CN220983727U - Process cartridge and printer - Google Patents

Abstract

The utility model discloses a processing box, which comprises a box body, a developing roller, a powder discharging knife and a powder discharging knife bracket, wherein the developing roller, the powder discharging knife and the powder discharging knife bracket are arranged in the box body; the doctor blade is arranged on the powder outlet knife bracket and is positioned at the upstream of the powder outlet knife in the rotation direction of the developing roller, and a second gap with a fixed width is kept between the doctor blade and the outer peripheral surface of the developing roller; the width of the second gap is greater than the width of the first gap. The utility model also discloses a printer. According to the utility model, the doctor blade is arranged at the upstream of the rotation direction of the developing roller, so that a part of the developer layer on the developing roller can be scraped by the doctor blade before reaching the powder discharge knife, and deformation or fracture caused by overlarge stress of the powder discharge knife is avoided.

Description

Process cartridge and printer

Technical Field

The present utility model relates to a process cartridge and a printer.

Background

The process cartridge is a device provided in the printer apparatus for forming an image of an image forming module.

The imaging module comprises a powder cylinder and a developing assembly:

The developing assembly comprises a box body, wherein a cavity is formed in the box body; the toner in the powder cylinder enters the cavity from the powder inlet, is adhered to the developing roller after being stirred by the stirring screw, is adsorbed on the peripheral surface in the rotating process of the developing roller, and the powder outlet blade is arranged beside the developing roller, forms uniform gaps on the surfaces of the powder outlet blade and the developing roller, and continuously rotates through the powder outlet blade after the toner is adsorbed on the surface of the developing roller, so that a layer of uniform developer layer with the same thickness as the gaps is left on the surface of the developing roller;

The printer equipment is also provided with a laser scanning module, the laser scanning module prints an image to be printed on the surface of the photosensitive drum in the box body, so that the potential of an image area is opposite to that of a blank area, and furthermore, the image area can adsorb the toner on the corresponding developing roller in the process of rotating relative to the developing roller, the blank area can not adsorb the toner, and the image to be printed is formed on the surface of the photosensitive drum;

The photosensitive drum continues to rotate, contacts the printing medium (paper) somewhere after passing the developing roller, and then transfers the image of the photosensitive drum surface onto the printing medium (paper).

In the above-described technique, a large amount of toner may be adsorbed on the developing roller due to the viscosity of the toner, giving a large stress to the blade may cause the blade to deform or even break.

Disclosure of utility model

According to an aspect of the present utility model, there is provided a process cartridge comprising a cartridge body, a developing roller, a doctor blade and a doctor blade holder provided in the cartridge body, both ends of the developing roller being supported on the process cartridge for rotation about an axis, the developing roller adsorbing developer in the cartridge body to form a developer layer on an outer peripheral surface, the doctor blade being held by the doctor blade holder to the side of an outer surface of the developing roller to limit the thickness of the developer layer, the doctor blade and the outer peripheral surface of the developing roller maintaining a first gap of a fixed width;

The doctor blade is further arranged on the powder discharge blade bracket and is positioned at the upstream of the powder discharge blade in the rotation direction of the developing roller, and a second gap with a fixed width is kept between the doctor blade and the outer peripheral surface of the developing roller;

the width of the second gap is greater than the width of the first gap.

According to the processing box, the powder outlet knife in the box body is kept at the side of the outer surface of the developing roller through the powder outlet knife support, and the scraping blade is arranged at the upstream of the powder outlet knife in the rotation direction of the developing roller, so that a part of a developer layer on the developing roller can be scraped by the scraping blade before reaching the powder outlet knife, and deformation or fracture caused by overlarge stress of the powder outlet knife is avoided.

In some embodiments, the powder discharge knife bracket comprises a bracket body and the scraping blade, wherein the scraping blade protrudes out of the bracket body and is connected with the bracket body through connecting ribs, and a gap for toner to overflow is formed between the connecting ribs.

In some embodiments, the doctor blade support includes a first mounting surface providing a first location for defining a mounting location of the doctor blade and a second mounting surface providing a second location for defining a mounting location of the doctor blade support within the box;

the two ends of the powder outlet knife are fixedly connected to the inner wall of the box body.

In some embodiments, a connecting groove is formed in the inner wall of the box body, a first connecting piece is placed in the connecting groove, and the second connecting pieces at two ends of the powder outlet cutter are matched with the first connecting pieces to fix the powder outlet cutter.

