JP2013083771A - Developing device and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of forming a stable toner layer by absorbing a force for pushing up a developer regulating member by aggregated toner on a developing roller in a developing device to stabilize the abutting state between the developing roller and the developer regulating member, and to provide an image forming apparatus using the developing device.SOLUTION: A developing device 6 comprises a developing roller 62 for developing an electrostatic latent image formed on a photoreceptor drum 32 by supplying a developer to the photoreceptor drum 32 and a doctor blade 67 for regulating a layer thickness of a developer carried on the surface of the developing roller 62, wherein the doctor blade 67 has a configuration including a regulation part 68 for abutting on the developing roller 62 and a support blade 69 for supporting the regulation part and the regulation part 68 has a configuration in which the hardness of a front part 68b of the contact part is adjusted lower than the hardness of a contact part 68a with the developing roller 62 by bringing the regulation part 68 into surface contact with the developing roller 62.

Description

  The present invention relates to a developing device and an image forming apparatus using the same, and more particularly, to a developing device including a developing roller mounted on an image forming apparatus employing an electrophotographic system, and an image forming apparatus using the developing device.

  In an image forming apparatus that employs an electrophotographic system, a latent image formed on the surface of a photoconductor is developed by supplying toner as a developer component from a developing device and developing it. A toner image is formed, the toner image is further transferred onto a recording paper as a transfer medium, and the toner image transferred onto the recording paper is fixed to form a robust recording image.

In recent years, with the widespread use of color inkjet image forming apparatuses, image forming apparatuses using an electrophotographic system are also required to be reduced in size and price.
Under such circumstances, a non-magnetic one-component developing system that has a simple structure and can be miniaturized is often used as an electrophotographic developing apparatus.

Non-magnetic one-component development methods include a contact development method in which development is performed in contact with a latent image carrier, and a non-contact development method in which development is performed with a predetermined gap from the latent image carrier.
Both of them have similar structures of the developing device and have a compact feature, but the material of the developing roller may be different.

  In the contact development, in order to obtain uniform contact in the development area, the developing roller is composed of an elastic member such as conductive rubber. In particular, the configuration using a rigid body such as a photosensitive drum as the latent image carrier is effective from the viewpoint of preventing damage due to a failure in the contact state.

  When the developing roller is a rubber roller, as the doctor blade for forming the toner layer on the developing roller, a roller blade made of a rubber blade or a metal shaft, a blade made of a single metal plate, or the like is used. Among these, a blade made of a metal plate is widely used because it can be provided at low cost.

  On the other hand, in the case of non-contact development, since it is necessary to accurately maintain a gap with the photosensitive drum (latent image carrier), a roller or sleeve made of a rigid body such as metal is often used as the developing roller. This is because it is more effective than the rubber roller for improving the polishing accuracy of the surface and suppressing the eccentricity of the drive shaft and the surface. Moreover, since there is no contact, there is no fear of injury due to contact.

  In this case, several types of doctor blades can be used as in the case of the contact type described above, but a rubber blade is used from the viewpoint of contact stabilization at the toner layer regulating portion and prevention of scratches. There are many. As the rubber blade, the part that regulates the toner layer and the support part are all made of a single rubber material, or an elastic support member such as a metal plate and a toner layer in which the rubber material is arranged at the edge The thing which consists of a regulation part which regulates is known.

  Generally, as a method of contacting the developer regulating member with the developing roller, a so-called “edge contact method” in which the edge of the blade member (regulating member) is brought into contact with the developing roller 62 is used. There is a so-called “belly padding system” that makes contact.

  The edge contact method can form a sharp pressure distribution, but is sensitive to the shape of the end face of the regulating member and the accuracy of the contact position, and has a problem in the stability of layer formation.

  Therefore, as a method for solving these problems in the edge contact method, the rubber material of the contact portion of the blade member is changed (see Patent Document 1), or the contact portion of the blade member is in stable contact. As described above, there has been proposed one in which the rubber hardness or shape of the attachment portion of the contact portion is changed (see Patent Document 2).

  On the other hand, in the case of the belly contact method, it is easy to set the contact state between the blade member and the developing roller relatively stably, but the pressing pressure is lower than that in the edge contact method, and when a small particle size toner is used. The toner layer may be difficult to form.

  Therefore, in order to solve these problems, there have been proposed ones in which the hardness, protrusion amount, load, etc. of the blade member are adjusted as appropriate, and the shape of the rubber member of the blade contact portion is formed in a convex shape (patent) See reference 3.)

These proposals are aimed at equalizing the contact state of the contact portion between the developing roller 62 and the blade member (regulating member) 968 of the doctor blade 967 as shown in FIGS. 22 (a) and 22 (b), for example. In the initial stage of use, it is effective in achieving uniform toner layer formation and stabilization.
Reference numeral 969 denotes a support blade that holds the blade member 968, and T1 denotes a good toner layer formation state.
FIG. 22A is an explanatory view showing a toner layer formation state at the initial stage of toner use by a conventional doctor blade, and FIG. 22B is a front view as seen from an arrow A in FIG.

  In addition, when a metallic developing roller is used, the edge contact method is initially good, but the edge portion is liable to be damaged due to use over time, thereby causing unevenness of the toner layer. Tend. On the other hand, in the case of the abdominal contact method, damage deterioration of the blade member due to rubbing against the metal roller is not so great, which is advantageous for stabilization in long term use.

However, in the technique according to Patent Document 3, toner layer non-uniformity may occur for the following reason. In other words, due to the use of the toner over time, the external additive applied to the toner surface is detached or buried due to stress due to toner layer regulation or toner stirring, and the fluidity of the toner is lowered. Hereinafter, the toner cannot smoothly enter the “blade nip”. Accordingly, as shown in FIGS. 23A and 23B, the action of the toner pushing up the blade member 968 in front of the blade nip becomes stronger, and the blade contact state becomes uneven (unstable state). As a result, it was found that the toner slips through, resulting in a non-uniform streaky toner layer formation state T2.
FIG. 23A is an explanatory view showing a toner layer forming state when the toner is deteriorated by a conventional doctor blade, and FIG. 23B is a front view as seen from arrow B in FIG.

  If the rubber material of the blade member 968 is softened against the above-mentioned conventional problems, the pushing-up action by the aggregated toner before the blade nip can be absorbed, but there may be cases where the desired pressure distribution at the blade nip cannot be obtained. The toner layer formation condition is deviated, and this causes a problem in the toner layer formation when the small particle size toner is used, which is one of the problems described above.

  In view of this, with respect to the control of the toner flow before the blade nip, as a conventional technique, for example, a rubber material of the blade member before the blade nip is cut to form a smooth entry state (Patent Document 4). See).

  As another conventional technique, there is disclosed a technique in which a recessed portion is provided in a blade member before the blade nip so that a coherent toner enters the recessed portion and circulates to obtain a stable toner intrusion state ( (See Patent Document 5).

