 109 b is locked to an engaging portion with the drum set casing 101. As a result, the cover arm 108 is always urged counterclockwise by the large torsion spring 109, and when no external force is applied, the locking portion abuts against the stopper member 101a of the set casing 101. Are locked.
[0031]
Accordingly, the drum cover 104 rotates in a direction in which the free end approaches and separates from the circumferential surface of the photosensitive drum 102 around the engagement end with the cover arm 108, and the entire drum cover 104 is rotated. Rotates concentrically with the drum shaft 103 together with the cover arm 108 with respect to the exposed lower peripheral surface. By this rotation, as shown in FIG. 4B, the open position (first position) where the lower peripheral surface of the photosensitive drum 102 is opened, and the lower portion of the photosensitive drum 102 shown in FIG. It moves to one of the closed positions (second positions) that shield the peripheral surface and stops.
[0032]
FIG. 1 (b) shows only the main part related to the drum cover 104 with a solid line as in FIG. 1 (a), and FIG. 1 (c) shows with a two-dot chain line in FIG. 1 (b). The set casing 101 is also indicated by a solid line. As shown in FIG. 3C, the above-described cover arm 108 and the like are disposed inside the set casing 101. FIG. 2C also shows the drum shaft 103 and the drum shaft support portion 101b of the set casing 101 that supports the drum shaft 103.
[0033]
The above-mentioned cover holding member 105 has a U-shaped end portion that supports the drum cover 104 that protrudes outward from the rotating circumferential surface of the drum cover 104, and a semicircular engagement member on the inside thereof. 110 is formed. This semicircular engagement member 110 is engaged with an opening / closing arm of a development sub-unit to be described later.
[0034]
FIG. 2A is a side view of the developing sub unit which is the other sub unit combined with the drum sub unit 100, and FIG. 2B is a plan view thereof. FIGS. 7A and 7B show only the parts necessary for the explanation, and the other components are not shown.
[0035]
FIG. 3A is a diagram showing another part related to the above-described configuration of the development sub-unit, and FIG. 3B is a diagram supplementing a part thereof. 2A and 2B, the development sub-unit (second unit) 200 includes at least a housing (developing device) 201 and a frame (supporting means) 202.
[0036]
Although not particularly illustrated, the housing 201 includes toner, a stirring member, a supply roller, a developing roller, a doctor blade, and the like inside. The casing 201 is formed substantially vertically on the downstream side (left side in the figure) of the arrangement part to the main body device, and the upstream side (right side in the figure) of the arrangement part is slanted from the bottom to a height of about 2/3. It is formed so as to spread outward in the upward direction, and is formed in a shape that draws a slight arc on the downstream side. With this shape, a relatively large amount of toner can be accommodated without increasing the arrangement area. On the other hand, the frame body 202 is for integrally supporting the drum sub unit 100 described above, and is largely protruded integrally on the lower downstream side of the casing 201.
[0037]
The basic form of the developing sub-unit 200 is substantially the same as the developing set unit 12 of the image forming unit 10 shown in FIGS. However, in the present embodiment, the developing sub-unit 200 is provided with various mechanisms that are combined with and engaged with the drum sub-unit 100 and function integrally with the drum sub-unit 100.
[0038]
That is, as shown in FIGS. 2 (a) and 2 (b), the developing sub-unit 200 is rotatably supported by a support shaft 203 disposed near the upper end of the side surface of the housing 201. A lever (operation lever means, biasing means) 204 is provided. The set lever 204 is urged so as to always rotate outward (rightward in the figure) by an urging member (lever urging means) (not shown). When the set lever 204 is rotated outward by this urging force, As will be described in detail later, the leg function for preventing the overturning of the developing sub-unit 200 alone or for preventing the overturning of the image forming unit in which the two sub-units are combined is exhibited. Also, when the pushing operation is performed inward (to the left in the figure) against the urging force of the urging member, or when this pushing is released, a cover operation for opening and closing the drum cover 104 on the united drum sub unit 100 side. Demonstrate the function of a lever. The set lever 204 is formed with a stopper hook 205 inside the free end, and an arm support shaft 206 is disposed above the stopper hook 205. Further, a triangular wing-like projecting member 207 is formed at a right angle to the inner side of the set lever 204, and a guide rib 208 is projected at a right angle to the blade surface at the end of the triangular wing. As will be described in detail later, the guide rib 208 is guided by the guide rail and moves inward when the image forming unit is mounted on the main body apparatus. As a result, the set lever 204 is sequentially rotated inward about the support shaft 203 as indicated by two-dot chain lines 204 ′ and 204 ″ in the figure.
