KR100547150B1 - Electrophotographic printer employing the same - Google Patents

Abstract

An electrophotographic printing machine employing a horizontally mounted type fixed toner cartridge is disclosed.

The disclosed electrophotographic printing machine includes a cabinet; A photosensitive drum provided in the cabinet, the electrostatic latent image being formed by charging and exposure; Supplying toner of a predetermined color to the photosensitive drum in a fixed state in the cabinet; a plurality of toner cartridges each having a developing roller disposed to face the photosensitive drum to develop an image; The angle θ ₄ between the line connecting the center of the developing roller and the center of rotation of the photosensitive drum and the line between the center of the developing roller of the toner cartridge and the center of rotation of the photosensitive drum are located between 90 ° and 180 °. Characterized in having a.

Description

Electrophotographic printer employing the same}

1 is a schematic configuration diagram showing an electrophotographic printing press employing a toner cartridge according to an embodiment of the present invention.

Figure 2 is a schematic perspective view showing the arrangement of four toner cartridges according to an embodiment of the present invention.

Fig. 3 is a perspective view illustrating the mounting state of four toner cartridges.

Figure 4 is an exploded perspective view showing one toner cartridge according to an embodiment of the present invention.

5 is a partial cross-sectional view showing a portion of FIG. 4.

FIG. 6 is a schematic view showing the arrangement of four toner cartridges for a photosensitive drum according to one embodiment of the present invention; FIG.

Fig. 7 is a schematic view showing the arrangement of four toner cartridges for a photosensitive drum according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10 ... Cabinet 15 ... Door

20, 120 ... photosensitive drum 23 ... Daejeon roller

25 ... Exposure unit 27 ... Transfer belt

29.Pressure roller 30 ... Toner supply unit

30C, 30M, 30Y, 30K ... toner cartridge

31.Elastic press means 33 ... Elastic member

34.Pressure element 35, 135C, 135K ... Developing roller

37.Gap ring 41 ... First cleaning unit

43 ... 2nd cleaning unit 45 ...

47. Antistatic lamp 49 ... Power supply

50 ... Fixer 60 ... Paper Unit

70 The paper feed unit 131 Housing

133 Feed roller 137 Guide member

139 ... Regulation blade 141 ... Agitator

143. Recovery member

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrophotographic printer employing a horizontally mounted type fixed toner cartridge, and more particularly, to an electrophotographic printer for optimizing the placement and specification of a toner cartridge for a photosensitive drum.

In general, an electrophotographic printing machine is an apparatus for printing an image by scanning light onto a photosensitive medium charged to a predetermined potential to form an electrostatic latent image, developing it with a toner of a predetermined color, and then transferring and fixing the image onto a paper.

This electrophotographic printing press is classified into wet and dry depending on the developer. A wet electrophotographic printing press uses a developer in which powdery toner is mixed with a liquid carrier. On the other hand, a dry transfer photograph printer uses a two-component developer in which a powdered carrier and a toner are mixed or a one-component developer without a carrier.

In addition, the electrophotographic printing press is classified into a black and white printing press and a color printing press depending on whether color is implemented. The monochrome printer uses one toner cartridge having a black color. The color printer performs toner supply and development using four toner cartridges each having yellow, magenta, cyan and black colors. In addition, the color printer is classified into a single path method and a multi-pass method according to a color image implementation method.

The single pass type printing machine employs an exposure unit and a charger corresponding to each of the four developing units for developing each color for one photosensitive medium, and can print a color image with one rotation of the photosensitive medium. Therefore, high speed printing is possible at the same speed as when printing a monochrome image even in color printing. On the other hand, by adopting a plurality of exposure units and a charger, the configuration thereof is complicated, and manufacturing costs increase.

The multi-pass printing machine employs one exposure unit, a charger, and four developing units for developing each color, and prints a full color image at four revolutions of the photosensitive medium. Therefore, there is a disadvantage in that arithmetic four times the printing time is required as compared to the single pass type printing machine. However, by employing one exposure unit and a charger, there is an advantage that the structure is simple and the manufacturing cost is low.