JP 2010-66332 A JP 2000-10402 A JP 2000-112230 A Japanese Patent Laid-Open No. 07-64391 Japanese Patent Laid-Open No. 02-25865

  However, the technique disclosed in Patent Document 4 cannot obtain an effect of stabilizing the contact state of the blade nip while absorbing the push-up force caused by the aggregated toner.

  Further, in the technique according to Patent Document 5, if toner aggregation progresses, toner circulation in the recess may not function well. Furthermore, it is difficult to stabilize the contact state at the blade nip while absorbing fluctuations in toner push-up force associated with changes in toner fluidity due to use over time.

  In other words, in order to solve the above-mentioned problems, the pressure distribution of the blade nip is maintained in a desired state, and the fluctuation of the push-up force from the toner entering the blade nip due to the change in the toner characteristics due to use over time is absorbed. There is a need to.

  The present invention has been made in view of the above-described conventional problems, and absorbs the force that pushes up the developer regulating member by the aggregated toner on the developing roller in the developing device, so that the developing roller and the developer regulating member It is an object of the present invention to provide a developing device capable of forming a stable toner layer by making the contact state constant and an image forming apparatus using the developing device.

  The developing device and the image forming apparatus using the same according to the present invention for solving the above-described problems are as follows.

  The present invention is provided in an electrophotographic image forming apparatus, and a developer (particularly, a non-magnetic one-component developer, for example, toner) is supplied to a photoconductor provided in the image forming apparatus so that the photoconductor is provided on the photoconductor. A developing device comprising: a developing roller for developing the electrostatic latent image formed on the surface; and a developer regulating member (for example, a doctor blade) that regulates the layer thickness of the developer carried on the surface of the developing roller. The developer regulating member includes: an elastic member (for example, an elastic blade) that contacts the developing roller; and a support member (for example, a support blade) that supports the elastic member, and the elastic member and the The surface of the developing roller is brought into contact with the developing roller, and the elastic member is configured such that the hardness of the region near the upstream side in the rotation direction of the developing roller is higher than the hardness of the contacting portion (contacting nip portion) with the developing roller. Low It is characterized in that the so that.

  In the present invention, it is preferable that a part of a region near the upstream side in the rotation direction of the developing roller is cut away from the contact portion as a configuration of the elastic member.

  In the present invention, it is preferable that a plurality of cut portions (notches) of the elastic member are provided so as to overlap in the thickness direction of the elastic member.

  According to the present invention, as a configuration of the cut portion of the elastic member, an opening is formed on the upstream side of the elastic member in the rotation direction of the developing roller, and the elastic member is formed along the rotation direction of the developing roller. The development of the contact portion between the elastic body and the developing roller is defined as θ1 which is an angle formed by the surface on the developing roller side inside the cut portion of the member and the surface of the elastic member facing the developing roller. When θ2 is an angle formed by a tangent line of the developing roller passing through an upstream end portion (contact nip end position) of the roller and a surface of the elastic member facing the developing roller, “θ1> θ2” It is preferable to satisfy the conditions.

  Moreover, it is preferable that this invention is comprised so that the excised part of the said elastic member may be penetrated in the thickness direction of the said elastic member.

  Further, in the present invention, as a configuration of the elastic member, a part of a region near the upstream side in the rotation direction of the developing roller with respect to the contact portion of the elastic member with the developing roller may be formed in a foam shape. preferable.

  In the present invention, the support member is preferably configured using a leaf spring member.

  In the present invention, the supporting member is configured such that one end is a fixed end fixed to the developing device main body side, the other end is a free end, the elastic member is held on the free end side, and the free end Preferably, the elastic member is held at a position extending beyond the contact portion between the elastic member and the developing roller to the side opposite to the fixed end.

  In the present invention, it is preferable that the developing roller is configured using a metal member.

  In addition, the present invention includes a photoconductor on which an electrostatic latent image is formed, and a developing roller for supplying a developer to the photoconductor to develop the electrostatic latent image formed on the photoconductor. In the image forming apparatus for forming an image by an electrophotographic method, the developing device includes a developer regulating member that regulates a layer thickness of the developer carried on the surface of the developing roller. A developing device according to any one of claims 1 to 9 is provided.

  According to the developing device of the present invention, an electrostatic latent image formed on an electrophotographic image forming apparatus by supplying a developer (for example, toner) to the photoconductor provided in the image forming apparatus. In a developing device including a developing roller for developing an image and a developer regulating member that regulates a layer thickness of the developer carried on the surface of the developing roller, the developer regulating member is configured as the developing device. An elastic member that contacts the roller; and a support member that supports the elastic member. The elastic member and the developing roller are in contact with each other by surface contact, and the elastic member is configured to contact the developing roller. By setting the hardness of the region near the upstream side in the rotation direction of the developing roller to be lower than the hardness of the portion, the developer regulating member may be pushed by agglomeration of deteriorated toner that causes a decrease in toner fluidity due to use over time. Even if the bending action occurs, it is possible to maintain the pressure distribution of the contact portion in a desired state while absorbing the push-up force due to the aggregated toner due to the deformation of the elastic member in front of the contact portion. A stable toner layer can be formed.

  That is, the developer is likely to cause toner aggregation in front of the contact portion of the developer regulating member due to a decrease in toner fluidity due to use over time. This action makes it difficult for the toner to enter the contact portion between the developer regulating member and the developing roller, causing the aggregated toner to push up the developer regulating member, and the contact between the developer regulating member and the developing roller. As a result, the contact state becomes non-uniform, and the toner slips through, resulting in a non-uniform state of the toner layer.

  Therefore, by using a soft elastic member (for example, a blade rubber material) at the portion that comes into contact with the developing roller, it is possible to absorb the pushing-up action by the aggregated toner before the contact portion. When a pressing force (blade load) is applied to the member, the change in the elastic member increases, the nip width widens, and the contact pressure decreases, so the desired pressure distribution cannot be obtained at the contact portion (contact nip portion). .

  In addition, in the case of non-contact development, particularly when using a toner flying action by a DC electric field that does not use an alternating voltage, the developer regulating member pressing (blade pressing) at the time of toner layer regulation is not excessively increased in order to improve toner flying performance. However, since the blade pressing is small, there are cases where the influence of the aggregated toner on the blade pressing is likely to occur. By using the present invention, it is possible to stabilize the blade pressing, which is more preferable when non-contact development is used.

  Further, according to the present invention, as the configuration of the elastic member, a part of the region near the upstream side in the rotation direction of the developing roller is cut away from the contact portion, so that the contact portion and the contact portion can be contacted with a simple configuration. The substantial hardness of the front portion of the contact portion can be changed, and the hardness of the elastic member suitable for forming the toner layer and the hardness suitable for absorbing the pushing force of the aggregated toner can be set as appropriate.

