KR20040090204A - Image forming apparatus - Google Patents

Abstract

PURPOSE: An image forming apparatus is provided to maintain the thickness of a developer layer formed on a developer transfer roller even when the position of a developer quantity controller is varied. CONSTITUTION: An image forming apparatus includes a photosensitive drum(10) on which an electrostatic latent image is formed, a developer(5), a developer transfer roller(32), a developer quantity controller(37), and a supporting member(35). The developer transfer roller transfers the developer to the photosensitive drum. The developer quantity controller is formed of an elastic plate and controls the quantity of developer on the developer transfer roller. The developer quantity controller has a bent portion extended from the free end thereof at an angle of approximately 70 to 100 degrees. The supporting member supports the developer quantity controller.

Description

Image Forming Device {IMAGE FORMING APPARATUS}

The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus in which a developer amount regulating member is improved to uniformly form a developer layer on a developer carrier.

In general, an image forming apparatus refers to an apparatus for transferring an image signal in the form of a visible image on a paper, which is a printing medium, in accordance with a digital signal input from a computer or a scanner.

Such an image forming apparatus includes a counseling member on which an electrostatic latent image is formed, a developing apparatus for developing a developer on the counseling member, a transfer means for transferring the developer developed on the counseling member to paper, and the like. A desired image is printed on a sheet of paper, which is called an electrophotographic method. In addition, the electrophotographic image forming apparatus is used in various fields such as a laser beam printer, an LED printer, and a digital copier.

Hereinafter, the electrophotographic image forming apparatus will be described.

1 and 2 are schematic diagrams of a conventional image forming apparatus 101. As shown in this figure, the conventional image forming apparatus 101 includes a photosensitive member 110 which is a counseling member provided to be rotatable in a drum shape, and a charging roller 111 that electrically uniformly charges the surface of the photosensitive member 110. An optical unit 113 for converting an image signal into an optical signal 114 to form an electrostatic latent image on the photosensitive member 110, and a developing device 130 for developing the developer 105 on the photosensitive member 110. And a transfer roller 115, which is a transfer means for transferring the developer 105 developed on the photosensitive member 110 to the paper 103, and a waste developer remaining on the photosensitive member 110 after being transferred to the paper 103. A waste developer recovery unit 120 having a cleaning blade 123 for collecting the 121, a paper feed roller 150 for supplying the paper 103 to the transfer roller 115, and a paper on which an image is formed ( The electrostatic latent image on the photosensitive member 110 is discharged from the discharge roller 160 for discharging 103 and the developer carrier 132 of the developing apparatus 130 which will be described later. The developer includes a power supply portion 125 for supplying a voltage for moving the 105. The

The developing apparatus 130 is provided with a developer accommodating portion 131 for accommodating the developer 105 and rotatably in a drum shape to transfer the developer 105 to the developing region 141 proximate to the photosensitive member 110. The developer conveying member 132, the supply roller 133 for attaching the developer 105 to the developer conveying member 132, and the developer 105 attached to the developer conveying member 132 are fixed. And a developer amount control member 137 for maintaining the thickness, and a support member 135 for supporting the developer amount control member 137.

The developer amount regulating member 137 is made of a metal plate having a thickness in the range of 0.1 mm to 0.4 mm to apply a constant contact pressure to the developer carrier 132, thereby attaching the developer attached to the developer carrier 132 ( 105) The layer is kept at a constant thickness. In addition, the developer amount control member 137 has a bent portion 139 that is bent to form an angle of approximately 45 degrees or less upward at a contact portion that contacts the developer transfer member 132. The thickness of the developer 105 formed on the developer carrier 132 is determined by the length of the bent portion 139. The thickness of the developer 105 formed on the developer carrier 132 after passing through the contact portion between the developer carrier 132 and the developer amount control member 137 is mainly defined by the developer amount control member 137. The amount of developer per unit area (mg / cm ² ) on the developer carrier 132 that has passed through the contact portion is represented, and the amount of developer per unit area (mg / cm ² ) is preferably 0.4 to 0.8.

With this configuration, the operation of the conventional image forming apparatus 101 will be described as follows.