[0039]
An opening / closing arm (moving member) 210 is rotatably engaged with the arm support shaft 206. The open / close arm 210 extends along the lower side surface of the housing 201 and the side surface of the frame body 202, and is disposed between the side cover 211 and the guide plate 212 of the frame body 202. A receiving groove 210a is formed at the upper part of the free end of the opening / closing arm 210 extending toward the frame 202. A guide pin 213 is fixed to the outer side surface of the opening / closing arm 210 where the receiving groove 210a is formed. The guide pin 213 is provided in a guide groove 214 that is formed in the guide plate 212 and draws a downwardly convex arc. The arc formed by the guide groove 214 is formed concentrically with the arc on the lower peripheral surface of the drum sub unit 100 that engages with the frame body 202 and exposed on the photosensitive drum 102. As a result, the free end of the open / close arm 210 where the receiving groove 210 a is formed is guided to the guide groove 214 via the guide pin 213, and the lower part of the photosensitive drum 102 is moved along with the rotation of the set lever 204. When it is along the outer side of the peripheral surface, it protrudes to the downstream side, and when it is, it retracts to the upstream side (see the positions indicated by the two-dot chain lines 210 ″ and 210 ′ and the solid line 210 in the figure). In order to prevent dropping from the guide groove 214, a drop stopper 215 having a diameter larger than the groove width of the guide groove 214 is attached to the side cover 211. The support groove 216 is provided, and the drum 103 shaft of the drum sub unit 100 combined with the development sub unit 200 is fitted into the support groove 216 to be supported. That.
As shown in FIGS. 3A and 3B, a lock lever (lever lock mechanism) 218 having an inverted triangular shape is disposed between the side cover 211 and the guide plate 212. The lock lever 218 has a downstream end portion (left end of an inverted triangle) supported rotatably on a support shaft 219 disposed on the side cover 211. A hook portion (locking means, locking claw) 218a is formed at the free end (right end of the inverted triangle) facing the upstream side of the lock lever 218, and an actuator 218b (lock releasing means) is formed at the lower end. The actuator 218b of the lock lever 218 protrudes downward as shown by the solid line in FIG. 3 (a) when the developing sub-unit 200 is lifted and there is nothing to contact the bottom, and FIG. The stopper pin 221 shown in FIG. As a result, the hook portion 218a of the lock lever 218 engages with the stopper hook 205 at the tip of the set lever 204 that rotates inward to lock the set lever 204. Then, the image forming unit or the developing sub-unit 200 united with both the sub-units is mounted on the unit holding member (operating member) 301 of the base frame, as shown in FIG. When placed on a table or the like, the lock lever 218 moves upward from the position of the broken line (see the two-dot chain line 218 'in FIG. 3A) as shown in FIG. Release the engagement. As a result, the lock of the set lever 204 is released.
[0040]
Next, operations such as storage, uniting, engagement, opening / closing, and mounting of the drum sub unit 100 and the development sub unit 200 configured as described above will be described with reference to FIGS.
[0041]
FIG. 4A is a state diagram of the drum sub unit 100 and the development sub unit 200 immediately before the uniting, and FIG. 4B is a state diagram showing the engagement relationship of both the sub units immediately after the uniting. First, the development sub-unit 200 is placed on the work table 302. In this state, as shown in FIG. 3 (b), the set lever 204 is disengaged from the lock lever 218 and is urged outward by an urging member (not shown). The legs are opened as shown in a) to prevent the developing sub-unit 200 from falling. Here, the drum shaft 103 of the drum sub unit 100 is inserted into the support groove 216 of the frame 202 of the development sub unit 200 to the position indicated by the two-dot chain line 103 ′ to the bottom of the support groove 216, as indicated by the arrow A in the figure. Insert into. Then, a fixing lever (not shown) is closed and the upper part of the drum shaft is pressed and temporarily fixed. This completes the combination of both sub units as an image forming unit. In this state, as shown in FIG. 5B, the drum cover 104 covers the lower peripheral surface of the photosensitive drum, and the receiving groove 210a at the tip of the opening / closing arm 210 of the set lever 204 is covered with the cover of the cover arm 108. Engage with the engaging member 110 of the holding member 105.