  Further, according to the present invention, when the cut portion of the elastic member is provided at a plurality of positions so as to overlap in the thickness direction of the elastic member, the substantial hardness before the contact portion or when pressed against the toner The degree of deformation can be arbitrarily adjusted. As a result, it is possible to suppress pressure fluctuation at the contact portion (contact nip portion) and to obtain a stable toner approach state to the contact portion, thereby enabling more stable toner layer formation.

  Further, according to the present invention, as a configuration of the cut portion of the elastic member, an opening is formed on the upstream side of the elastic member in the rotation direction of the developing roller, and the elastic member is formed along the rotation direction of the developing roller, The angle formed by the surface on the developing roller side inside the cut portion of the elastic member and the surface of the elastic member facing the developing roller is defined as θ1, and the contact portion between the elastic body and the developing roller is When the angle formed by the tangent line of the developing roller passing through the upstream end portion (position of the contact nip portion end) of the developing roller and the surface of the elastic member facing the developing roller is θ2, “θ1 By satisfying the condition “> θ2”, when the toner enters the cut portion, a part of the pushing-up force of the entering toner acts in a direction to push down a part of the elastic member below the cut portion. As a result, the force that the aggregated toner pushes up the entire elastic member can be relaxed, and a more stable toner layer can be formed.

  According to the present invention, the cut portion of the elastic member is configured to penetrate in the thickness direction of the elastic member, so that the toner that has entered the cut portion is opposite to the contact portion of the elastic member. Since the toner is discharged from the side, the pressure of the aggregated toner can be suppressed to a certain level, and a more stable toner layer can be formed.

  Further, according to the present invention, as a configuration of the elastic member, a part of a region near the upstream side in the rotation direction of the developing roller with respect to the contact portion of the elastic member with the developing roller is formed in a foam shape. Thus, it is possible to realize an elastic member having a portion with different hardness with a simple structure.

  In addition, according to the present invention, since the supporting member is configured by using a leaf spring member, the elastic member can be stably pressed against the developing roller, so that a stable toner layer can be formed over a long period of time. it can.

  Further, according to the present invention, as the structure of the support member, one end is a fixed end fixed to the developing device main body side, the other end is a free end, the elastic member is held on the free end side, By configuring the free end to hold the elastic member at a position extending beyond the contact portion between the elastic member and the developing roller to the opposite side of the fixed end, that is, free By disposing the end so as to straddle the contact portion between the elastic member and the developing roller, the pressure contact force of the contact portion can be controlled to be constant even if the elastic member is slightly misaligned. .

  In addition, according to the present invention, since the developing roller is configured by using a metal member, the contact state of the developer regulating member (elastic member) can be kept stable, so that the image in the non-contact developing system can be maintained. Stabilization can be further improved.

  Specifically, when performing non-contact development, it is important to accurately maintain the distance (development gap) between the photoconductor and the development roller, and using a metal development roller is more preferable for stabilizing the development gap. is there. However, in the case of a metal roller, the pressure by the agglomerated toner can hardly be absorbed on the roller side, so that the blade is easily pushed up. Therefore, by adopting the configuration of the developer regulating member of the present invention, the blade contact state can be stabilized.

  In addition, according to the image forming apparatus of the present invention, a photosensitive member on which an electrostatic latent image is formed is provided, and a developer is supplied to the photosensitive member to develop the electrostatic latent image formed on the photosensitive member. In an image forming apparatus, comprising: a developing roller including: a developing roller; and a developer regulating member that regulates a layer thickness of the developer carried on the surface of the developing roller. Since the developing device according to any one of claims 1 to 9 is provided as the developing device, the pressure distribution of the contact portion (contact nip portion) between the developer regulating member and the developing roller is provided. Can be kept constant in a desired state, so that a stable toner layer can be formed.

1 is an explanatory diagram illustrating a schematic configuration of an image forming apparatus including a developing device according to an embodiment of the present invention. It is explanatory drawing which shows the structure of the developing device which concerns on this embodiment. (A) is explanatory drawing which shows the structure of Example 1 of the doctor blade of this embodiment, (b) is explanatory drawing which shows the effect | action of the said doctor blade. (A) Explanatory drawing which shows the effect | action of the conventional doctor blade, (b) is explanatory drawing which shows the structure of the notch part of the said doctor blade, (c) is a blade pressure in the contact nip part of Example 1 and a prior art example. It is a graph which shows. It is explanatory drawing which shows the modification 1 of the doctor blade of Example 1. FIG. It is explanatory drawing which shows the modification 2 of the doctor blade of Example 1. FIG. It is explanatory drawing which shows the modification 3 of the doctor blade of Example 1. FIG. It is explanatory drawing which shows the structure of Example 2 of the doctor blade of this embodiment. It is explanatory drawing which shows the modification 1 of the doctor blade of Example 2. FIG. It is explanatory drawing which shows the modification 2 of the doctor blade of Example 2. FIG. (A) is explanatory drawing which shows the structure of Example 3 of the doctor blade of this embodiment, (b) is explanatory drawing which shows the effect | action of the said doctor blade. It is explanatory drawing which shows the modification of the doctor blade of Example 3. FIG. It is explanatory drawing which shows the structure of Example 4 of the doctor blade of this embodiment. It is explanatory drawing which shows the modification 1 of the doctor blade of Example 4. FIG. It is explanatory drawing which shows the modification 2 of the doctor blade of Example 4. FIG. It is explanatory drawing which shows the structure of Example 5 of the doctor blade of this embodiment. It is explanatory drawing which shows the structure of Example 6 of the doctor blade of this embodiment. It is explanatory drawing which shows the modification which reversed the protrusion direction of the doctor blade of Example 6. FIG. It is explanatory drawing which shows the structure of Example 7 of the doctor blade of this embodiment. It is explanatory drawing which shows the modification which made the protrusion direction of the doctor blade of Example 7 reverse. 10 is an explanatory view showing a comparative example of a doctor blade of Example 7. FIG. (A) is explanatory drawing which shows the toner layer formation state in the toner use initial stage by the conventional doctor blade, (b) is a front view by A arrow of (a). (A) is explanatory drawing which shows the toner layer formation state at the time of the toner deterioration by the conventional doctor blade, (b) is a front view by B arrow of (a).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for carrying out a developing device of the present invention and an image forming apparatus including the developing device will be described below with reference to the drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is an example of an embodiment of the invention, and is an explanatory diagram illustrating a schematic configuration of an image forming apparatus including a developing device according to an embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment includes a photosensitive drum (photosensitive member) 32 on which an electrostatic latent image is formed, and supplies a developer to the photosensitive drum 32 to perform photosensitive. A developing roller 62 for developing the electrostatic latent image formed on the body drum 32, and a doctor blade (developer regulating member) 67 for regulating the layer thickness of the developer carried on the surface of the developing roller (FIG. 2). In the image forming apparatus 1 that forms an image by an electrophotographic method, the developing device 6 having the characteristic configuration of the developing device is employed. .