In some embodiments, the first positioning part comprises at least two raised positioning posts, and the powder outlet knife is provided with mounting holes corresponding to the positioning posts.

In some embodiments, the first connecting piece is a nut, the second connecting piece is a screw, the nut is enclosed in the connecting groove and can shake relative to the connecting groove but does not break away from the connecting groove, and when the powder outlet knife is installed, the screw penetrates through the powder outlet knife to be connected with the nut, so that the powder outlet knife is fixed.

In some embodiments, the nut is a metal nut, the connecting groove is made of plastic material with a melting point lower than that of the metal nut, and when the metal nut is heated, the inner wall of the connecting groove is melted, so that a gap between the metal nut and the inner wall of the connecting groove is adjusted.

In some embodiments, the doctor blade has a wall thickness that increases gradually in a direction away from the developer roller surface.

In some embodiments, a side of the powder discharging knife away from the developing roller is provided with a bend along a direction of attaching the powder discharging knife support, so that the cross section of the powder discharging knife is L-shaped.

According to another aspect of the present utility model, there is provided a printer including the process cartridge.

According to the printer, the processing box is arranged, the powder outlet knife in the box body is kept at the side of the outer surface of the developing roller through the powder outlet knife support, and the scraping blade is arranged at the upstream of the powder outlet knife in the rotating direction of the developing roller, so that a part of the developer layer on the developing roller can be scraped by the scraping blade before reaching the powder outlet knife, and deformation or fracture caused by overlarge stress of the powder outlet knife is avoided.

Drawings

Fig. 1 is a perspective view of an image forming apparatus in the present utility model;

FIG. 2 is a cross-sectional view of an image forming apparatus according to the present utility model;

FIG. 3 is a cross-sectional view of a developing assembly of the present utility model;

FIG. 4 is a perspective view of an angle of the doctor blade holder of the present utility model;

FIG. 5 is a perspective view of another angle of the doctor blade holder of the present utility model;

FIG. 6 is a perspective view of the assembly of the doctor blade and doctor blade holder of the present utility model;

FIG. 7 is a perspective view of the assembly of the doctor blade and the processing cartridge of the present utility model;

FIG. 8 is a perspective view of the powder discharge blade of the present utility model;

Fig. 9 is a perspective view of a photosensitive drum in the present utility model;

FIG. 10 is a perspective view of a drive gear according to the present utility model;

FIG. 11 is a perspective view of a conductive sheet according to the present utility model;

fig. 12 is a perspective view of a conductive steel shaft according to the present utility model;

fig. 13 is a perspective view of a driving member according to the present utility model.

In the figure: 10. an image forming apparatus; 11. a control module; 12. a frame; 13. a paper feed module; 14. an imaging module; 15. a laser scanning module; 16. a transport module; 100. a powder supply assembly; 200. a developing assembly; 201. a case body; 202. a developing roller; 203. a powder outlet knife; 2031. a mounting hole; 2032. a fastening hole; 204. a powder outlet cutter bracket; 2041. a bracket body; 2042. a wiper blade; 2043. a connecting rib; 2044. a first mounting surface; 2045. a second mounting surface; 2046. positioning columns; 2047. positioning a clamping block; 2048. a nut; 205. a photosensitive drum; 206. a biasing member; 207. a conductive sheet; 208. a conductive steel shaft; 209. a transmission gear; 2010. a spring plate; 2011. a grounding plate; 2012. a driving member; 2013. a right angle driving claw; 2014. a bump; 2015. and a connecting groove.

Detailed Description

The present utility model will now be described in further detail with reference to the accompanying drawings, wherein the embodiments described are some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying a number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and include, for example, either fixedly attached, detachably attached, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium.

In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

The image forming apparatus 10 (printer) generally includes a control module 11, a paper feed module 13, an image forming module 14, a laser scanning module 15, a fixing module, and a conveyance module 16, as shown in fig. 1 and 2. The control module 11 is responsible for controlling the modules of the whole machine. The laser scanning module 15, after receiving the print control command, scans the image forming module 14 with laser light to form an image to be printed, the conveying module 16 takes out the print medium (typically, paper) from the paper feeding module 13 and conveys the print medium to the image forming module 14, the image to be printed is transferred onto paper, and the conveying module 16 continuously conveys the paper with the image to the fixing module to fix the image, so that the image is fixed on the surface of the paper and then discharged.