[0042]
FIG. 5A is an operation state diagram following the above, and FIG. 5B is an operation state diagram of the cover opening / closing mechanism associated therewith. As shown in FIG. 5A, the housing 201 of the developing sub-unit 200 is slightly lifted with the right hand, and the set lever 204 is pushed inward with the left hand. By this pushing, the set lever 204 is rotated inward with the support shaft 203 as a fulcrum as shown in FIG. 4B, and accordingly, the receiving groove 210a of the open / close arm 210 protrudes toward the frame 202, The engaging member 110 of the cover arm 108 is moved downstream (to the left) against the urging force of the large torsion spring 109 shown in FIG. As a result, the drum cover 104 moves downstream while rotating outward against the urging force of the small torsion spring 107 shown in FIG. As a result, the lower peripheral surface of the photosensitive drum 102 is opened to the outside for the first time. When the image forming unit is lifted to be attached to the main body, the lock lever 218 is rotated downward as shown by the broken line in FIG. 3B, and the set lever in which the hook portion 218a is pushed in. The set lever 204 is locked in the pushed-in position by engaging with the stopper hook 205 of 204. As a result, the left hand can be released.
[0043]
In this way, after the development sub-unit 200 and the drum sub-unit 100 are integrated together, the set lever 204, which is a member on the development sub-unit 200 side, is operated as if it were a single image forming unit from the beginning. Thus, the drum cover 104 on the drum sub unit 100 side can be moved to the open position, and the position can be fixed as it is.
[0044]
FIG. 6 is a view showing a state in which the image forming unit in which the uniting and the lower opening of the photosensitive drum have been completed as described above is mounted on the main body apparatus. In the figure, only the unit holding member 301, the sub frame 303, and the guide portion (holding member) 304 are shown as the main body device. The overall configuration not shown in the figure may be a tandem type color image forming apparatus as shown in FIG. 11, or an image forming apparatus that performs single color printing, that is, mounts only one image forming unit. May be.
[0045]
When the image forming unit in which the unit and the lower part of the photosensitive drum are completely opened is inserted into the image forming apparatus (main body apparatus) from above as shown in FIG. 6, the lock lever 218 is inserted. Immediately before the actuator 218b contacts the unit holding member 301 of the main body device, the guide rib 208 of the set lever 204 is brought into sliding contact with and engaged with the guide portion 304 of the main body device. The guide portion 304 is formed so as to be inclined obliquely from the top to the downstream side, and the guide rib 208 slides and descends on the inclined portion by the insertion. As a result, the mounting of the image forming unit to the main body apparatus is completed, and the actuator 218b is pushed in by the unit holding member 301 of the base frame and moves backward with respect to the bottom surface of the image forming unit, thereby locking the set lever 204. Even after the release, the guide rib 208 is locked to the guide portion 304, so that the pushing position of the set lever 204 (open position of the drum cover 104) is maintained. Therefore, the image forming unit can perform the printing operation without any trouble in the main body apparatus. In FIG. 6, parts not mentioned in the above description are also given some numbers for convenience when referring to the configurations of FIGS. 1 to 3 and the state diagrams of FIGS. 4 and 5. .
[0046]
Next, FIG. 7 shows a mutual relation diagram between the respective operation states described above. In the same figure, state (1) shows a state in which the developing sub unit 200 shown in FIG. 4A is placed on the workbench with the set lever 204 open and the drum sub unit 100 is separated. ing. State (2) is a state in which the combined image forming unit shown in FIG. State (3) shows a state where the combined image forming unit shown in FIG. State (4) shows a state in which the set lever 204 shown in FIG. 5 (b) is pushed in and locked in the open position. State (5) shows a state in which the image forming unit is mounted on the main body device and the lock by the hook portion 218a is released by contact with the unit holding member 301.
[0047]
The state {circle around (1)} indicates a state immediately before the drum sub unit 100 is combined with the developing sub unit 200 as indicated by an arrow B and a state immediately after separation as indicated by an arrow C. This state can transition to state (2). In other words, the state {circle around (2)} is a state after being merged as indicated by an arrow D or a state before separation (a state where separation is possible) as indicated by an arrow E. In addition, the above state (3) is a state where it is lifted from the work table as indicated by an arrow F, and a state where it is removed from the main unit as indicated by an arrow G. From this state, as indicated by the arrow H, it is possible to shift to the state (2), but in this state, it is not possible to immediately shift to the state (5). That is, as indicated by arrow J, after the operation for changing to state (4), it is possible to shift to state (5) as shown by arrow K. Further, from state (4), not only state (5) but also state (2) can be returned as shown by arrow L. This is when the work is interrupted or when it is noticed that it should be redone.