In consideration of the foregoing, as of July 24, 2002, a color image forming apparatus and a color image forming method (Patent Application No. 10-2002-0043586) have been filed, and as of July 4, 2003 It has been filed for an electrophotographic printing machine (Patent Application No. 10-2003-0045391).

The previously applied electrophotographic printing press adopts a multi-pass method. When looking at the configuration, the toner cartridge corresponding to each color is mounted horizontally with respect to the printer main body, and is fixed to the printer main body during the printing operation. Has a structure.

In such a configuration, a number of toner cartridges that contribute to development are fixed. Therefore, as compared with a printing machine having a structure in which a conventional toner cartridge operates, it is possible to fundamentally eliminate noise and vibration caused by the operation thereof. In addition, by omitting the structure for sliding or rotating the developer, it is possible to simplify the structure and reduce manufacturing costs.

On the other hand, in the printing machine employing the horizontally mounted type fixed toner cartridge, the height of each toner cartridge and the total amount of the toner cartridges are considered in view of the improvement in print quality, compact construction, reduction of assembly labor, and reduction in manufacturing cost. It is required to optimize the total effective height, the opening angle of the developing roller, and the specification of the photosensitive medium to a value within a predetermined range. In addition, it is required to specify an arrangement structure of a plurality of toner cartridges.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to provide a multi-pass type dry electrophotographic printing machine employing a fixed toner cartridge of a horizontal mounting type in which the standard of a photosensitive medium is optimized.

In order to achieve the above object, an electrophotographic printing machine according to the present invention comprises: a cabinet; A photosensitive drum provided in the cabinet, the electrostatic latent image being formed by charging and exposure; And a plurality of toner cartridges each having a developing roller arranged to face the photosensitive drum to develop an image by supplying toner of a predetermined color to the photosensitive drum while being fixed in the cabinet. The angle θ ₄ between the line connecting the center of the developing roller of the toner cartridge and the rotation center of the photosensitive drum and the line connecting the center of the developing roller of the toner cartridge and the center of rotation of the photosensitive drum positioned at the lowermost are 90 ° Characterized in that it has a value of 180 ° range.

Here, the angle θ ₄ is characterized by satisfying the following Conditional Expression 1.

<Condition 1>

Further, when the height of each of the plurality of toner cartridges is H ₁ , the following Conditional Expression 2 is satisfied.

<Condition 2>

26 ≤ H ₁ ≤ 33 [mm]

In addition, the plurality of toner cartridges are arranged in a stacked structure with a predetermined gap D _T spaced apart from each other, and supplies toners of black (K), yellow (Y), magenta (M), and cyan (C) colors, respectively. It is provided with four toner cartridges, and the total height H _TOT between the upper surface of the toner cartridge located at the top and the lower surface of the toner cartridge located at the bottom is characterized by satisfying the following conditional expression (3).
<Condition 3>
107 ≤ H _TOT ≤ 135 [mm]

In addition, the gap D _T is characterized by satisfying the following condition equation 4.

<Condition 4>

1.0 ≤ D _T ≤ 1.7 [mm]

Hereinafter, an electrophotographic printing press according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

1 is a schematic cross-sectional view showing an electrophotographic printing press according to an embodiment of the present invention.

Referring to the drawings, the electrophotographic printing press is provided with a cabinet 10, a photosensitive drum 20, a charging roller 23, an exposure unit 25, a transfer belt 27 provided inside the cabinet 10, Toner supply unit 30 is included.

The photosensitive drum 20 includes a cylindrical metal drum and a photoconductive layer formed on an outer circumference thereof.

The charging roller 23 is an example of a charger for charging the photosensitive drum 20 to a uniform potential. The charging roller 23 supplies electric charge while rotating in contact or non-contact state with the photosensitive drum 20 so that the photoconductive layer of the photosensitive drum 20 has a uniform potential. Here, it is also possible to use a corona charger (not shown) instead of the charging roller 23.