First, an electrostatic latent image is formed on the surface of the photoconductor 110 charged by the charging roller 115 through the optical unit 113. The developer 105 is loaded on the developer conveying member 132 by the supply roller 133 and is transferred to the developing region 141 by the rotation of the developer conveying member 132. In this case, a developer 105 having a constant thickness is formed on the developer carrier 132 by the developer amount regulating member 137 provided on the developer carrier 132. Thereafter, the photosensitive member 110 is rotated and the developer 105 in the form of a visible image is developed on the photosensitive member 110 by pulling the developer 105 and pasting the electrostatic latent image while passing through the developing region 141. At this time, the developer 105 transferred to the developing region 141 spaced apart by a predetermined interval between the developer carrier 132 and the photosensitive member 110 may move to the electrostatic latent image on the photosensitive member 110 by the power supply 125. do. Thereafter, when the paper 103, which is a printing medium, is supplied to the transfer roller 115 by the paper feed roller 150, the developer adhered to the photosensitive member 110 by the high pressure and the electrostatic force applied to the transfer roller 115 ( 105 is transferred to the paper 103. Then, the paper 103 on which the image is formed is discharged out of the apparatus through the discharge roller 160 to complete printing.

However, in the conventional image forming apparatus 101, the thickness of the developer 105 layer formed on the developer carrier 132 is determined by the length of the bent portion 139 of the developer quantity regulating member 137. The length of the bent portion 139 is sensitively changed even when the assembly position of the developer quantity regulating member 137 is slightly changed. Therefore, when the length of the bent portion 139 is changed, the thickness of the developer 105 formed on the developer carrier 132 is changed, such that the developer 105 is excessively or insufficiently transferred to the paper 103. There is a problem that the quality of the image formed on the paper 103 is lowered.

Accordingly, it is an object of the present invention to provide an image forming apparatus capable of appropriately maintaining the thickness of a developer layer formed on a developer carrier even when the assembly position of the developer quantity regulating member changes slightly.

1 is a schematic diagram of a conventional image forming apparatus;

2 is a schematic view of a developing apparatus provided in the image forming apparatus of FIG. 1;

3 is a schematic diagram of an image forming apparatus according to the present invention;

4 is a schematic view of a developing apparatus provided in the image forming apparatus of FIG. 3;

5 is a graph comparing the amount of the developer on the developer carrier with respect to the control angle of the image forming apparatus according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: Image forming apparatus 3: Paper

5: developer 10: consultation delay

11: charging roller 13: optical unit

14 optical signal 15 transfer roller

20: lung developer recovery unit 21: lung developer

23: cleaning blade 25: power supply

30: developing device 31: developer accommodating part

32: developer carrier 33: feed roller

35 support member 37 developer amount regulating member

39: bend portion 41: developing area

According to the present invention, an image forming apparatus having a counseling member in which an electrostatic latent image is formed and a developer developed in the electrostatic latent image of the counseling member, comprising: a developer for transferring the developer to the counseling member; Songche; A developer amount regulating member provided with a plate-shaped elastic body so as to constantly regulate the amount of the developer on the developer conveying body, and having a bent portion extending from the free end at an angle of about 70 to 100 degrees; And a support member for supporting the developer amount control member, wherein the restricting angle of the developer amount control member is from 0 ° to 12 °.

Here, the bent portion preferably forms an angle of approximately 90 degrees from the free end of the developer amount regulating member.

The amount of deformation of the developer regulating member in contact with the developer carrier is preferably 1.5 mm to 3.0 mm.

The developer carrier is preferably made of NBR having a hardness of about 50 to about 80.

It is preferable that the surface roughness Rz of the circumferential direction of the said developer conveyance body is 3 micrometers-10 micrometers.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 3 and 4, the image forming apparatus 1 according to an embodiment of the present invention has a counseling member 10 on which an electrostatic latent image is formed and a surface of the counseling member 10. The charging roller 11 electrically and uniformly charged, the optical unit 13 converting an image signal into an optical signal 14 to form an electrostatic latent image on the counseling member 10, and on the counseling member 10. A developing apparatus 30 for developing the developer 5, a transfer roller 15 which is a transfer means for transferring the developer 5 developed on the consultation body 10 to the paper 3, and a paper. The waste developer recovery part 20 having a cleaning blade 23 for collecting the waste developer 21 remaining on the consultation support body 10 after transfer to (3) and the transfer roller 15 to the paper 3. On the consultation body 10 from a paper feeding unit (not shown) for supplying the ink, a paper discharge unit (not shown) for discharging the paper 3 on which the image is formed, and the developer carrier 32 of the developing apparatus 30 to be described later. It includes a power supply 25 for supplying a voltage to move the developer (5) to the electrostatic latent image of the.

The consultation member 10 has an electrostatic latent image formed on the surface thereof by the optical unit 13, and transfers the developer 5 from the developer carrier 32 of the developing apparatus 30 to be described later in the developing region 41. It is preferable to rotate so that it can be transferred to the paper 3 by the transfer roller 15. In addition, the counseling member 10 may be a photosensitive drum or a photosensitive member provided to be rotatable in a drum shape, and may be provided in another form to form an electrostatic latent image.

