JPH0583908B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a developing unit for use in low-cost copying machines or printers, and more particularly to a developing unit that can be thrown away when toner is used up.

BACKGROUND OF THE INVENTION It is known to provide a process kit or cartridge as a unit, which includes a photosensitive drum, a corona discharger, a developer, and a cleaner. Such a unit is removably attached to the main body of an image forming apparatus such as a copying machine or a printer. An example of such a unit is U.S. Pat.
It is disclosed in the specification of No. 4591258.

Japanese Patent Publication No. 56-779 discloses a developing device having a magnetic roller, an inner wall surrounding the roller, and an outer wall located around the inner wall at a distance from the inner wall. These walls define a container filled with toner. forming slits in the container on either side of the magnetic or developer roller to develop the latent image formed on the photoconductor as it passes through the developer;
As the roller rotates, it expels toner from one slit, moves the toner along a development area adjacent the photoconductor, and directs the toner into the other slit. As the toner moves through the development area, it is transferred to the latent image. Although the lid covers the slit, the lid is separated from the slit when loading the developing unit into a copying machine or the like. When the toner is used up, remove the developing device and
Load a new developing device into a copying machine, etc.

All of the known development devices mentioned above are intended for use with monocomponent developers consisting of toner. These development devices do not handle two-component developer mixtures containing carrier particles and toner particles, nor do they incorporate toner into the developer mixture as the toner particles are consumed by development of the latent image on the photoconductor. It also does not replenish particles. Furthermore, development units such as those disclosed in the above-mentioned U.S. patents include other devices in addition to the photoconductor, making the entire device too expensive to be disposable.

DISCLOSURE OF THE INVENTION It is an object of the present invention to have a developer applicator;
To provide a developing unit for a low-cost copying machine or printer, which separately stores a two-component developer mixture and a replenishing toner and is so inexpensive that it can be thrown away when the toner is used up.

The developer unit has an elongated housing made of plastic, which housing has guide means to facilitate its insertion into a copier or printer. A vertically oriented separating wall extends longitudinally of the housing and divides the housing into a first chamber and a second chamber. The first chamber is open at the top, and the second chamber is open at the top.
The chamber has a sloped wall on the side opposite the opening. The toner supply means is located within the opening, and the toner mixing means is located within the first chamber below the toner supply means.
Inlet means below the separating wall allow movement of toner from the second chamber to the first chamber while guiding the toner along the inclined wall.

According to a preferred embodiment, the first and second chambers can be loaded with the necessary components from the top during manufacture and can be closed at the top with a single cover having an opening for a developer applicator. . A simple assembly process involves filling the two chambers with toner and developer mixture, positioning the applicator, and sealing the cover in place.

[Brief explanation of the drawing]

In the following detailed description of the invention, reference is made to the accompanying drawings.

FIG. 1 is an exploded perspective view of a disposable developer unit according to a preferred embodiment of the present invention, showing the positional relationship of FIGS. 1a, 1b, and 1c;
Fig. 2 is an elevational view of the developing unit shown in Fig. 1 seen from the right side, and Fig. 3 is a cross section of the developing unit showing the position of the feed plate in the toner supply chamber immediately after toner is loaded into the toner supply chamber. 4 is a partial cross-sectional view similar to FIG. 3, but shows the position of the feed plate when the toner is used up.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, there is shown at 10 a disposable developer unit of the present invention. This developer unit can be used, for example, in a photoconductor 11 of a copier or printer.
(FIG. 2) can be used to develop the electrostatic latent image on the photoconductor as it passes through the development unit in the direction indicated by the arrows in FIG. The developer unit 10 has an elongated housing 12 assembled from three housing sections 14, 16, 18 extending the length of the unit. The housing portions are molded from a relatively inexpensive plastic material that can be secured together by sonic welding.