The exposure unit 25 is provided below the photosensitive drum 20, and scans light onto the photosensitive drum 20 charged at a uniform electric potential to form an electrostatic latent image corresponding to image information. In general, the exposure unit 25 uses a laser diode as a light source, scans the light irradiated from the light source through a rotating polygonal mirror or a hologram disk, and focuses a beam irradiated through the f-θ lens. Unit (Laser Scanning Unit: LSU) is adopted.

The toner supply unit 30 includes four toner cartridges 30C, 30M, 30Y, 30K, and each of the toner cartridges 30C, 30M, 30Y, 30K is cyan (C), magenta. Toners on solid powders of (M), yellow (Y) and black (K) colors are respectively accommodated. Each of the toner cartridges 30C, 30M, 30Y, 30K includes a developing roller 35 for supplying toner to the photosensitive drum 20 to form a toner image for the electrostatic latent image formed on the photosensitive drum 20. . Each of the toner cartridges 30C, 30M, 30Y, 30K is fixedly mounted in the cabinet 10 in a pressurized state by the elastic pressing means 31, and does not operate at the time of development. Here, a developing gap of about several tens to several hundred microns is formed between the developing roller 35 and the photosensitive drum 20 and developed in a non-contact manner. In developing the photosensitive drum 20 through the toner cartridges 30C, 30M, 30Y, and 30K, a toner cartridge corresponding to one color per rotation of the photosensitive drum 20 is applied. Only the development roller 35 contributes to development.

The transfer belt 27 is a belt that receives the image developed on the photosensitive drum 20 and transfers the image onto the printing paper P. The toner images of each color sequentially formed on the photosensitive drum 20 are sequentially transferred and superimposed on the transfer belt 27 to form a color image. The length of the transfer belt 27 is equal to or longer than the length of the printing paper P having the largest standard among printable sheets.

In addition, the printing press is a pressure roller 29, the first and second cleaning units 41, 43, the pre-transfer eraser unit 45, the antistatic lamp 47, the power supply 49 ), A fixing unit 50, and a paper feeding unit 60.

The pressure roller 29 is installed to face the transfer belt 27. The pressing roller 29 is spaced apart from the transfer belt 27 while the color image is transferred to the transfer belt 27. On the other hand, the pressure roller 29 is in contact with the transfer belt 27 at a predetermined pressure after the color image is completely transferred to the transfer belt 27, so that the transferred image is secondarily transferred to the printing paper P. do.

The first cleaning unit 41 removes the waste toner remaining on the outer circumferential surface of the photosensitive drum 20 after the toner image is transferred to the transfer belt 27. The second cleaning unit 43 removes the waste toner remaining in the transfer belt 27 after the image transferred to the transfer belt 27 is secondarily transferred onto printing paper.

The transfer prestatic unit 45 charges a charge of a non-image area in which the toner image on the photosensitive drum 20 is not formed before the toner image developed on the photosensitive drum 20 is transferred to the transfer belt 27. Remove Thereby, the transfer efficiency from the photosensitive drum 20 to the transfer belt 27 can be improved.

The antistatic lamp 47 removes electric charge remaining on the outer circumferential surface of the photosensitive drum 20 before charging. That is, the antistatic lamp 47 irradiates the outer circumferential surface of the photosensitive drum 20 with a predetermined amount of light to remove electric charges remaining on the surface of the photosensitive drum 20.

The power supply 29 provides a development bias power supply, a development prevention bias power supply, first and second transfer bias power supplies, and a charging bias power supply. Here, the development bias power supply is for developing the toner from the toner cartridges 30C, 30M, 30Y, 30K to the photosensitive drum 20, and the development prevention bias power supply is other than a specific color that contributes to development. Toner is prevented from being developed from the toner cartridge to the photosensitive drum 20.