The developing apparatus 30 includes a developer accommodating part 31 accommodating the developer 5 and a developing area 41 in which the developer 5 accommodated in the developer accommodating part 31 is adjacent to the consultation member 10. The developer conveying body 32 to be transported to the developer, the supply roller 33 for attaching the developer 5 onto the developer conveying body 32, and the developer 5 attached to the developer conveying body 32. And a developer amount regulating member 37 for maintaining a layer of a predetermined thickness, and a support member 35 for supporting the developer amount regulating member 37.

The developer 5 is preferably one-component non-magnetic toner, but of course other developer toners may be used.

The developer conveying member 32 is rotatably provided in a drum shape so that the developer 5 contained in the developer accommodating portion 31 can be transferred to the developing region 41. In addition, the developer carrier 32 is preferably a non-magnetic conductive rubber roller, but more preferably made of NBR (Acrylonitrile Butadiene Rubber) having a hardness (JIS A Scale) of about 50 to 80 degrees. In addition, it is preferable that the surface roughness Rz of the circumferential direction of the developer conveyance body 32 which is a non-magnetic conductive rubber roller is 3 micrometers-10 micrometers.

The developer amount regulating member 37 is provided with a plate-shaped elastic body so as to constantly regulate the layer of the developer 5 on the developer carrier 32, one side of which is supported by the support member 35, and the other side The free end has a bent portion 39 extending from the free end at an angle of about 70 ° to 100 °. In addition, the developer amount regulating member 37 generates a frictional charge with the developer 5 attached on the developer carrier 32 to charge the developer 5 to a certain polarity.

In addition, the developer amount regulating member 37 preferably uses a metal sheet having a thickness of 0.05 mm to 0.1 mm having an elastic force. The metal plate is preferably a stainless plate, a phosphor bronze plate, or a beryllium copper plate.

The bent portion 39 is preferably bent in a substantially "L" shape at an angle of approximately 90 degrees from the free end of the developer amount regulating member 37.

The developer amount regulating member 37 is supported by the supporting member 35 so that the free end thereof is provided to the developer conveying member 32 with a predetermined contact pressure (linear pressure).

At this time, as shown in Figure 4, the developer amount control member 37 is elastically deformed by the amount of deformation (δ) by the developer carrier 32, in this case the contact pressing force (f) by the deflection equation of the cantilever beam It can be expressed as follows.

f is the contact force (gf / cm), E is the elastic modulus of the developer quantity regulating member, t is the thickness of the developer quantity regulating member, and L is the length of the elastically deformed developer quantity regulating member 37 (support member ( Distance to the free end of the developer quantity regulating member 37). The amount of deformation δ is preferably 1.5 mm to 3.0 mm.

Then, the developer amount regulating member 37 supported by the support member 35 is provided to have a predetermined pressure contact angle θ1. As shown in FIG. 4, the pressure contact angle θ1 is a portion of the tangent of the developer carrier 32 at the point where the free end of the developer quantity regulating member 37 contacts with the undeformed portion of the developer quantity regulating member 37. This angle is achieved. In addition, in the present invention, since the undeformed portion of the developer amount regulating member 37 is coupled in parallel to one side plate surface of the support member 35, the pressure contact angle θ1 is free of the developer amount regulating member 37. It may be represented by the angle formed by the tangent of the developer carrier body 32 is in contact with the end and one side plate surface of the support member 35. In addition, the pressure contact angle θ1 is preferably 15 ° to 20 °.

Then, when the free end of the developer amount control member 37 is elastically deformed by the deformation amount δ by the contact pressing force f, the undeformed portion of the developer amount control member 37, that is, the support member 35, The deformation angle θ3 of the free end of the developer amount control member 37 with respect to one side surface can be expressed by the following equation by the tip slope equation of the cantilever beam.

In this case, in the present invention, the control angle θ2 for regulating the thickness of the developer 5 layer on the developer carrier 32 is defined as follows.

θ2 = θ1-θ3

5 shows the amount of developer per unit area (mg / cm) formed on the developer carrier 32 after passing through the contact portion between the developer carrier 32 and the developer amount regulating member 37 according to the change of the control angle θ2. ² ) is a graph showing the change. As shown in this graph, it can be seen that the developer amount per unit area (mg / cm ² ) may be in the range of 0.4 to 0.8 when the regulation angle θ2 is in the range of 0 ° to 12 °. Then, the thickness of the developer 5 formed on the developer conveyance body 32 after passing through the developer quantity control member 37 is mainly on the developer conveyance body 32 which has passed through the developer quantity control member 32. It can be represented by the amount of the developer formed per unit area (mg / cm ^2), such that the amount of the developer per unit area (mg / cm ²⁾ is in the range from 0.4 to 0.8 is appropriate.