The housing has suitable guides to facilitate positioning of the developer unit within the copier or printer. For example, the central housing portion 16
may include a pair of longitudinally extending asymmetrical guides 20, 22 along opposite edges thereof. When the developer unit 10 is loaded into a copier or printer, these guides are accommodated in slots 24 and 26, respectively, of the copier or printer.
Because the guide is asymmetrical, developer unit 10 can only be inserted into a copier or printer from one direction. The left end of the developer unit (FIG. 1) is the inner end of the developer unit, ie, the end that is first inserted into the copier or printer. The operator grasps the handle 28 provided at the right end of the housing portion 16 and
Inserts and removes the developing unit.

The central housing portion 16 has end walls 32, 34
A vertically oriented wall 30 extends the length of the housing therebetween and is spaced from each side wall 36, 38 of the central housing portion. wall 30
The upper edge of the wall 30 is located proximate the inner surface of the upper housing portion 18 and the lower edge of the wall 30 is located adjacent the inner surface of the lower housing portion 1
It is separated from the inner surface of 4. The wall 30 divides the housing into two juxtaposed separate chambers 40, 42;
A space between the lower edge of the wall 30 and the inner surface of the lower housing part communicates the two chambers. Chamber 40 contains toner particles deposited on the latent image on photoconductor 11;
A two-component developer mixture containing carrier particles is housed therein. Meanwhile, chamber 42 contains fresh toner particles for replenishment. As will be discussed below, toner particles are periodically supplied from chamber 42 to chamber 40 to maintain the desired toner concentration within the developer mixture.

The wall 38 of the central housing portion 16 is connected to the guide 2
2 to the lower end of the housing portion 16 and terminating in the bottom wall 44 of the lower housing portion 14. As shown in Figure 2,
Wall portion 38a slopes downwardly and inwardly at a relatively steep slope. This sloped wall portion 38a facilitates the downward movement of toner particles from the upper portion of chamber 42 toward wall 30 and roller 50, thereby avoiding areas where toner may deposit or remain in clumps. prevent the formation of

As best seen in FIG. 3, the bottom wall 44 of the lower housing portion 14 defines a sump 46 as a source of developer mixture. Bottom wall 44 has an elongated semi-cylindrical groove 48 spaced below and spaced from the lower end of vertical wall 30 within housing portion 14 .
Therefore, the groove in the bottom wall 44 and the lower end of the wall 30 form the chamber 42.
A passageway is defined that provides an inlet for fresh toner to be fed from the to the chamber 40 to the chamber 40.

The toner distribution roller 50 is connected to the lower end of the wall 30 and the bottom wall 4.
4 and 48, and substantially fills this passage. Dispensing roller 50 has an elongated cylindrical shaft 52 and a cylindrical layer 54 of foam material covering the shaft, the outer circumferential surface of the layer of foam material meeting the lower edge of wall 30 and the surface of groove 48 in bottom wall 44. are in contact.

As shown in FIG. 1c, the ends of shaft 52 project beyond the ends of layer 54 of foam material. Bearings 56 and 58 are attached to both ends of the shaft 52. Groove 6 in the lower housing part 14
0,62 and the wall 32 of the central housing portion 16,
Corresponding grooves 64, 66 in the bottom of 34 have slots for receiving the annular flanges of the bearing to position the bearing within the housing.

The end of shaft 52, shown on the left side of FIG. 1, projects through a groove 60 in wall 68 of the lower housing section and a groove 64 in wall 32 of the central housing section. This protruding end portion of the shaft has a spline 70 that engages a drive mechanism (not shown) within the copier or printer when the developer unit is fully inserted into the copier or printer. At the other end of the housing there is a substantially semi-circular cover 7
2 protrudes from the end wall 74 of the lower housing portion 14 and covers the lower half of the shaft 52 located within the grooves 62,66. The corresponding cover 75 is the wall 34
protrudes from the outside of the shaft 52 and covers the upper half of the shaft 52. Therefore, the end of the shaft 52 is not exposed at the right end (FIG. 1) or front end of the developer unit. This end is usually the end of the developing unit facing the operator, and covers 72 and 75.
prevents the operator from accidentally touching rotating shaft 52.