The first transfer bias power source is a power source used to transfer the toner image from the photosensitive drum 20 to the transfer belt 27, and the second transfer bias power source transfers the toner image from the transfer belt 27 to the printing paper P. The power source used to The charging bias power source is a power source applied to the charging roller 23.

The fixing unit 50 fixes a toner image transferred to the printing paper P, and includes a pair of fixing rollers 51 and 53 which are engaged with each other at a predetermined pressure and rotated. At least one of the pair of fixing rollers 51 and 53 is provided with a heating means (not shown). Therefore, the toner image is fixed to the printing paper P by heat and pressure while the printing paper P having received the image passes through the fixing unit 50, thereby completing printing of the image.

The paper feeding unit 60 is a space in which the printing paper P to be supplied is loaded. This paper feeding unit 60 includes a first paper feeding cassette 61 which is mounted inside the cabinet 10 so as to be accessible from the outside. In addition, the paper feeding unit 60 may further include a second paper feed cassette 63 capable of mounting printing paper P and / or a multi-purpose feeder (hereinafter referred to as MPF) 65. have. This MPF 65 is mainly used for supplying transparencies or non-standard printing paper. The first and second paper feed cassettes 61 and 63 and the printing paper P loaded on the MPF 65 are conveyed by pickup rollers 67a, 67b and 67c.

The printing paper P fed through this paper feeding unit 60 is transferred to the path between the transfer belt 27 and the pressure roller 29 through the paper transfer unit 70. The paper conveying unit 70 includes a feed roller 71, a paper feed path 73 for guiding printing paper P between the feed roller 71 and the fixing unit 50, and a printing paper for duplex printing. A duplex path 75 for guiding the backfeed of P).

The paper on which the image is printed is discharged to the outside of the cabinet 10 through the discharge roller 79.

Looking at the printing process of the electrophotographic printing machine configured as described above are as follows.

Color printing on printing paper is implemented by using cyan (C), magenta (M), yellow (Y), and black (K) colors as primary colors, and superimposing them in a predetermined ratio. In this embodiment, toner images of each color are superimposed on the transfer belt 27 in the order of cyan (C), magenta (M), yellow (Y), and black (K), and transferred onto printing paper (P). Then, color printing is performed by fixing through the fixing unit 50.

First, the outer circumferential surface of the photosensitive drum 20 is charged to a predetermined potential by the charging roller 23. Subsequently, when the optical signal corresponding to the cyan (C) color image information is scanned by the exposure unit 25 to the rotating photosensitive drum 20, the portion where the light is scanned decreases the resistance and the photosensitive drum 20 The charge escapes from it. Therefore, an electrostatic latent image is formed on the outer circumferential surface of the photosensitive drum 20 while a potential difference is generated between the portion where the light is scanned and the portion that is not.

When the electrostatic latent image approaches the cyan toner cartridge 30C while the photosensitive drum 20 rotates, the developing roller 35 of the cyan toner cartridge 30C starts to rotate. The developing bias power is applied to the developing roller 35 from the power supply 49. At this time, a development preventing bias power source for preventing development is applied to the developing roller 35 of the other toner cartridges 30M, 30Y, 30K. Then, only the cyan color toner is developed on the outer circumferential surface of the photosensitive drum 20 across the developing gap Dg.

The cyan color toner image approaches the transfer belt 27 by the rotation of the photosensitive drum 20, and the image is transferred to the transfer belt 27.

After the toner image of cyan (C) color is completely transferred to the transfer belt 27, the toner images of magenta (M), yellow (Y), and black (K) color are also transferred to the transfer belt 27 in the above-described order. Overlaid while being transferred. In this way, a full color image is formed by overlapping each color.

During the above process, the pressure roller 29 is spaced apart from the transfer belt 27. When the full-color image is formed on the transfer belt 27, the pressure roller 29 presses the transfer belt 27 with the printing paper P therebetween, thereby secondarily transferring the image onto the printing paper.