  First, the overall configuration of an image forming apparatus 1 including a developing device 6 according to an embodiment of the present invention will be described with reference to FIG.

  The image forming apparatus 1 according to the present embodiment has a copier mode (copying mode), a printer mode, and a FAX mode as print modes, an operation input from an operation unit (not shown), and an external host device such as a personal computer. A print mode corresponding to the reception of the print job from is selected by the control unit described later.

  As shown in FIG. 1, the image forming apparatus 1 is roughly divided into a document reading unit 10, a paper feeding unit 20, a printing unit 30, and a paper discharge unit 40, and the document reading unit 10 is disposed above the paper feeding unit 20. The paper discharge unit 40 is disposed at an intermediate position between the document reading unit 10 and the paper supply unit 20.

Hereinafter, the copier mode will be described from the above processing modes.
After the user places an original on the platen glass 11 of the original reading unit (scanner unit) 10, the paper (recording paper) is placed on the paper supply cassette 21 of the paper supply unit 20 or the manual feed tray 23 provided on the side of the apparatus. The copy operation is started when the start key on the operation panel is operated after the condition input key (number of prints / printing magnification, etc.) is input on the operation panel (not shown) which is mounted and further disposed on the front surface of the apparatus. The

  When the start key is operated, a main drive motor (not shown) starts and each drive gear rotates. Thereafter, the paper feed roller 22 or 22a rotates to feed (feed) the paper into the apparatus, and the fed paper reaches the registration roller 31 (roller pair) and is captured.

  The registration roller 31 temporarily stops the paper so as to synchronize with the leading edge (image formation start portion) of the image formed on the photosensitive drum 32, and the leading edge of the paper is uniformly pressed against the registration roller 31. Thus, the leading edge position of the paper is corrected.

  On the other hand, in the document reading unit 10, the copy lamp (light source) 12a is turned on, and the copy lamp unit 12 moves in the direction of arrow C to start exposure. Irradiation light applied to the original by the copy lamp 12a becomes reflected light (reflected light from the original) including image information of the original, and the reflected light is transmitted from the first mirror 12b provided in the copy lamp unit 12 to the second light. Reading is performed by inputting to the CCD 16 from the mirror 13, the third mirror 14, and the optical lens 15.

  The image information read in this way is converted into an electrical signal by a CCD circuit (not shown), and the image information signal is subjected to image processing under a set condition, and the laser scanner unit. 33 as print data.

  On the other hand, a part of the peripheral surface of the photosensitive drum 32 is charged to a predetermined charging potential over the entire axial direction by the charging unit (charging means) 34, and the entire peripheral surface is predetermined by rotating the photosensitive drum 32. The negative charging potential is charged. The surface of the charged photoconductive drum 32 moves to the next process as the photoconductive drum 32 rotates.

  Next, in the laser scanner unit 33 (exposure means), a photosensitive member while the laser beam emitted from the semiconductor laser is deflected by a polygon mirror (rotating polygon mirror) having a plurality of reflecting surfaces in the rotation direction and various optical systems. The drum 32 is irradiated. Thereby, the laser beam is scanned on the photosensitive drum 32 charged by the charging unit 34, and an electrostatic latent image is formed on the photosensitive drum 32.

  Thereafter, toner (an example of a developer) in the developing tank 61 is supplied onto the surface of the rotating photosensitive drum 32 by the developing roller 62 applied with a negative DC potential in the developing tank 61 provided in the developing device 6. The electrostatic latent image is visualized (developed) by this toner in accordance with the potential gap on the photosensitive drum 32.

  In addition, paper (recording paper) to be imaged is conveyed in the direction of the photosensitive drum 32 by the registration roller 31 in time, and the toner on the photosensitive drum 32 is transferred by a transfer unit (corona charger (transfer means)) 36. Is transferred to the paper. The toner remaining on the photosensitive drum 32 is scraped off by the cleaning blade 37 a of the drum unit and collected by the cleaner unit 37.

  The surface of the photosensitive drum 32 from which the toner has been removed by the cleaning blade 37 a is neutralized as necessary by a neutralization device (static neutralization means) 39 while moving to the charging unit 34.

  On the other hand, the paper on which the toner has been transferred passes between the heating roller 38a and the pressure roller 38b of the fixing device 38 (fixing process), and heat and pressure are applied, so that the unfixed toner on the paper is transferred to the paper. Then, the sheet is melted and fixed by the sheet discharge roller 41 and discharged to the sheet discharge tray 42. The heating roller 38a is heated by a heater 38c provided therein.

  In addition, when it is detected by a predetermined sensor that a document is placed on the document tray 19 provided in the document reading unit 10, the paper feed roller 51 rotates when a predetermined start key operation is performed. Then, the document placed on the document tray 19 is sent into the document reading unit 10 and is transported through a predetermined transport path Rt1.

  A registration roller 53 is provided on the conveyance path Rt1, and the document is captured by the registration roller 53, and the leading end of the document is positioned, and then conveyed to the document reading position at a predetermined timing.

Then, the document being conveyed is exposed while the copy lamp unit 12 is stopped at a predetermined stop position (document reading position). The process of reading the document image by the reflected light from the document obtained by this exposure is as described above.
The document whose image has been read in this manner is discharged to the document discharge unit 18.

Next, the characteristic developing device 6 according to the present embodiment will be described with reference to the drawings.
FIG. 2 is an explanatory diagram showing a schematic configuration of the developing device according to the present embodiment.

  As shown in FIG. 2, the developing device 6 according to the present embodiment supplies a developer to the photosensitive drum 32 provided in the image forming apparatus 1 to develop an electrostatic latent image formed on the photosensitive drum 32. Development roller 62, developer tank 61 containing developer, stirring and conveying members 63, 64 and 65 for stirring and conveying developer 60 in developer tank 61, and development carried on the surface of developing roller 62 And a doctor blade (developer regulating member) 67 for regulating the layer thickness of the developer. Each rotates counterclockwise as indicated by an arrow.

  The developing device 6 includes a restricting portion (elastic member) 68 that contacts the developing roller 62 and a support blade (supporting member) 69 that supports the restricting portion 68 as a configuration of the doctor blade 67. This restricting portion 68 is brought into contact with the developing roller 62 by surface contact, and is an area in the vicinity of the upstream side in the rotation direction of the developing roller 62 (hereinafter referred to as the hardness of the contacting portion (contacting nip portion) 68a with the developing roller 62 (hereinafter referred to as the following) This is referred to as “the front portion of the contact portion.” The hardness of 68b is configured to be low.