As previously mentioned, chamber 40 contains a developer mixture that includes carrier particles and toner particles. Before these particles are delivered to the latent image on the photoconductor,
It is necessary to mix them together to triboelectrically charge the particles. For this purpose, a mixing wheel 8 is installed in the chamber 40.
0 is set. The mixing wheel has an elongated shaft 82 and a plurality of mixing blades 84 secured to and projecting radially outwardly from the shaft. The figure shows three mixing blades 84 positioned at 120° angular intervals around the axis of the shaft 82. Each blade has a plurality of apertures 86 extending from a location adjacent the shaft 52 to a location adjacent the outer edge of the blade to allow a portion of the developer mixture to fall through the apertures during rotation of the blade. It's getting old.

A seal 90 and bearing 92 are located at the left end of shaft 82 (FIG. 1), and a similar seal 94 and bearing 96 are located at the right end of shaft 82. Bearings 92 and 96 fit within grooves 98 and 100 in end walls 68 and 74 of lower housing portion 14, respectively. The bearing is also located in the central housing part 1
It is also housed within a corresponding cylindrical groove 102 in the end wall 32 of 6 and a similar opening in the wall 34 of the housing portion 16 . Flanges on the outer surface of each bearing 92, 96 fit within the grooves of grooves 98, 100, 102 to precisely position the bearing with respect to the housing. The end of the shaft 82 at the front end of the developer unit is covered by a respective cover 101, 103 of the housing parts 14, 16.

As best shown in FIG. 3, a mixing blade 84 is located within the chamber 40 such that when the mixing blade is pivoted, the outer edge of the blade sweeps the inside curved surface 106 of the bottom wall 44 of the lower housing section. It's becoming like that. As the blades pivot, they displace substantially all of the developer mixture within the sump portion 46 of the chamber 40. Blade has curved surface 1
While sweeping 06, a portion of the developer mixture enters the opening 8.
6 to agitate and mix the developer mixture to provide the desired triboelectric mixing of carrier particles and toner particles within the sump. Blade 84 lifts a portion of the developer mixture and moves the developer mixture vertically within chamber 40 toward developer applicator 110 .

The preferred embodiment developer applicator 110 shown in FIGS. 1b and 3 includes a stationary shell 11
A magnetic brush is provided with a rotating magnetic roller 112 located within 4. Magnetic roller 112 may be of conventional construction, having a plurality of magnetic poles extending longitudinally along shaft 116 and alternating north and south poles circumferentially. Still Ciel 114
has a substantially rectangular cross-section, and the walls 118,1
It has 20, 122, 124. Wall 124 is generally semicircular and has a curved portion extending approximately 90 degrees or a quarter circle. Wall 124 is connected to wall 1 at both edges.
18 and the top of wall 122.
As magnetic roller 112 rotates clockwise in FIG. 3, the developer mixture is directed upward along wall 118 and then along wall 124 to wall 122. The developer mixture thus moves along wall 124 in the same direction as photoconductor 11.

Applicator 110 has end caps 128, 130 (first b.
) is supported within the housing portions 16,18. The end caps fit into grooves 132, 134 in housing portion 16 and corresponding grooves 136, 138 in housing portion 18. The end portion of the shaft 116 that projects through the end cap 128 has a plurality of splines 140 that are connected to a drive mechanism (not shown) within the copier or printer for rotating the magnetic roller 112.
can be engaged with. The outer end of the shaft 116 has a groove 134
It is covered by a cover 137 adjacent to the groove 138 and a cover 139 adjacent to the groove 138.

Housing portion 18 provides a cover for the top of the developer unit. The cover has an elongated, substantially rectangular opening 144 (FIG. 1a) that extends substantially the entire length of the cover. The length and width of the opening are determined by the shell 11 of the applicator 110.
It is slightly larger than the length and width of the upper part of 4. The upper portion of the shell projects upwardly through opening 144 and is located adjacent to the photoconductor passing through developer unit 10. The other part of the housing part or cover 18 completely closes the chambers 40, 42 and is fixed to the housing part 16.

The cover and other parts of the housing completely close the chamber 42. Therefore, the housing has chamber 4.
There is no opening for refilling chamber 42 with fresh toner particles after the fresh toner particles initially filled in chamber 2 have been delivered to chamber 40.