The specific imaging steps comprise:

In the first step, charging is performed. The surface of the rotating photosensitive drum 205 is charged with a uniform negative charge by a corona assembly or a charging roller.

Second, writing (exposure). The laser beam carrying the digital information scans the surface of the photosensitive drum 205, the surface of the photosensitive drum 205 irradiated with the laser light from the laser scanning module 15 becomes a conductor, the electrostatic charge disappears, and an electrostatic latent image having a different potential is formed on the surface of the photosensitive drum 205.

And thirdly, developing. In the development area, the electrostatic latent image on the surface of the photosensitive drum 205 becomes a visible toner image. The developer formed by mixing the toner and the carrier is first attracted to the surface of the developing roller 202, and a uniform layer of the developer of a specific thickness is formed on the surface of the developing roller 202 under the control of the toner discharging blade 203, and the toner is charged by friction during the mixing of the toner and the carrier. The toner is vibrated on the surface of the magnet roller by the AC/DC bias and transferred to the OPC. The electrostatic latent image area on OPC attracts toner and forms a visible image from the surface.

Fourth, transfer printing. The photosensitive drum 205 carrying the image rotates and encounters the same-speed paper. The transfer roller applies a positive voltage to the back of the paper, causing the negatively charged toner to be attracted to the paper.

And fifthly, fixing. The paper carrying the toner image enters a fixing module composed of a heat roller and a pressure roller. Under the action of heat and pressure, the toner particles are fused into the paper fibers to form what we see.

And sixthly, cleaning. Since the toner on the surface of the photosensitive drum 205 is not 100% transferred to the paper, the powder remaining on the OPC is removed by the cleaning blade and collected in the waste bin.

Seventh, discharge. The surface of the photosensitive drum 205 after transfer is still charged with a small amount of static electricity, and the surface is electrostatically removed by a charging roller for the next development cycle.

In the structure, the image forming apparatus 10 includes a housing 12, the paper feeding module 13, the image forming module 14, the laser scanning module 15, the fixing module, the conveying module 16, and the exterior member that is mounted in the housing 12. The frame 12 is a skeleton portion of the complete machine for mounting, positioning and circuit connection of the respective module components.

Typically, the imaging module 14 is removably mounted within the housing 12. In one possible embodiment, as shown in FIG. 2, imaging module 14 is comprised of two parts, a powder supply assembly 100 (powder cartridge) and a developing assembly 200 (process cartridge).

As shown in the cross-sectional view of the imaging module 14 shown in fig. 3, the toner supply assembly 100 is used to store and supply toner, a carrier is stored in a process cartridge, and toner is discharged from the toner supply assembly 100 through a toner inlet into the developing assembly 200.

The stirring screw is provided in the powder feeding unit 100, and is driven to rotate in the powder cylinder, so that the toner is prevented from adhering to the inner wall of the powder feeding unit 100 and can be smoothly discharged from the powder outlet.

Also provided in the developing assembly 200 are a stirring device, a developing roller 202, a toner discharging blade 203, and a photosensitive drum 205. The stirring device sufficiently mixes the toner and the carrier into the developer. The photosensitive drum 205 and the developing roller 202 are parallel in rotation axis and opposite in rotation direction, and the toner discharging blade 203 is disposed along the axis direction of the developing roller 202 and held at a position forming a gap of a fixed width with the surface of the developing roller 202. The charged surface of the developing roller 202 can absorb developer to form a developer layer, the thickness of the developer layer is uneven under the untreated condition, and the developer layer is uniformly thick after being subjected to gap treatment between the powder discharging knife 203 and the surface of the developing roller 202. The surface of the photosensitive drum 205 is scanned by the laser scanning module 15 to form an electrostatic latent image, that is, an area where an image is formed is charged, and the area is adjacent to the developer layer on the surface of the developing roller 202, and then the toner is adsorbed in the electrostatic area, so that an image is formed on the surface of the photosensitive drum 205.

The process cartridge is a box-like structure in which a cavity is formed, and in which internal devices such as a stirring device, a developing roller 202, a photosensitive drum 205, a doctor blade 203, and the like are mounted. In one embodiment, the process cartridge is composed of a cartridge body 201 with an opening and a cover body, the developing roller 202, the powder discharging knife 203 and the stirring device are all installed in the cartridge body 201, and the cover body closes the opening of the cartridge body 201 to make the inside a relatively sealed cavity. The junction of the cover and the box 201 is glued or closed by a clamping groove structure, and optionally, a ring of sealing sponge is also provided along the inner edge of the glue/clamping groove junction to prevent the carrier from leaking from the junction.