The developing roller 62 is an aluminum developing roller that is rotatably provided in the developing tank.
The developing roller 62 faces the photosensitive drum 32, is arranged so that its axis is parallel to the rotational axis of the photosensitive drum 32, and is supported by the frame portion of the developing tank 61 body.

  As the developer carried on the developing roller 62, toner that is a non-magnetic one-component developer is used.

  In the developing tank 61, a toner supply roller 66 provided upstream of the developing roller 62 in the toner transport direction attracts the toner to the surface and supplies a certain amount of toner onto the developing roller.

  Above the developing roller 62, a so-called doctor blade 67, a developer regulating member for forming a certain amount of toner layer on the developing roller 62, is provided. A restricting portion 68 made of urethane rubber integrated with the support blade 69 is provided at the tip of the support blade 69 constituting the doctor blade 67, and the support blade 69 is sandwiched between the fixed metal plates 71 and 72 at the other end side. In this state, the developer tank 61 is fixed to the main body by screws 73.

  The support blade 69 is a thin metal plate having a spring property, and the spring portion presses the restricting portion 68 onto the developing roller 62 with a constant pressure. As a result, a toner layer having a constant charge is carried on the developing roller 62.

  The toner having these charges is supplied from the developing roller 62 to the photosensitive drum 32 according to the potential difference between the developing roller 62 and the photosensitive drum 32 to develop the electrostatic latent image to form a toner image.

  The developing tank 61 is a container member made of, for example, hard synthetic resin and having an approximately rectangular parallelepiped appearance. In the developing tank 61, the first stirring / transporting member 65 and the second stirring / transporting member 63 mainly have a role of stirring and transporting the toner in the rotation direction. Both members have thin resinous, for example, PET wings provided around the rotating shaft.

  In addition, a third agitation transport member 64 is disposed between the first agitation transport member 65 and the second agitation transport member 63. The third stirring and conveying member 64 is a screw-like rotating member made of, for example, a hard synthetic resin, and mainly has a role of stirring and conveying toner in the axial direction.

An intermediate wall member 80 is provided between the second stirring and conveying member 63 and the toner supply roller 66. The intermediate wall member 80 is a flat plate member made of, for example, synthetic resin, and is provided so as to extend in the longitudinal direction of the developing tank 61 and rise from the bottom of the developing tank 61.
An opening hole 81 is formed in the central portion of the intermediate wall member 80, and a developer flow from the second stirring / conveying member 63 toward the toner supply roller 66 is formed in the developing tank 61.

  The toner supply roller 66 is provided with a cylindrical porous elastic member such as foamed urethane around a cored bar. The toner supply roller 66 rubs the developing roller 62 while adsorbing toner in the hole. It also serves to supply toner to the developing roller 62 and to clean the excess toner layer remaining on the developing roller 62 after development.

Example 1
Next, a first example of a doctor blade configuration characteristic of the present embodiment will be described with reference to the drawings.
3A is an explanatory view showing the configuration of Example 1 of the doctor blade of the present embodiment, FIG. 3B is an explanatory view showing the action of the doctor blade, and FIG. 4A shows the action of the conventional doctor blade. Explanatory drawing, (b) is explanatory drawing which shows the structure of the notch part of the said doctor blade, (c) is a graph which shows the blade pressure in the contact nip part of Example 1 and a prior art example, FIG. FIG. 6 is an explanatory view showing a doctor blade modification 2 of the first embodiment, and FIG. 7 is an explanatory view showing a doctor blade modification 3 of the first embodiment.

  FIG. 3A shows an initial state in which toner deterioration has not progressed so much. FIG. 3B shows that toner deterioration has progressed and toner aggregation has pushed the blade up before the contact nip between the blade and the developing roller. The state which has given the action is shown.

  As shown in FIGS. 3A and 3B, the doctor blade 67 according to the first embodiment includes a restricting portion 68 that contacts the developing roller 62 and a support blade 69 that supports the restricting portion 68.

The restricting portion 68 is brought into contact with the developing roller 62 by surface contact and is made of urethane rubber. In addition, silicon rubber or the like can be used.
Further, as shown in FIGS. 3A and 3B, the restricting portion 68 is closer to the upstream side in the rotation direction of the developing roller 62 than the hardness of the contacting portion (contacting nip portion) 68a with the developing roller 62. The contact portion front portion 68b is configured to have a low hardness.

  Specifically, the overall hardness of the restricting portion 68 is preferably 65 ° to 85 ° in terms of JIS-A hardness, and is set to 75 ° to 80 ° in this embodiment. The thickness t1 of the restricting portion 68 is preferably 0.5 to 3 mm, and is 2 mm in this embodiment. Further, the length L1 of the restricting portion 68 in the direction along the rotation direction of the developing roller 62 is 8 mm.

  Further, in the first embodiment, a notch portion 68c is formed in a part of the region of the regulating portion 68 near the upstream side in the rotation direction of the developing roller 62 with respect to the contact portion 68a. An opening 68d of the notch 68c is formed on the upstream side of the regulating portion 68 in the rotation direction of the developing roller 62. The notch 68c has t2 of 1 mm in the thickness direction and L2 of 3 mm in the width direction, and the end portion of the notch 68c is formed in an arc shape in cross section.

  Further, the central portion 68CL of the restricting portion 68 is set to the center 68a1 of the contact portion (contact nip) 68a of the developing roller 62 and the restricting portion 68 so that the notch portion 68c does not reach the range of the contact portion 68a. Is formed.

  With such a configuration, in the restricting portion 68, the substantial hardness of the front portion 68b of the contact portion where the notch portion 68c is present is reduced. In addition, the shape of the notch 68c is not limited to this.

Next, the support blade 69 will be described.
The support blade 69 is formed using a phosphor bronze plate as a material. Other materials can be used as long as they have a spring property such as a stainless steel plate or a beryllium copper plate and can withstand the molding temperature of the rubber material.

  The thickness t3 of the support blade 69 is preferably 0.05 to 0.25 mm. In this embodiment, a thickness t3 of 0.12 mm was used. The length of the support blade 69 (the length along the rotation direction of the developing roller 62) is 30 mm, and the distance from the fixed side of the developing device 6 main body side to the blade nip, the so-called free length is 17 mm. Yes.

  The restricting portion 68 having the above structure can be obtained by setting the support blade 69 in a mold, melting and injecting a rubber material into the mold, and integrally molding. Alternatively, the regulating portion 68 and the support blade 69 may be fixed with an adhesive or an adhesive tape.

  As shown in FIGS. 3A and 3B, the restricting portion 68 configured as described above is brought into contact with the developing roller 62 to restrict the developer layer. The pressing force applied to the restricting portion 68 was set to 30 gf / cm per 1 cm.

As a comparative example of Example 1, as shown in FIG. 4A, a contact state similar to that of the doctor blade 67 of Example 1 was set using a doctor blade 967 of the prior art.
The structure of the restriction part 968 of the conventional doctor blade 967 is the same except that there is no notch in the rubber member.