As is known in the art, an electrical bias is applied to applicator 110 to control the transfer of toner particles from the applicator to the photoconductor. A conductive metal clip 150 (FIG. 1a) is provided to apply a bias to the applicator. Clip 150 has a base member 152 with legs 154,156. The base member and legs are
Legs 156 extend along wall 118 and are configured to straddle a portion of wall 124 of applicator shell 114. The leg 154 includes a tab 158 projecting therefrom which engages the bottom surface of the housing portion 18 to hold the clip firmly in contact with the applicator shell 114. Clip tongue 160 projects through opening 144 in housing portion 18 and has a flat contact portion 162 that fits within a slot 164 in the outer surface of the left (FIG. 1) or inner end of housing portion 18. Slot 164 is open at the inner end of the developer unit and the sides of the slot project from contact portion 162. When the developing unit of the present invention is loaded into a copying machine or printer, the contact portion 162 is connected to the conductive element 16 in the copying machine or printer.
6. Conductive element 166 is connected to voltage source 168
The bias is connected to element 16 from the voltage source.
6. The shell 114 of the applicator 110 via the contact portion 162 and further via the biasing clip.
is applied to. Although the illustrated voltage source 168 is a DC power source, it may be an AC power source or a combination of a DC power source and an AC power source, if necessary.

Referring to FIGS. 1b, 3, and 4, a feed plate 170 is located within chamber 42 and rests on the toner within the chamber. The length of this plate is substantially equal to the length of chamber 42 and completely fills the gap between walls 32, 34 of central housing portion 16. The width of the feed plate 170 is slightly smaller than the width of the upper part of the chamber 42 (i.e., the part above the inclined wall portion 38a), but it is smaller than the width of the remaining part of the chamber 42 (i.e., the part above the inclined wall portion 38a).
It is wider than the section below the inclined wall section 38a. As the toner in the chamber becomes low by feeding the toner from the bottom of the chamber 42, the feed plate moves down the broad top of the chamber 42 to the bottom of the chamber defined by the vertical wall 30 and the sloped wall portion 38a. enter in.

Plate 170 has a relatively wide section 170a and a narrow section 170b that are connected together by one or more hinges 171. These plate sections may be made of any suitable material such as stainless steel. The hinge is made up of a plurality of ears projecting from plate portion 170b and passing through slots in plate portion 170a, so that plate portion 170
a, 170b can pivot about a hinge.

The feed plate 170 is reliably positioned on a horizontal plane,
It is vertically guided by a pair of guide rails 172, 174 mounted on end walls 32, 34 of housing portion 16. These guide rails are plate 17
0 protrudes through rectangular notches 175 and 177 provided on the trailing and leading edges of the plate, respectively, and is located near the side edge of the plate closest to the wall 30. Therefore, plate 170
The walls 30, 3 are wider by the width of the notches 175, 177 than the corresponding guide rails 172, 174.
It can move in the horizontal plane in the direction toward or away from 8. At the same time, the plate can move freely in the vertical direction without interfering with the guide rail.

The feed plate is biased toward the wall 38, particularly the inclined wall portion 38a, so that as the feed plate moves downward, the plate scrapes off any toner that tends to adhere to the wall portion 38a. desirable. This deflection is accomplished by a guide rail 176 on the right end of wall 30 near wall 34 and a corresponding guide rail 178 on the left end of wall 30 near wall 32. Guide rails 176, 178 slope downwardly toward sloped wall portion 38a. These guide rails define small acute angles with respect to the surface of wall 30. As a result, as the feed plate moves downward by gravity in response to delivery of toner from the bottom of chamber 42, the side edges of the plate closest to wall 30 engage guide rails 176, 178, thereby Press the board towards the wall 30. When the plate portion 170a of the feed plate contacts the inclined wall portion 38a, the plate portion 170a
a pivots around hinge 171, allowing further downward movement of the plate. When the plate portion 170b passes below the lower ends of the guide rails 172, 174, 176, 178, the plate portion 170b is pressed into engagement with the wall 30 due to the contact between the inclined wall portion 38a and the plate portion 170a. . Then, during the downward movement of the feed plate, the side edge of the plate 170
0.38a to substantially scrape off the toner.