To this end, when the tip of the color toner image formed on the transfer belt 27 reaches the point where the transfer belt 27 and the pressure roller 29 are in contact with each other, the tip of the printing paper P is transferred to the transfer belt 27. The printing paper P is fed from the paper feeding unit so as to reach the point where the and pressure rollers 29 are in contact with each other. When the printing paper P passes between the transfer belt 27 and the pressure roller 29, the color image is secondarily transferred to the printing paper P by the second transfer bias power supply. Subsequently, color printing is completed by fixing and discharging the color image onto the printing paper P by heat and pressure in the fixing unit 50. Thereafter, the first and second cleaning devices 41 and 43 remove waste toner remaining in the photosensitive drum 20 and the transfer belt 27, respectively, and the antistatic lamp 47 lights the photosensitive drum 20. Irradiation removes residual charge on the photosensitive drum 20.

In the electrophotographic printing machine according to the embodiment of the present invention configured as described above, each of the toner cartridges 30C, 30M, 30Y, 30K of each color is horizontally inward from one side of the cabinet 10. It has a configuration to be mounted in the direction.

FIG. 2 is a schematic perspective view showing an arrangement of four toner cartridges according to an embodiment of the present invention, and FIG. 3 is a perspective view illustrating the mounting operation of the four toner cartridges.

Referring to the drawings, each of the four toner cartridges 30C, 30M, 30Y, 30K is stacked in the order of cyan (C), magenta (M), yellow (Y), and black (K) color from bottom to top. Are arranged in a structure.

Each of these four toner cartridges 30C, 30M, 30Y and 30K contains toners of cyan (C), magenta (M), yellow (Y) and black (K) colors, respectively. Each of the toner cartridges 30C, 30M, 30Y, 30K includes a developing roller 35 for supplying the toner contained therein to the photosensitive drum (20 in Fig. 1). A gap ring 37 is provided at both ends of each developing roller 35. The gap ring 37 is such that the developing gap Dg is maintained between the developing roller 35 and the photosensitive drum 20, and has a diameter larger than that of the developing roller 35. Therefore, when the toner cartridges 30C, 30M, 30Y, 30K are mounted, the gap ring 37 is in contact with the outer circumferential surface of the photosensitive drum 20, thereby toner cartridges 30C, 30M, 30Y. By 30K being stopped, a developing gap is maintained between the developing roller 35 and the photosensitive drum 20.

Here, the four toner cartridges 30C, 30M, 30Y, 30K are mounted in the horizontal direction with the door 15 provided on the sidewall of the cabinet 10 open, and fixed after the installation is completed. Printing is performed in a controlled state.

To this end, the inner side of the door 15 includes elastic pressing means 31 for elastically pushing each of the toner cartridges 30C, 30M, 30Y, 30K in the closed position toward the photosensitive drum 20. desirable. In this case, the elastic pressing means 31 is elastically biased by an elastic member 33 such as a compression spring and the elastic member 33, and is rearward of the toner cartridges 30C, 30M, 30Y, 30K. And a pressing member 34 for contacting and pressing. This elastic pressing means 31 is not limited to the example shown in Figure 3, it is possible to perform various modifications of the structure.

As described above, the fixed type toner cartridge of the horizontal mounting type and the electrophotographic printing machine employing the same are required to optimize the specifications for improving the print quality, compacting the configuration, reducing the number of assembly operations, and reducing the manufacturing cost.

To this end, the height of each of the toner cartridges 30C, 30M, 30Y, 30K, the total effective height of the entire toner cartridge, the opening angle and diameter of the developing roller 35, the diameter of the photosensitive drum 20, and the photosensitive The relationship between the drum 20 and the developing roller 35 will be described, and the optimized standard will be described in detail.

Figure 4 is an exploded perspective view showing one toner cartridge according to an embodiment of the present invention, Figure 5 is a cross-sectional view of FIG.

Referring to the drawings, each of the toner cartridges 30C, 30M, 30Y, 30K according to the embodiment of the present invention includes a housing 131, a developing roller 35, and a supply roller (installed in the housing 131). 133, a guide member 137 for guiding the toner supply, and a regulating blade 139. 4 and 5 show the toner cartridge 30C for cyan (C) color as an example.