  The developing roller 62 used in Example 1 and the comparative example has a diameter of 16 mm and is made of an aluminum sleeve. The surface of the sleeve has an average roughness Ra of 0.3 to 0.5 μm and is blasted with glass beads. The rotational peripheral speed of the sleeve was 145 mm / s.

  The developer used in Example 1 and the comparative example is a non-magnetic one-component toner having a polyester resin as a main component, and is prepared by a pulverization method with an average particle size of 8 μm.

  Using the doctor blades 67 and 967 of Example 1 and Comparative Example described above, the developer layer formation state and the image forming performance were confirmed.

In both Example 1 and Comparative Example, an idling aging test was performed with the developer adhesion amount per unit area on the initial sleeve being about 0.6 mg / cm ² and the charge amount being about −7 μC / g.

  In the initial state, both toner layers were uniformly formed, but after about 2 hours, streaky unevenness of the toner layer was observed in the comparative example. The streaky unevenness includes a locally thick toner layer due to toner slipping from the abutting portion 968a of the restricting portion 968 and a slightly thinner toner layer on both sides. It is in a state of appearing alternately.

  When the restricting portion 968 was removed and the abutting portion 968a was observed, portions where the toner slipped locally were scattered. In order to confirm the image formation state at this time, when an image was output with a machine modified from a commercially available MFP machine (Sharp AR-C262S), image unevenness corresponding to the toner layer streaks on the developing roller 62 was observed. It was.

  On the other hand, in the doctor blade 67 of Example 1 to which the present invention was applied, a uniform toner layer was formed even after 2 hours, and generation of toner layer streaks and accompanying image defects were not observed.

  When the restricting portion 68 is removed and the contact portion 68a is observed, the toner passing state is uniform, and the blade push-up action by the aggregated toner is caused by the notch portion 68c of the contact portion front portion 68b, which is a characteristic configuration of the present invention. The absorption effect of was observed.

  Therefore, according to the doctor blade 67 of the first embodiment, as shown in FIG. 4B, the notch portion 68c of the front portion 68b of the contact portion is crushed so that the blade pushing-up action by the aggregated toner can be absorbed. Therefore, as shown in FIG. 4C, the blade pressure at the contact portion 68a can be increased as compared with the conventional doctor blade 167, so that generation of toner layer streaks and associated image defects can be suppressed. it can.

  Note that the notch structure of the restricting portion 68 is not limited to the structure shown in FIGS. 3A, 3B, and 4B, but as a modified example 1, as shown in FIG. The portion 68c1 has a U-shaped cross section, or as a modified example 2, as shown in FIG. 6, has a wedge-shaped cross section, or as a modified example 3, as shown in FIG. You may comprise with the hollow body which has the hollow part 68c3, and the same effect is acquired, respectively.

(Example 2)
Next, a second example of the doctor blade configuration characteristic of this embodiment will be described with reference to the drawings.
FIG. 8 is an explanatory diagram showing a configuration of Example 2 of the doctor blade of the present embodiment, FIG. 9 is an explanatory diagram showing Modification 1 of the doctor blade of Example 2, and FIG. 10 is a modification of the doctor blade of Example 2. FIG.

  As shown in FIG. 8, the doctor blade 167 according to the second embodiment includes a restriction portion (elastic member) 168 that contacts the developing roller 62 and a support blade (support member) 169 that supports the restriction portion 168. .

  The basic configurations of the restriction portion 168 and the support blade 169 in the second embodiment are the same as those of the restriction portion 68 and the support blade 69 in the first embodiment.

  In the second embodiment, a plurality of cutout portions 168 c 1 similar to the cutout portions 68 c of the first embodiment are provided on the front portion 168 b of the restriction portion 168 so as to overlap in the thickness direction of the restriction portion 168.

  According to the doctor blade 167 of the second embodiment, since the plurality of cutout portions 168c1 are crushed, the blade push-up action by the aggregated toner can be absorbed more, so that the toner layer is similar to the doctor blade 67 of the first embodiment. Generation of streaks and accompanying image defects can be suppressed.

  In addition, as a first modification of the second embodiment, as shown in FIG. 9, a plurality of notch portions 168 c 2 having a wedge-shaped cross section are provided so as to overlap in the thickness direction of the restriction portion 168. As shown in FIG. 10, a plurality of notches 168 c 31, 168 c 32, 168 c 33 having different cross-sectional shapes may be provided in combination so as to overlap in the thickness direction of the restricting portion 168.

  By adopting such a configuration, it is possible to make the deformed state of the contact portion front portion 168b of the restricting portion 168 more desirable.

(Example 3)
Next, a third example of the doctor blade configuration characteristic of the present embodiment will be described with reference to the drawings.
FIG. 11A is an explanatory view showing the configuration of Example 3 of the doctor blade of the present embodiment, FIG. 11B is an explanatory view showing the operation of the doctor blade, and FIG. 12 is a modified example of the doctor blade of Example 3. It is explanatory drawing shown.

  As illustrated in FIG. 11A, the doctor blade 267 of the third embodiment includes a restriction portion (elastic member) 268 that contacts the developing roller 62 and a support blade (support member) 269 that supports the restriction portion 268. I have.

  The basic configurations of the restriction portion 268 and the support blade 269 in the third embodiment are the same as those of the restriction portion 68 and the support blade 69 in the first embodiment.

  In the third embodiment, a notch 268 c is formed in the restricting portion 268 along the rotation direction of the developing roller 62. An opening 268d of the notch 268c is formed on the upstream side of the regulating portion 268 in the rotation direction of the developing roller 62.

  The notch 268c is defined by the angle of the surface 268c1 on the developing roller 62 side inside the notch 268c of the restricting portion 268 and the surface 268e of the restricting portion 268 facing the developing roller 62 in the restricting portion 268 as θ1. The tangent 268L1 of the developing roller 62 passing through the end portion (contact nip end position) 268a1 of the contact portion 268a between the restricting portion 268 and the developing roller 62 in the rotation direction upstream of the developing roller 62 and the developing roller 62 of the restricting portion 268. When the angle formed by the surface 268e facing the surface θ2 is θ2, (θ1> θ2) is established.

Here, the effect by the doctor blade 167 of Example 3 is demonstrated.
As shown in FIG. 11B, when the toner conveyed by the rotation of the developing roller 62 is regulated by the regulating unit 268, a part of the regulated toner is transferred from the opening 268d into the notch 268c. Enters.

  When the toner enters the notch 268c from the opening 268d, the force generated by the toner entering acts as a force that pushes up the restricting portion 268. Part of the push-up force generated by the toner entering acts on the lower surface 268c1 of the notch 268c and acts in a direction (F direction) to push down a part of the restricting part 268.