FIG. 4 shows the position of plate 170 after substantially all of the toner has been pumped out of chamber 42.
At this point, plate portion 170b is attached to dispensing roller 50.
The plate portion 170a is located at a small acute angle with the wall portion 38a.

Feed plate 170 provides several advantages. First, the weight of the plate acting on top of the toner assists in feeding the toner to the dispensing roller. This is room 4
This is important in ensuring that the toner is delivered to zero.
Additionally, the developer unit 10 can be sufficiently small for use in low cost printers with low utilization rates. The entire developer unit is sealed when the housing portions are adhesively bonded together, allowing the operator to hold the developer unit in any orientation or position prior to loading the developer unit into a copier or printer. As a result, the toner within chamber 42 tends to be primarily offset toward one or the other end of chamber 42 or toward chamber walls 30 or 38. When this condition occurs, the fresh toner delivered from chamber 42 to chamber 40 will not be evenly distributed along the length of chamber 40. This results in
This causes variations in the toner concentration in the length direction of the chamber 40. The weight of the feed plate 170 is
The uniformity of the distribution of fresh toner along the length of the chamber 40 is improved.

Another advantage of plate 170 is that it is nearly impossible to return the feed plate to its original elevated position after the toner has been used up without removing the permanently attached cover 18 of the housing from the developer unit. That's true. Guide rails 172, 17
4,176,178 are plate notches 175,17
7 prevents upward movement of the plate unless the guide rails 172, 714 are accurately aligned with the lower ends of the guide rails 172, 714.
This alignment is extremely difficult to achieve without removing cover 18 and manually manipulating the plates within chamber 42.

The inability of plate 170 to rise to its original position effectively prevents attempts to reuse the disposable developer unit by filling the developer unit with new toner after the original toner has been used up. This is important. The reason is that the toner particles used in the developer unit must be compatible with the carrier particles in chamber 40 and compatible with other elements of the associated copier or printer. This is because it will not happen. Therefore, if incompatible new toner particles are refilled into chamber 42, they may interfere with the proper operation of the developer unit or the entire copier or printer, and may contaminate the same. One method of attempting to refill chamber 42 with fresh toner particles is to form an opening in cover 18 that communicates with chamber 42, inject toner particles into the chamber through this opening, and reseal the opening in cover 18. It is. However, in the developing unit 10 refilled with toner in this way, the toner particles are located above the feed plate 170 and the chamber 4
It does not work properly because the delivery of toner particles to the 0 is blocked.

As is clear from the foregoing description, the entire developer unit is made up of only a few parts, making the developer unit inexpensive and disposable when all of the toner in chamber 42 has been used up. Furthermore, the developer unit can be assembled quickly and easily. In particular, the bearings and seals are positioned over the dispensing roller 50 and the mixing wheel 80, and then the corresponding grooves 60, 6 of the housing portion 14 are positioned.
Load into 2,98,100. The housing part 16 is then placed over this. In this case, the pin 180 in the wall 32 of the housing part 16 is connected to the socket 18 in the wall 68 of the housing part 14.
2 ensures alignment between the housing parts. A similar socket 184 in wall 74 receives a pin 186 in wall 34.
The lower housing portion 14 also has an upstanding wall portion 188 that is connected to the housing portion 16.
is received within a similarly shaped groove 190 in the wall 36 of. Next, assemble the applicator 110,
Located within mounting grooves 132, 134 of housing portion 16. A developer mixture containing carrier particles and toner particles is filled into the chamber 40 before the applicator is placed on the housing portion 16. room 4
2 is filled with toner particles, and the notches 175, 17 are filled with toner particles.
7 is engaged with the guide rails 172, 174, and the feed plate is placed over the toner particles. Then,
An upper housing portion or cover 18 is disposed over housing portion 16 . In this case, the biasing clip 150 is positioned such that the base member 152 is located on the underside of the housing portion 18 such that its legs 154, 156 engage the surface of the shell 114. Clip 150 tongue piece 1
60 protrudes from the opening 144, and the contact portion 162 fits into the groove 164. After the elements have been assembled in this manner, the three housing parts are bonded together, for example by sonic welding, to form a substantially inseparable unit and cannot be disassembled without destroying the developer unit. Therefore, the useful life of the developer unit is limited by the length of the chamber 42 before the housing parts are joined together.
Determined by the initial amount of toner filled into the container.