The developing roller 35 is installed in the housing 131 so as to be rotatable while a part surface thereof is exposed to the outside of the housing 131. This developing roller 35 supplies toner to the photosensitive drum 20 and develops an image by a potential difference.

Here, the relationship between the photosensitive drum 20 and the developing roller 35 satisfies the conditions of the following equations (1) and (2).

That is, when the diameter of the photosensitive drum 20 is D ₁ , the diameter D ₁ preferably satisfies the condition of Equation (1).

The condition of Equation 1 is such that each developing roller 35 can face the photosensitive drum 20 while mounting the toner cartridges 30C, 30M, 30Y, and 30K for each color in a horizontal state. Considering the minimum space required to do so. That is, in the above formula (1), when the value of the diameter D ₁ is set below the given lower limit value, it is difficult to arrange each toner cartridge and secure the effective developing gap Dg.

In addition, the photosensitive drum 20 considers jitter and color matching in transferring the toner image with respect to the transfer belt (27 in FIG. 1). That is, the diameter D ₁ of the photosensitive drum 20 is preferably set such that the outer circumferential length of the photosensitive drum is equal to the length of the transfer belt 27.

Here, the transfer belt 27 is an image such that it can be printed on usable printing paper such as A4 paper (length 297 mm), legal paper (14 inch length), and B4 paper (length 364 mm). The effective length contributing to the transfer is set to about 370 mm or more. Therefore, in consideration of the length of the transfer belt 27, the diameter D ₁ of the photosensitive drum 20 was set in the range of the above formula (1).

In Equation 1, considering the case of setting the diameter of the photosensitive drum 20 to 130 [mm] or more, it does not significantly affect the photosensitive and the transfer. However, the larger the diameter, the more space is occupied, the manufacturing cost increases rapidly, the manufacturing of the photosensitive drum 20 has a disadvantage that becomes difficult.

In addition, when the diameter of the developing roller is referred to as D ₂ , the relationship between the diameters D ₁ and D ₂ preferably satisfies the condition of Expression (2).

More preferably, the diameter D ₂ of the developing roller 35 is 14 [mm], and the diameter of the gap ring (37 in FIG. 2) is 14.4 [mm] so that the developing gap Dg has a value of 0.2 [mm]. It is set.

If the diameter of the developing roller 35 is less than 10.4 [mm], and it is out of the lower limit of Equation 2, it is difficult to print more than 5000 sheets based on 5% coverage without replacing the toner cartridge. do. On the other hand, if it is out of the upper limit of the given condition, the manufacturing cost of the developing roller 35 is rapidly increased, and mechanical arrangement with respect to the maximum size of the photosensitive drum 20 becomes difficult.

In addition, it is preferable that the opening angle θ ₁ of the developing roller has a value of approximately 25 ± 3 [Deg.].

Here, the opening angle θ ₁ is a line segment connecting the center of the developing roller 35 and the tip of the developing gap Dg formed between the developing roller 35 and the photosensitive drum 20, and the center of the developing roller 35. And the line segment connecting the rear end of the developing gap Dg.

The opening angle θ ₁ is a factor that determines the length of the developing gap Dg formed between the developing roller 35 and the photosensitive drum 20 together with the diameter of the developing roller 35. The opening angle θ ₁ is determined in consideration of the rotational linear velocity and diameter of the developing roller 35 and the bias potential applied to the developing roller 35. When the opening angle θ ₁ is set within the above range, Four or more prints are possible.

As described above, by setting the standard range of the photosensitive drum 20 and the developing roller 35, the lifespan of the developing roller can be minimized while ensuring the life of the developing roller to 5000 sheets or more, so that the manufacturing cost and Space layout can be optimized.

The feed roller 133 is rotated while being in contact with the developing roller 35 and is installed at a predetermined position in the housing 131 filled with the toner T of a predetermined color. The feed roller 133 is made of a sponge so that the toner T is easily attached to the outer surface thereof and has a large contact nip width with the developing roller 35.