The present utility model relates to an image forming module 14 of an image forming apparatus 10, in which a cartridge as a powder supplying assembly 100 and a process cartridge as a developing assembly 200 are two independent members. The powder discharging knife bracket 204 provides installation positioning for the powder discharging knife 203, and simultaneously provides pretreatment of the developer layer, and the thickness of the developer layer is pre-interfered, so that the thickness of the developer layer passing through the powder discharging knife 203 can be prevented from being too large, and deformation and even fracture caused by too large stress of the powder discharging knife 203 are further avoided.

In one embodiment, as shown in fig. 4 and 5, the doctor blade support 204 includes a support body 2041 and a doctor blade 2042, wherein the doctor blade 2042 protrudes from the support body 2041 and is connected to the support body 2041 by a connecting rib 2043, and a gap for toner to overflow is formed between the connecting ribs 2043. Thereby, the strength of the blade 2042 is increased to reduce the probability of breakage, and toner can overflow through the gap to prevent aggregation.

In one embodiment, the thickness of the blade 2042 increases gradually in a direction away from the surface of the developing roller 202, and even if the blade 2042 has a triangular cross section, such a structure can be advantageous in improving the stability of the structure of the blade 2042, thereby helping to reduce the probability of breakage.

The assembled structure of the doctor blade 203 and the doctor blade holder 204 is shown in fig. 6, the doctor blade 203 is held by the doctor blade holder 204 at the side of the outer surface of the developing roller 202 to limit the thickness of the developer layer, and the doctor blade 203 maintains a first gap of a fixed width with the outer peripheral surface of the developing roller 202; the blade 2042 is located upstream of the doctor blade 203 in the rotational direction of the developing roller 202, and the blade 2042 maintains a second gap of a fixed width with the outer peripheral surface of the developing roller 202; the width of the second gap is greater than the width of the first gap. Even if the developer layer on the developing roller 202 is pretreated by the second gap before reaching the powder discharging knife 203, and then is uniformly thick after being treated by the first gap, the thickness of the developer layer passing through the powder discharging knife 203 is prevented from being too large, and deformation and even fracture caused by too large stress of the powder discharging knife 203 are avoided.

Specifically, a first mounting surface 2044 and a second mounting surface 2045 are formed on the support body 2041 of the doctor blade support 204, a first positioning portion for defining the mounting position of the doctor blade 203 is provided on the first mounting surface 2044, and a second positioning portion for defining the mounting position of the doctor blade support 204 in the case 201 is provided on the second mounting surface 2045. This achieves effective fixation of the doctor blade holder 204 and enables the doctor blade holder 204 to provide effective mounting and positioning of the doctor blade 203.

In one embodiment, the first positioning portion includes at least two protruding positioning posts 2046, and the powder outlet blade 203 is provided with mounting holes 2031 corresponding to the positioning posts 2046, and in a specific implementation, the positioning posts 2046 are mounted on the first mounting surface 2044 of the support body 2041 at intervals, that is, the positioning posts 2046 are mounted in part of the mounting holes 2031 at intervals, thereby improving the positioning effect of the powder outlet blade 203. While the idle mounting hole 2031 may give the doctor blade 203 more deformation, further reducing the probability of breakage.

In one embodiment, the first mounting surface 2044 of the support body 2041 is provided with a plurality of hollow structures along the length direction thereof, and the positioning columns 2046 are arranged between the hollow structures at intervals, so that more allowance for elastic deformation can be provided for the support body 2041.

In one embodiment, the second positioning portion includes at least one positioning block 2047 disposed along the length direction of the support body 2041, and a positioning slot is correspondingly disposed on the inner wall of the box 201, and the positioning block 2047 can be clamped with the positioning slot, so that the second mounting surface 2045 of the support body 2041 can be fastened on the inner wall of the box 201 through the positioning block 2047. In particular, on the second mounting surface 2045 of the support body 2041, two adjacent positioning clamping blocks 2047 are arranged at intervals, which is beneficial to saving material cost, providing more margin for elastic deformation for the support body 2041 and preventing fracture.