The first chamber 40 and the second chamber 42 are the applicator 11
0 and the cover 18 is filled from above with a developer mixture and toner particles. This configuration greatly facilitates assembly and allows the lower two housing parts 14, 1 to be used for filling operations in both chambers.
6 can be held in one position by the same holding device. Furthermore, the filling operation of the two chambers can be carried out by means of similarly located and similar equipment.

When the developer unit is loaded into a copier or printer, the drive mechanisms for the dispensing roller 50, mixing wheel 80 and applicator 110 automatically engage the appropriate drivers in the copier or printer.
Also, the electrical bias for the developer unit is connected to the element 166 connected to the voltage source 168 and the contact portion 1
automatically established by engagement with 62.

When applying the developer mixture to the photoconductor,
Mixing wheel 80 and magnetic roller 112 are driven in a constant state. As the mixing wheel 80 sweeps the sump portion 46 of the chamber 40, the mixing wheel mixes the developer mixture within the chamber;
The carrier particles and toner particles are charged triboelectrically. The mixing wheel also delivers a portion of the developer mixture to the applicator 110, where the developer mixture is magnetically held by the magnets of the rollers 112. As roller 112 rotates, the developer mixture moves upwardly along wall 118 and then along wall 124, causing toner particles to contact the photoconductor passing through the developer unit and develop the latent image. . When a toner concentration monitoring device (not shown) senses that the concentration of toner in chamber 40 has reached a predetermined low level, shaft 52 of dispensing roller 50 is caused to rotate to remove fresh toner from chamber 42. The toner is fed into sump 46 where it is mixed with depleted carrier particles. When the originally filled toner is used up, the developer unit is removed from the copier or printer, discarded, and a new developer unit is loaded into the copier or printer.

Although the present invention has been described with reference to preferred embodiments, it goes without saying that various changes and modifications can be made without departing from the gist of the present invention.

Claims (1)

[Scope of Claims] 1. A disposable developing unit for developing an electrostatic latent image, comprising: an elongated housing having a vertical direction extending in the longitudinal direction of the housing and dividing the housing into a first chamber and a second chamber; an inlet, the first chamber and the second chamber being open at the top, the separating wall and the housing permitting movement of toner from the second chamber to the first chamber; a housing defining an opening; a rotationally drivable toner dispensing means for delivering toner from the second chamber to the first chamber; a toner applicator located at the top of the first chamber; and a toner applicator located at the top of the first chamber; carrier and toner charged into the first chamber through an opening; toner filled into the second chamber through an opening in the top; and permanently secured across the tops of the first and second chambers. cover means having an opening located at the top of the first chamber to permit access of the toner applicator to the electrostatic image; covering means for permanently enclosing said housing, said housing comprising a lower housing portion and a central housing portion joined thereon, said central housing portion having said separating wall, said wall comprising said lower housing portion; the toner dispensing means is rotatably supported at the junction of the central housing portion and the lower housing portion and located in the inlet opening; A developing unit characterized in that toner is supplied from the second chamber to the first chamber by rotation. 2. The developing unit according to claim 1, further comprising rotating means for mixing the carrier and toner in the first chamber, and the rotating means is configured to connect the central housing portion and the lower housing portion. A developing unit characterized in that it is rotatably supported by a portion. 3. A method of manufacturing a developing unit according to claim 1, wherein the lower housing part and the central housing part are rotatably supported between the lower housing part and the central housing part. filling the first chamber with carrier and toner from the opening in the top, filling the second chamber with toner from the opening in the top, positioning the toner applicator at the top of the first chamber, and then . A method of manufacturing a developer unit, comprising permanently fixing the cover means across the first chamber and the second chamber.