The supply roller 133 attaches the toner T to the developing roller 35 and facilitates the supply flow of the toner. In this way, to supply the toner smoothly, a bias power source having a predetermined potential is applied to the supply roller 133 from the power supply (49 in FIG. 1). The toner supplied by the application of the bias power is charged to a predetermined potential. In addition, the supply roller 133 cleans the toner T remaining in the developing roller 35 after the development.

To this end, since the supply roller 133 is important to set the diameter position and rotation direction, and the arrangement position in relation to the developing roller 35, it will be described in detail.

This feed roller 133 rotates in the same rotational direction as the developing roller 35, that is, counterclockwise in FIG. Therefore, in the part in contact with the developing roller 35, the developing roller 35 and the supply roller 133 are rotated opposite to each other, thereby effectively performing the cleaning function. In addition, the feed roller 133 has a diameter D ₃ , the diameter D ₃ satisfies the condition of the equation (3).

The reason why the diameter D ₃ of the feed roller 133 is set within the condition range of Equation 3 is related to the diameter D ₂ of the developing roller mentioned through Equations 1 and 2. That is, the width of the nip with the developing roller 35 has a contact area of about 3 [mm] or more. In addition, it is a setting condition for maintaining the speed of the supply roller at approximately 189 [mm / sec], and setting the speed of the developing roller at approximately 174 [mm / sec] to allow cleaning and charging.

In other words, if the value falls outside the lower limit of Equation 3, in order to maintain a predetermined linear velocity on the outer circumferential surface, there is a problem in that the rotational speed of the supply roller is increased. If this is not satisfied, the cleaning and charging operations are performed smoothly. It doesn't work. On the other hand, if the deviation from the upper limit of the equation (3), the space occupied by the feed roller 133 becomes large. As a result, the height of the housing 131 of each toner cartridge 30C is increased, which in turn affects the size of the photosensitive drum 20. Therefore, it becomes the cause of the size of the whole press and manufacturing cost.

Looking at the arrangement of the supply roller 133 with respect to the developing roller 35 is as follows. Referring to FIG. 5, when setting the horizontal axis (X axis) and the vertical axis (Y axis) coordinates with respect to the center of the developing roller 35, the supply roller 133 is located in four quadrants (IV). When the angle formed by the line segment connecting the central axis of the roller 35 and the supply roller 133 and the X axis is θ ₂ , this θ ₂ satisfies Equation 4 below.

More preferably, the angle θ ₂ is approximately 21 degrees. Here, if the upper limit value of the equation (4) is out of the toner recovery through the supply roller 133 is not made smoothly, there is a problem that the height of the housing 131 is increased. On the other hand, if it is out of the lower limit value, the space between the guide member 137 and the supply roller 133 is not easily secured, and there is a problem that the toner supply flow is not constituted.

The regulating blade 139 controls the amount of feed delivered to the developing gap Dg in the toner supplied to the developing roller 35 through the supply roller 133 and the guide member 137. In addition, the regulating blade 139 prevents the toner filled in the housing 131 from leaking out through the portion in which the developing roller 35 is installed.

This regulating blade 139 is located in the third quadrant III when its tip sets a horizontal axis (X axis) and a vertical axis (Y axis) coordinate with respect to the center of the developing roller 35 in FIG. 5. . When the angle formed by the line segment connecting the distal end of the regulating blade 139 and the central axis of the developing roller 35 and the X axis is θ ₃ , this θ ₃ satisfies the following equation (5).

More preferably, the angle θ ₃ satisfies 49 °. Here, when the angle angle θ ₃ formed by the tip of the regulating blade 139 is out of the upper limit of Equation 5, the tip of the regulating blade 139 moves when the developing roller 35 is rotated, so that the quadrant of the above-described coordinates There is a risk of losing its function as it moves to (II). On the other hand, when the angle θ ₃ deviates from the lower limit, there is a fear that uncharged toner is supplied to the developing gap Dg together with the toner charged through the feed roller 133.