As shown in fig. 7, the assembly structure of the powder discharging knife 203 and the processing box is that two ends of the powder discharging knife 203 are fixedly connected to the inner wall of the box body 201, a connecting groove 2015 is arranged on the inner wall of the box body 201, a first connecting piece is arranged in the connecting groove 2015, and two ends of the powder discharging knife 203 are matched with the first connecting piece to fix the powder discharging knife 203. This arrangement facilitates efficient fixing of the doctor blade 203.

The first connecting member is a nut 2048, the second connecting member is a screw, the nut 2048 is enclosed in the connecting groove 2015 and can shake relative to the connecting groove 2015 without being separated from the connecting groove 2015, and when the powder discharging knife 203 is installed, the screw passes through the powder discharging knife 203 to be connected with the nut 2048, so that the powder discharging knife 203 is fixed. Such a mounting manner is simple in structure and facilitates effective fixation of the doctor blade 203.

Specifically, fastening holes 2032 are formed on both ends of the powder discharge blade 203, and a screw is connected to the nut 2048 through the fastening holes 2032 of the powder discharge blade 203, and more specifically, the mounting hole 2031 is located in the middle section of the powder discharge blade 203, i.e., between the two fastening holes 2032. Thus, by properly arranging the structure of the doctor blade 203, the doctor blade 203 can be effectively connected with the doctor blade holder 204 and the case 201, respectively.

In one embodiment, the nut 2048 used to secure the doctor blade 203 is secured to the process cartridge case 201 by a hot melt nut 2048 process. That is, the nut 2048 is placed in the connecting groove 2015, since the nut 2048 is metal and the box 201 is made of plastic material, the inner wall of the connecting groove 2015 is heated and melted by heating the nut 2048, the melted material wraps the nut 2048, and then the nut 2048 is fixedly embedded in the connecting groove 2015 after cooling and solidifying.

In another embodiment, the nut 2048 is pre-inserted into the mold when the case 201 is molded, and is molded once with the case 201.

As shown in fig. 8, the structure of the doctor blade 203 is that the doctor blade 203 is bent along the direction of attaching the doctor blade support 204 away from the developing roller 202, so that the doctor blade 203 has an L-shaped cross section, which is beneficial to improving the deformation resistance.

In the above-described embodiment, the photosensitive drum 205 and the developing roller 202 in the process cartridge need to be provided with conductive structures.

In one possible embodiment, the conductive structure of the photosensitive drum 205 includes a conductive sheet 207 and a conductive steel shaft 208 provided on the apparatus body. The inner wall of the photosensitive drum 205 is communicated with a conductive steel shaft 208 through a conductive sheet 207, and the end part of the conductive steel shaft 208 is communicated with the grounding structure of the equipment, so that the photosensitive drum 205 is grounded.

As shown in fig. 9, the photosensitive drum 205 has a hollow tubular structure as a whole, and a transmission gear 209 is connected to both ends of the photosensitive drum 205, and the transmission gear 209 receives a rotational driving force.

As shown in fig. 10, the transmission gear 209 has a hollow gear shaft portion through which a conductive steel shaft 208 passes, and a conductive sheet 207 is provided on one side of the gear adjacent to the inside of the photosensitive drum 205, and attached to the gear.

As shown in fig. 11, the conductive sheet 207 has a structure of a photosensitive drum 205, and the conductive sheet 207 has a ring-shaped main body. The annular middle hollowed-out area is aligned with the shaft part hollowed-out area of the transmission gear 209 for the conductive steel shaft 208 to pass through. The annular inner edge is provided with an extended elastic sheet 2010, the elastic sheet 2010 is bent towards the axis direction, and when the steel shaft passes through, the elastic sheet 2010 is abutted against the peripheral surface of the steel shaft under the action of self elasticity to realize electric communication.

The outer edge of the conductive sheet 207 has a clamping portion. The flat shape of the clamping part is T-shaped, and can be clamped on the transmission gear 209 after bending, so as to position the conductive steel shaft 208, and meanwhile, when the conductive sheet 207 is installed on the transmission gear 209, the clamping part protrudes out of the side wall of the transmission gear 209, and the protruding part contacts with the inner wall of the tubular structure of the photosensitive drum 205, so that electric communication is realized.