[0048]
It should be noted that state (1) and state (3) are also not shown by arrows, but can be transitioned to each other. That is, the drum sub unit 100 may be attached and detached while the development sub unit 200 is lifted.
[0049]
In the above embodiment, the image forming unit is formed by combining two sub-units. However, the present invention is not limited to this, and the various mechanisms described above are included in the image forming unit in which the drum portion and the developing portion are integrally configured from the beginning. In this case, the image forming unit can be prevented from being overturned.
[0050]
Further, the set lever 204 is manually pushed into the main body device before being attached to the main unit as shown in the state (4) of FIG. 5 (a), (b) or FIG. However, the present invention is not limited to manual work, and can be automatically performed with the attachment to the main unit. This will be described below as another embodiment.
[0051]
FIG. 8 is a diagram illustrating a configuration of a main body device according to another embodiment and a state where an image forming unit is attached / detached, and FIG. 9 is a diagram illustrating a state where the image forming unit is attached to the main body device. In this embodiment, the configuration of the image forming unit is the same as the image forming unit of the previous embodiment. That is, the drum sub unit 100 and the development sub unit 200 described above are combined. In this embodiment, only the configuration of the main body device is slightly different from that of the previous embodiment. In this case as well, the main unit shows only the main part. The overall configuration not shown may be a tandem color image forming apparatus as shown in FIG. 11 or an image forming apparatus equipped with only one image forming unit for performing monochrome printing. May be.
[0052]
As shown in FIG. 8, in the main body apparatus, a drum shaft holding groove 306 for holding the drum shaft 103 of the photosensitive drum 102 of the image forming unit is formed in the base frame 305, and adjacent to the drum shaft holding groove 306. Also, a roller shaft holding groove 307 for supporting the support shaft 222 of the developing roller of the image forming unit is formed. The upstream side of the roller shaft holding groove 307 also serves as a guide rail 308. The guide rail 308 is formed so as to incline with a predetermined curve on the oblique downstream side from the upper end of the base frame 305 of the main body device to the roller shaft holding portion 309 at the bottom of the roller shaft holding groove 307. The guide rib 208 of the set lever 204 is in sliding contact with the inclined upper surface when the image forming unit is mounted.
[0053]
In the image forming unit indicated by the alternate long and short dash line in the drawing, the drum shaft 103 is fitted into the drum shaft holding groove 306, and the bottom of the drum shaft holding groove 306 is moved to the position indicated by the two-dot chain line 103 ″ as indicated by the arrow M in the figure. , The developing roller support shaft 222 is also moved down the roller shaft holding groove 307 and fixed to the bottom roller shaft holding portion 309. At this time, the guide rib of the set lever 204 which was in the open state at the start of the mounting. 208 slides in contact with the guide rail 308 and descends along the curve of the guide rail 308 inclined obliquely downstream, and when the image forming unit is inserted up to the unit holding member 301 of the base frame 305, FIG. As shown, the guide rib 208 is drawn to the most downstream side of the guide rail 308. As a result, the set tray that has been opened has been opened. -204 is also drawn downstream and pressed against the upstream inclined surface of the development sub-unit 200. In this way, the set lever 204 is automatically moved in the downstream direction as the image forming unit is mounted on the main body. Can be energized.
[0054]
【The invention's effect】
As described above, according to the present invention, the operation member on the one sub unit side of the image forming unit after the unit combination of the sub units is automatically engaged with the cover member of the other sub unit. The cover member on the other sub-unit side can be opened only by the operation on the side, so that the operability is improved. Similarly, the operation member on the one sub unit side of the image forming unit and the cover member of the other sub unit of the image forming unit after uniting the sub units are automatically engaged, so that the cover immediately before the image forming unit is attached to the main body apparatus. The opening operation of the member becomes possible, and therefore, the risk that the operator's hand or the like contacts the surface of the photosensitive drum is greatly reduced. Further, since the cover member can be opened automatically as the main body device is mounted, there is no possibility that the lower surface of the photosensitive drum abuts other devices unnecessarily. Occurrence of problems due to. In addition, since the operation member is opened to serve as a fall prevention member when not attached, the image forming unit or the development sub unit can be placed upright on the work table or stored on a shelf, etc. , Work efficiency is improved.
[Brief description of the drawings]
FIGS. 1A, 1B, and 1C are side views of a drum set (first unit) that is one sub-unit of an image forming unit according to an embodiment.