Therefore, in order to install the developer amount regulating member 37 on the developer carrier 32 so that the developer amount per unit area (mg / cm ² ) is in the range of 0.4 to 0.8, the regulation angle θ2 is set from 0 ° to 12 It is good to set it within the range. Thus, even if the assembly position of the developer amount regulating member 37 changes slightly within this range of the control angle θ2, the thickness of the developer 5 layer formed on the developer carrier 32 can be properly maintained.

Then, if the developer amount per unit area (mg / cm ² ) is formed on the developer carrier 32 in the range of 0.5 to 0.6, the developer amount regulating member so that the control angle θ2 is in the range of 3 ° to 10 °. What is necessary is just to install 37 (refer FIG. 5). In addition, since the developer amount control member 37 can be assembled with a tolerance within the range of the control angle θ2, the developer amount control member 37 can be easily assembled.

Looking at the operation of the image forming apparatus according to the present invention by such a configuration as follows.

First, the surface of the consultation member 10 is electrically uniformly charged by the charging roller 11, and then an electrostatic latent image is formed on the consultation member 10 through the optical unit 13. Then, the developer 5 is loaded on the developer conveying body 32 by the feed roller 33 and transferred to the developing region 41 by the rotation of the developer conveying body 32. At this time, the developer amount control member 37 forms a layer of the developer 5 having a predetermined thickness on the developer carrier 32. Thereafter, the counseling member 10 is rotated and pulls the developer 5 while passing through the developing region 41 and attaches the electrostatic latent image to develop the developer 5 in the form of a visible image on the counseling member 10. do. At this time, the developer 5 transferred to the developing region 41 spaced apart from the developer carrier 32 and the counseling member 10 by a predetermined interval is moved to the electrostatic latent image formed on the counseling member 10. What is necessary is just to apply the voltage which overlapped DC and AC to the developer carrier 32 via 25). Then, when the paper 3 is supplied to the transfer roller 15 by a paper feeding unit (not shown), the developer 5 attached to the consultation body 10 by the high pressure and the electrostatic force applied to the transfer roller 15. Is transferred to the paper 3. Then, the developer 5 transferred to the paper 3 is fixed to the paper 3 by the heat and pressure of the fixing unit (not shown). Thus, the image fixed on the sheet 3 is discharged out of the apparatus via a discharge unit (not shown) to complete printing.

As described above, the image forming apparatus according to the present invention is provided with a plate-shaped elastic body so as to constantly regulate the amount of the developer on the developer carrier, and has a developer amount regulation having a bent portion extending at an angle of about 70 ° to 100 ° from the free end thereof. And a support member for supporting the developer quantity regulating member, and the control angle of the developer quantity regulating member is provided so as to be in a range of 0 ° to 12 °, so that the developer quantity regulating member can be easily assembled, and Even if the assembly position varies slightly within this control angle range, not only can the thickness of the developer layer formed on the developer carrier be properly maintained, but also the thickness of the developer formed on the developer carrier can be properly maintained. It is possible to prevent the deterioration of the image formed on the paper by being properly transferred to the paper without being excessive or lacking.

As described above, according to the present invention, assembling of the developer quantity regulating member is easy, and even if the assembly position of the developer quantity regulating member changes slightly, the thickness of the developer layer formed on the developer carrier can be properly maintained. In addition, since the thickness of the developer formed on the developer carrier can be properly maintained, the developer can be properly transferred to the paper to prevent deterioration of the image formed on the paper.

Claims (5)

An image forming apparatus having a counseling member on which an electrostatic latent image is formed, and a developer developed on the electrostatic latent image of the counseling member, A developer carrier for transferring the developer to the consultation member; A developer amount regulating member provided with a plate-shaped elastic body so as to constantly regulate the amount of the developer on the developer conveying body, and having a bent portion extending from the free end at an angle of about 70 to 100 degrees; It includes a support member for supporting the developer amount control member, And a restricting angle of the developer amount regulating member is 0 ° to 12 °. The method of claim 1, And the bent portion forms an angle of approximately 90 degrees from a free end of the developer amount regulating member. The method of claim 2, And the deformation amount of the developer regulating member in contact with the developer conveying member is 1.5 mm to 3.0 mm. The method according to any one of claims 1 to 3, The developer carrier is an image forming apparatus, characterized in that the hardness is made of 50 to 80 NBR. The method of claim 4, wherein The surface roughness (Rz) in the circumferential direction of the developer carrier is 3 µm to 10 µm.