As shown in fig. 12, the conductive steel shaft 208 has a structure in which one end of the conductive steel shaft 208 is fixedly mounted on the apparatus frame 12 and the other end is cantilevered. When the process cartridge is mounted in the apparatus, the cantilever end of the conductive steel shaft 208 penetrates into the hollow region of the shaft portion of the transmission gear 209 of the photosensitive drum 205. The conductive steel shaft 208 passes through the transmission gear 209, so that not only can the conductive sheet 207 be connected to realize electrical communication, but also radial positioning effect can be provided for the photosensitive drum 205.

Optionally, the steel shaft of the process cartridge is located on a side cover, the side cover is used for connecting the end parts of each shaft/roller in the opc assembly, and the other end of the steel shaft passes through the side cover and extends out from the other side of the side cover;

Further, the conductive steel shaft 208 is mounted at one end of the frame 12, and is connected to the metal plate of the frame 12 through the Z-shaped grounding piece 2011. The zigzag grounding piece 2011 has elasticity, and one side of the grounding piece 2011 is screwed on the metal plate of the frame body 12, and the other side is elastically pressed on the end part of the conductive steel shaft 208. The grounding plate 2011 is in an elastic state and has elastic pretightening force when being just pressed against the end of the steel shaft.

Optionally, as shown in fig. 13, a driving member 2012 is further sleeved on the steel shaft. The driving member 2012 is provided with a plurality of right-angle driving claws 2013, and correspondingly, a driven protruding block 2014 is arranged on one side of the transmission gear 209 of the photosensitive drum 205, which is abutted against the driving member 2012, and the protruding block 2014 can receive power from the driving member 2012 after being matched with the right-angle driving claws 2013, so that the photosensitive drum 205 can be driven.

Further, a biasing member 206 is provided between the driver 2012 and the main body frame, and provides a biasing force to the driver 2012 always pressing against the transmission gear 209 to keep the driving pawl and the boss 2014 engaged in the axial direction for continuous stable transmission of driving force.

What has been described above is merely some embodiments of the present utility model. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the utility model.

Claims (10)

1. The processing box comprises a box body, a developing roller, a powder discharging knife and a powder discharging knife bracket, wherein the developing roller, the powder discharging knife and the powder discharging knife bracket are arranged in the box body, two ends of the developing roller are supported on the processing box to rotate around a shaft, and the developing roller adsorbs developer in the box body to form a developer layer on the outer peripheral surface;

The doctor blade is further arranged on the powder discharge blade bracket and is positioned at the upstream of the powder discharge blade in the rotation direction of the developing roller, and a second gap with a fixed width is kept between the doctor blade and the outer peripheral surface of the developing roller;

the width of the second gap is greater than the width of the first gap.

2. The process cartridge of claim 1, wherein said doctor blade holder includes a holder body and said doctor blade, said doctor blade protruding from said holder body and being connected to said holder body by a connecting rib, a gap being formed between said connecting ribs for passing toner.

3. The process cartridge of claim 1 or 2, wherein said doctor blade holder includes a first mounting surface providing a first positioning portion for defining a mounting position of said doctor blade and a second mounting surface providing a second positioning portion for defining a mounting position of said doctor blade holder within said cartridge;

the two ends of the powder outlet knife are fixedly connected to the inner wall of the box body.

4. A process cartridge according to claim 3, wherein a connecting groove is provided in the inner wall of the cartridge body, a first connecting member is disposed in the connecting groove, and second connecting members at both ends of the powder discharge blade are engaged with the first connecting member to fix the powder discharge blade.

5. The process cartridge of claim 4, wherein said first positioning portion includes at least two raised positioning posts, and said doctor blade has mounting holes corresponding to said positioning posts.

6. The process cartridge of claim 4, wherein said first coupling member is a nut and said second coupling member is a screw, said nut being enclosed in said coupling groove and being swingable with respect to said coupling groove without being separated from said coupling groove, and said screw being coupled to said nut through said blade when said blade is mounted, thereby fixing said blade.

7. The process cartridge of claim 6, wherein the nut is a metal nut, the coupling groove is formed of a plastic material having a lower melting point than the metal nut, and an inner wall of the coupling groove is melted when the metal nut is heated, thereby adjusting a gap between the metal nut and the inner wall of the coupling groove.

8. A process cartridge according to claim 3, wherein said blade has a wall thickness gradually increasing in a direction away from said developing roller surface.

9. The process cartridge of claim 1, wherein a side of said blade distal from said developer roller has a bend in a direction of fitting said blade holder such that a cross section of said blade is L-shaped.

10. A printer comprising the process cartridge according to any one of claims 1 to 9.