FIG. 2A is a side view of a development set (second unit) which is the other sub unit combined with the drum set, and FIG. 2B is a plan view thereof.
3A is a diagram showing another part of the development set related to the configuration of FIG. 2, and FIG. 3B is a diagram supplementing a part thereof.
4A is a state diagram immediately before the drum sub unit and the developing sub unit are combined, and FIG. 4B is a state diagram showing the engagement relationship of both the sub units immediately after the combination.
5A is an operation state diagram following FIG. 4, and FIG. 5B is an operation state diagram of the cover opening / closing mechanism associated therewith.
FIG. 6 is a view showing a state in which the image forming unit after the combination and the lower opening of the photosensitive drum are completed is attached to the main body apparatus.
FIG. 7 is a correlation diagram between operation states.
FIG. 8 is a diagram illustrating a configuration of a main body apparatus according to another embodiment and a state where an image forming unit is attached / detached.
FIG. 9 is a diagram illustrating a state in which an image forming unit is mounted on a main body apparatus according to another embodiment.
FIG. 10 is a side sectional view showing an example of a conventional image forming unit.
FIG. 11 is a side sectional view of a tandem type color image forming apparatus in which a plurality of conventional image forming units are mounted in a multistage manner.
FIG. 12 is a diagram illustrating a problem of a conventional image forming unit.
[Explanation of symbols]
10 image forming units
11 Drum set section
12 Development set
13 (13a, 13b, 13c, 13d) Photosensitive drum
14 Drum cover
15 Cleaner
16 Initializing charging brush
17 Recording head mounting slot
18 body
19 Developing roller
21 Toner
22 Stirring member
23 Supply roller
24 Doctor blade
30 Color image forming device (main device)
31 Upper lid
32 Paper cassette
33 Conveyor belt
34 Driving roller
35 Followed roller
36 Auxiliary roller
37 Tension roller
38 Suction roller
39 (39a, 39b, 39c, 39d) Recording head
40 (40a, 40b, 40c, 40d) Transfer brush
41 standby roll pair
42 Feed roller
43 Paper feed roller
44 Conveyance path
45 Fixing device
46 Unloading roll pair
47 Unloading guide
48 Paper discharge roll pair
49 Rear paper exit
51 Output tray
52 Electrical Department
53 fans
55 Lower corner of the body
100 Drum sub unit (first unit)
101 Drum set casing
101a Stopper
101b Drum shaft support
102 Photosensitive drum (image carrier)
103 drum shaft
104 Drum cover
105 Cover holding member
106 Cover shaft
107 Small torsion spring
107a movable end
107b fixed end
108 Cover arm
109 Large torsion spring
109a Movable end
109b Fixed end
110 engaging member
200 Development sub-unit (second unit)
201 Housing (Developer)
202 Frame (supporting means)
203 Support shaft
204 Set lever (operating lever means, biasing means)
205 Stopper hook
206 Arm spindle
207 Overhang member
208 Guide rib
210 Opening and closing arm (moving member)
210a receiving groove
211 Side cover
212 Guide plate
213 Guide pin
214 Guide groove
215 Stopper stopper
216 Support groove
218 Lock lever (lever lock mechanism)
218a Hook (locking means, lock claw)
218b Actuator (lock release means)
219 spindle
221 Stopper pin
222 Developing roller support shaft
301 Unit holding member (actuating member)
302 Work table (or storage shelf, floor, desk, etc.)
303 subframes
304 Guide part (holding member)
306 Drum shaft holding groove
307 Roller shaft holding groove
308 guide rail
309 Roller shaft holder

Claims (7)

An image carrier, a cover member movable between a closed position covering an externally exposed portion of the surface of the image carrier and an open position exposing the externally exposed portion, and biasing the cover member to the closed position A first unit having at least a cover biasing means;
A second unit having at least a developing unit that develops a latent image formed on the image carrier, and a support unit that removably supports the first unit;
In an image forming unit configured to be separable and to be detachable integrally with the image forming apparatus main body by engaging both units via engaging means provided on both units.