  As a result, the force that pushes up the entire restricting portion 268 by the aggregated toner can be relaxed. In other words, the pressure absorbing action due to the deformation of the notch 268c acts on the upstream side before the abutting part 268a, and the action of pressurizing the vicinity of the abutting part 268a is given by the toner that has entered the notch 268c. A stable toner layer can be formed.

  As a modification of the third embodiment, as shown in FIG. 12, a notch 268c11 is formed inside the restricting portion 268, and the opening of the notch 268c11 is formed upstream of the restricting portion 268 in the rotation direction of the developing roller 62. The portion 268d1 may be formed, and the cutout portion 268c11 may have an opening 268d2 penetrating upward in the thickness direction of the restricting portion 268.

  With this configuration, it is possible to prevent the aggregated toner from being press-fitted into the notch 268c11 and gradually prevent the pressure absorbing function from being sufficiently exerted, and it is possible to form a stable toner layer for a longer period of time. It becomes.

Example 4
Next, a fourth example of the doctor blade configuration characteristic of the present embodiment will be described with reference to the drawings.
FIG. 13 is an explanatory view showing a configuration of Example 4 of the doctor blade of the present embodiment, FIG. 14 is an explanatory view showing Modification 1 of the doctor blade of Example 4, and FIG. 15 is a modification of the doctor blade of Example 4. FIG.

  As shown in FIG. 13, the doctor blade 367 according to the fourth exemplary embodiment includes a restriction portion (elastic member) 368 that contacts the developing roller 62 and a support blade (support member) 369 that supports the restriction portion 368. .

  The basic configurations of the restriction portion 368 and the support blade 369 in the fourth embodiment are the same as those of the restriction portion 68 and the support blade 69 in the first embodiment.

  In the fourth embodiment, as shown in FIG. 13, the restricting portion 368 is configured such that the front portion 368b of the abutting portion is made of a foam and can be given a softer property than the abutting portion 368a.

  With this configuration, according to the doctor blade 367 of the fourth embodiment, as shown in FIG. 13, the contact portion front portion 368b of the restricting portion 368 is crushed, thereby absorbing the blade pushing-up action by the aggregated toner. As a result, the generation of toner layer streaks and the accompanying image defects can be suppressed.

  In addition, the restriction portion 368 is made of the same kind of rubber material, the contact portion 368a is made solid, and the contact portion front portion 368b is formed in a foam shape, so that the affinity of the joint portion is also improved. It is possible to provide a blade material that is high, reliable, and exhibits the effect of the present application at low cost.

  As a first modification of the fourth embodiment, as shown in FIG. 14, the low-hardness member 368 b 1 may be provided in a partial region on the opposite side to the contact surface of the contact portion front portion 368 b with the developing roller 62. . Further, as a second modification, as shown in FIG. 15, the low hardness member 368 b 2 may be provided in a partial region on the contact surface side of the contact portion front portion 368 b with the developing roller 62.

  In particular, as shown in FIG. 14, when the low-hardness member 368b1 is provided on the side opposite to the contact surface with the developing roller 62, restrictions on contamination and surface properties are alleviated, and therefore relatively inexpensive materials are used. This is possible and is more effective in reducing costs.

(Example 5)
Next, a fifth example of the doctor blade configuration characteristic of the present embodiment will be described with reference to the drawings.
FIG. 16 is an explanatory diagram showing the configuration of Example 5 of the doctor blade of this embodiment.

  As shown in FIG. 16, the doctor blade 467 of the fifth embodiment is configured by a restricting portion 468 mainly composed of an elastic member. That is, the supporting member that supports the restricting portion 468 is not provided.

One end of the restricting portion 468 is held by a fixing member 469.
The fixing member 469 is disposed on the downstream side in the rotation direction of the developing roller 62 with respect to the contact portion 468a between the restriction portion 468 and the developing roller 62, and is disposed in a state of protruding the regulating portion 468 toward the upstream side in the rotation direction. ing.

  The restricting portion 468 has a notch 468c formed in a region near the upstream side in the rotation direction of the developing roller 62 relative to the contact portion 468a, that is, a part of the contact portion front portion 468b (a portion on the free end side). Yes.

  The configuration of the notch 468c may be the same as the notch 68c formed in the restricting portion 68 of the first embodiment.

  With this configuration, according to the doctor blade 467 of the fifth embodiment, as in the case of the doctor blade 67 of the first embodiment, the notch portion 468c of the front portion 468b of the contact portion is crushed, so that the blade is pushed up by the aggregated toner. Since the action can be absorbed, generation of toner layer streaks and accompanying image defects can be suppressed.

  In addition, when comprised only by the restriction | limiting part 468 by an elastic member like the doctor blade 467 of Example 5, a contact force does not change by the influence of the characteristic change of an elastic member, a permanent distortion, etc. by long-term use. It is necessary to select the material.

(Example 6)
Next, a sixth example of the doctor blade configuration characteristic of the present embodiment will be described with reference to the drawings.
FIG. 17 is an explanatory view showing a configuration of Example 6 of the doctor blade of the present embodiment, and FIG. 18 is an explanatory view showing a modified example in which the protruding direction of the doctor blade of Example 6 is reversed.

  As illustrated in FIG. 17, the doctor blade 567 according to the sixth exemplary embodiment includes a restriction portion (elastic member) 568 that contacts the developing roller 62 and a support blade (support member) 569 that supports the restriction portion 568. .

The restricting portion 568 is composed of an elastic member made of a rubber member or the like. Further, a notch portion 568c similar to the notch portion 68c of the first embodiment is provided on the front portion 568b of the restricting portion 568.
The support blade 569 is configured using a phosphor bronze plate, a stainless plate, or the like.

  The schematic configuration of the doctor blade 567 of the sixth embodiment is substantially the same as that of the doctor blade 67 of the first embodiment.

  According to the doctor blade 567 of the sixth embodiment, the notch 568c is crushed so that the blade pushing-up action by the agglomerated toner can be absorbed more. Therefore, similar to the doctor blade 67 of the first embodiment, Occurrence and accompanying image defects can be suppressed.

  Furthermore, the doctor blade 567 of Example 6 has a support blade 569 made of sheet metal or the like, so that it can stably maintain the applied pressure for a long time, and has characteristics suitable for toner layer regulation with respect to the elastic body portion of the blade. Therefore, it is possible to select materials and shapes that give priority to the above, and it is useful for more stable performance and cost reduction.

  If the protruding direction of the support blade 569 with respect to the developing roller 62 is set so as to be a so-called “belly contact” where the contact portion 568a of the restricting portion 568 contacts the developing roller 62 on the surface, as shown in FIG. In addition, it may be forward with respect to the rotation direction of the developing roller 62, or may be reverse (counter direction) as shown in FIG.

(Example 7)
Next, a seventh example of the doctor blade configuration characteristic of the present embodiment will be described with reference to the drawings.
FIG. 19 is an explanatory view showing the configuration of Example 7 of the doctor blade of the present embodiment, FIG. 20 is an explanatory view showing a modified example in which the protruding direction of the doctor blade of Example 7 is reversed, and FIG. It is explanatory drawing which shows the comparative example of a doctor blade.

  As shown in FIG. 19, the doctor blade 667 according to the seventh embodiment includes a restriction portion (elastic member) 668 that contacts the developing roller 62 and a support blade (support member) 669 that supports the restriction portion 668. .

  The basic configurations of the restriction portion 668 and the support blade 669 in the seventh embodiment are the same as those of the restriction portion 68 and the support blade 69 in the first embodiment.

  The support blade 669 is configured to hold the restricting portion 668 at a position where its free end portion (on the opposite side to the fixed end with respect to the developing device) 669a extends beyond the contact portion 668a to the opposite side to the fixed end. Has been. That is, the support blade 669 is disposed so as to cover the upper portion of the contact portion 668a.

  According to the doctor blade 667 of the seventh embodiment, the support blade 669 can surely press the contact portion 668a of the restricting portion 668 against the developing roller 62, so that a desired blade contact force by the support blade 669 can be obtained. Thus, the degree of freedom in attaching the developing unit to the developing unit main body can be increased, and more stable toner layer forming conditions can be provided.

  The protruding direction of the support blade 669 with respect to the developing roller 62 may be forward with respect to the rotating direction of the developing roller 62 as shown in FIG. 19, or the reverse direction (counter) as shown in FIG. Direction).

  Further, regarding the selection of the protruding direction of the support blade 669 with respect to the developing roller 62, if priority is given to the pressure absorption of the contact portion front portion 668b, as shown in FIG. 20, the notch portion of the contact portion front portion 668b. A configuration in which the upper portion of 668c is not pressed by the support blade 669 is preferable. On the other hand, when giving priority to chattering, vibration and noise suppression of the support blade 669, it is preferable that the protruding direction of the support blade 669 is forward with respect to the rotation direction of the developing roller 62 as shown in FIG. . Therefore, it may be appropriately selected according to the use conditions.

  As shown in FIG. 21, when the free end 669a at the tip of the support blade 669 is located on or near the contact portion 668a of the restricting portion 668, the fixing position of the support blade 669 to the developing device 6 is slightly small. Since the contact force of the restricting portion 668 with respect to the developing roller 62 greatly changes due to the deviation, it is necessary to improve the mounting accuracy, and it becomes difficult to ensure the stability of toner layer formation.

  Since it comprised as mentioned above, according to embodiment and Example mentioned above, it is equipped with the doctor blade 67 which regulates the layer thickness of the developer carry | supported on the surface of the developing roller 62 as a structure of the developing device 6, The blade 67 includes a restricting portion 68 made of an elastic member that abuts the developing roller 62 and a support blade 69 that supports the restricting portion 68 so that the restricting portion 68 abuts the developing roller 62 in surface contact. Thus, the restricting portion 68 is configured such that the hardness of the abutting portion front portion 68b is lower than the hardness of the abutting portion 68a with the developing roller 62. Even if the pushing-up action occurs, the pushing force due to the agglomerated toner is absorbed by the deformation of the abutting portion front portion 68b, and the pressure distribution of the abutting portion 68a is made constant to achieve a desired value. Because that can be sustained state, it is possible to perform stable toner layer formation.

  As described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope not departing from the gist of the present invention are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 6 Developing apparatus 62 Developing roller 67,167,267,367
467, 567, 667 Doctor blade (developer regulating member)
68,168,268,368,468,568,668 Restriction part (elastic member)
68a, 268a, 368a, 468a, 568a, 668a Contact part 68b, 168b, 368b, 468b, 568b, 668b Contact part front part 68c, 68c1, 168c1, 168c2,
168c32, 168c33, 268c,
268c11, 468c, 568c, 668c Notch (removed part)
68c3 Hollow portion 68d, 268d, 268d1, 268d2 Opening 69, 169, 269, 369, 569, 669 Support blade (support member)
268L1 Tangent line 268c1 Surface 268e on the lower side of the notch 368e Surfaces 368b1, 368b2 facing the developing roller Low hardness member 469 Fixed member 669a Free end

Claims (10)

A developing roller provided in an electrophotographic image forming apparatus for supplying a developer to a photoconductor provided in the image forming apparatus to develop an electrostatic latent image formed on the photoconductor; In a developing device comprising a developer regulating member that regulates the layer thickness of the developer carried on the surface,
The developer regulating member includes an elastic member that contacts the developing roller, and a support member that supports the elastic member,
The elastic member is brought into contact with the developing roller by surface contact,
The developing device according to claim 1, wherein the elastic member is configured such that the hardness of a region near the upstream side in the rotation direction of the developing roller is lower than the hardness of the contact portion with the developing roller.   2. The developing device according to claim 1, wherein the elastic member has a part of a region near the upstream side in the rotation direction of the developing roller with respect to the contact portion.   The developing device according to claim 2, wherein the cut portions of the elastic member are provided at a plurality of locations so as to overlap in the thickness direction of the elastic member. The cut portion of the elastic member is formed along the rotation direction of the developing roller, with an opening formed on the upstream side of the elastic member in the rotation direction of the developing roller,
The angle formed by the surface on the developing roller side inside the cut portion of the elastic member and the surface of the elastic member facing the developing roller is θ1,
The angle formed by the tangent line of the developing roller passing through the upstream end of the developing roller in the rotational direction of the contact portion between the elastic body and the developing roller and the surface of the elastic member facing the developing roller is θ2. When
θ1> θ2
The developing device according to claim 2, wherein the following condition is satisfied.   The developing device according to claim 4, wherein the cut portion of the elastic member is configured to penetrate in a thickness direction of the elastic member.   2. The elastic member is characterized in that a part of a region in the vicinity of the upstream side in the rotation direction of the developing roller is formed in a foam shape from a contact portion of the elastic member with the developing roller. The developing device according to any one of 5 to 5.   The developing device according to claim 1, wherein the support member is configured using a leaf spring member. The support member has one end as a fixed end fixed to the developing device main body side, the other end as a free end, and the elastic member is held on the free end side.
The free end is configured to hold the elastic member at a position extending beyond the contact portion between the elastic member and the developing roller to the side opposite to the fixed end. The developing device according to claim 7.   The developing device according to claim 1, wherein the developing roller is configured using a metal member. A developing roller for developing an electrostatic latent image formed on the photosensitive member by supplying a developer to the photosensitive member, and a surface of the developing roller. In an image forming apparatus that includes a developing device that includes a developer regulating member that regulates the layer thickness of the developer carried on the image forming apparatus and performs image formation by an electrophotographic method.
An image forming apparatus comprising the developing device according to claim 1 as the developing device.

Images