A second position corresponding to the open position of the cover member and a second position corresponding to the closed position of the cover member, which is engageable with the cover member of the first unit. A freely movable control lever means,
Lever urging means for urging the operating lever means to the second position;
A locking means for holding the operating lever means in the first position against the urging force of the lever urging means, and a lever locking mechanism comprising a lock releasing means for releasing the locking state of the locking means;
An image forming unit characterized in that the cover member can be opened and closed through the operation lever means when the two units are engaged.  The lever lock mechanism includes a moving member provided to be able to protrude and retract with respect to the bottom surface of the second unit, an urging means for urging the moving member in the protruding direction, and the moving member. When the moving member protrudes from the bottom surface, it can be engaged to lock the operation lever means. When the moving member retracts from the bottom surface, the operation lever means is disengaged. The image forming unit according to claim 1, further comprising a lock claw. It said operating lever means is an image forming unit according to claim 1 or 2, wherein the combine anti-tip legs function when placing the second unit in a plane when in the second position. An image carrier, a cover member movable between a closed position covering an externally exposed portion of the surface of the image carrier and an open position exposing the externally exposed portion, and biasing the cover member to the closed position Cover biasing means;
A first unit having at least
A developing unit that develops a latent image formed on the image carrier, a support unit that detachably supports the first unit, and a cover member that is engageable with the cover member of the first unit; An operating lever means movable to a first position corresponding to the open position of the member and a second position corresponding to the closed position of the cover member, and a lever bias for biasing the operating lever means to the second position Means,
Locking means for holding the operating lever means in the first position against the urging force of the lever urging means, unlocking means for releasing the locked state of the locking means, and protrusion and retraction with respect to the bottom surface A movable member provided, a biasing means for biasing the movable member in the projecting direction, and the operating lever unit in a locked state when the movable member is provided on the movable member and projects from the bottom surface. A lever locking mechanism comprising: a locking claw that can be engaged as much as possible and that is disengaged from the operation lever means when the moving member is retracted from the bottom surface;
A second unit having at least
An image forming unit mounting portion that detachably mounts an image forming unit that is engaged and integrated via engaging means provided in the first and second units, and is provided in the image forming unit mounting portion. An operation member that operates the unlocking means when the image forming unit is mounted, and a holding member that holds the operation lever means released from the locked state in the first position;
An image forming apparatus comprising: In an image forming unit having at least a developing device for developing a latent image formed on an image carrier and being detachable from an image forming apparatus main body,
A first position when the image forming unit is mounted on the main body of the image forming apparatus and a position different from the first position, and functions as a fall prevention leg when the image forming unit is placed on a flat surface. Operation lever means movable to two positions;
Lever urging means for urging the operating lever means to the second position;
A locking claw and an unlocking protrusion, the unlocking protrusion protruding from the bottom surface of the image forming unit so as to be retractable ; and the locking claw is disposed on the bottom surface of the unlocking protrusion . When the operating lever means is moved to the first position when it protrudes and against the urging force of the lever urging means, it engages with the operating lever means, and the operating lever means is moved to the first position. held in a locked state, when the unlocking projection was allowed retracted relative to the bottom surface distribution in a positional relationship to release the locked state I Do and the operating lever means and a disengaged Lever lock mechanism installed ,
An image forming unit comprising:  The image forming unit includes a cover member that is movable between a closed position that covers an externally exposed portion of the surface of the image carrier and an open position that exposes the externally exposed portion, and the operation lever means includes 6. The image forming unit according to claim 5, further comprising a function as a cover operation lever capable of opening and closing the cover member. When the image forming unit is provided in an image forming unit that has at least a developing unit that develops a latent image formed on the image carrier and is detachable from the image forming apparatus main body, and the image forming unit is attached to the image forming apparatus main body. An operation lever means movable to a second position which is different from the first position and functions as a fall prevention leg when the image forming unit is placed on a plane. Lever urging means for urging the operating lever means to the second position, a lock claw and an unlocking protrusion, and the unlocking protrusion is provided so as to protrude and retract with respect to the bottom surface of the image forming unit. The lock claw is moved when the operation lever means is moved to the first position when the unlocking protrusion protrudes from the bottom surface and against the urging force of the lever urging means. the operating lever hand to Engaging the operating lever means is held in the first position and the locked state, when the unlocking projection was allowed retracted relative to said bottom surface and said operating lever means and a disengaged and a lever lock mechanism which is disposed in a positional relationship to release the locked state I Do, the image forming apparatus is provided in the main body, and an image forming unit mounting portion for detachably mounting the image forming unit, the image forming unit An actuating member provided in a mounting portion, which engages with the unlocking protrusion when the image forming unit is mounted , and retracts the unlocking protrusion with respect to the bottom surface ; An image forming apparatus comprising: a holding member that engages with the operation lever unit that is unlocked and holds the operation lever unit in the first position.

Images