The regulating blade 139 is composed of a free end 139a which is in contact with the developing roller 35 and varies its degree of bending according to external pressure, and a fixed end 139b which fixes the free end 139a. do. Here, the tip pressure of the free end 139a maintains approximately 45 to 55 g / cm. And, the length L of the free end 139a has a value in the range of about 8.5 to 9.2 [mm]. In this way, by setting the standard and the arrangement of the regulating blade 139, the free end 139a of the regulating blade 139 is maintained at a constant tip pressure without being inverted by the rotation of the developing roller 35. Only used toner contributes to development.

Meanwhile, in addition to the above-described components, that is, the developing roller 35, the supply roller 133, the guide member 137, and the regulating blade 139, the housing 131 is rotatably installed to deliver the filled toner. An agitator 141 and a recovery member 143 for recovering excess toner delivered to the developing roller 35 side are included.

Here, referring to the cyan (C) color toner cartridge 30C as an example, the optimized size and arrangement of the developing roller 35, the supply roller 133, and the regulating blade 139 are mentioned, but this is the cyan color toner cartridge. The present invention is not limited to 30C, but is also applied to each of the toner cartridges 30M, 30Y, 30K for magenta (M), yellow (Y), and black (K) colors.

6 is a schematic cross-sectional view showing a portion of a toner cartridge and a photosensitive drum according to an embodiment of the present invention.

Referring to Fig. 6, the height of each of the toner cartridges 30C, 30M, 30Y and 30K, the effective height of the entire toner cartridge, and the arrangement of the photosensitive drum will be described.

First, the height H ₁ of each toner cartridge based on the cyan (C) color toner cartridge 30C is as follows. The height H ₁ of the toner cartridge 30C means the height of the housing 131, which is the diameter and arrangement of the developing roller 35, the supply roller 133, and the length of the regulating blade 139. And its minimum height is determined by placement.

In setting the standard of the toner cartridge 30C based on the above Equations 1 to 5, the height H ₁ of each toner cartridge 30C, 30M, 30Y, 30K is required at least 26 [mm]. .

Here, the height of the toner cartridges 30C, 30M, 30Y and 30K in consideration of the thickness of the frame constituting the housing 131 and the arrangement of the seal bracket and the recovery member 143 are considered. H ₁ preferably has a value of 31 [mm]. In the case of the black color toner cartridge 30K, on the other hand, in setting the height, not only the height is maintained at 31 [mm] as described above, but other toner cartridges are not disposed thereon, so that several millimeters are used. It is also possible to form higher, for example 33 [mm] in height.

Here, the toner cartridge height H ₁ can be freely designed to a value equal to or greater than the above value, but as the height increases, the diameter of the photosensitive drum 20 is required to increase, and the size of the printer main body increases, so that the compact and And lower cost.

In addition, the toner cartridges 30C, 30M, 30Y, and 30K are types that are mounted in the horizontal direction, and have a structure in which they are stacked in the height direction, and each toner cartridge is spaced apart by a predetermined interval D _T. . The interval D _T between these toner cartridges is preferably maintained at an interval of 1.6 to 1.7 [mm], and at least 1.0 [mm]. This is set in consideration of the mechanism tolerance of each of the toner cartridges 30C, 30M, 30Y, 30K, securing the space required for moving the toner cartridges horizontally, and the final coupling direction of each developing roller 35.

Here, the final bonding direction of the developing roller 35 is determined so that the center of the developing roller 35 of each of the toner cartridges 30C, 30M, 30Y, 30K is moved toward the center of the photosensitive drum 20. do. That is, the uppermost toner cartridge, for example, the toner cartridge 30K for black color, is completely moved while being spaced at a small distance downward from the point where the horizontal slide movement ends. On the other hand, the lowermost toner cartridge, for example, the cyan color toner cartridge 30C, is moved together at a small interval upwards from the point where the horizontal slide movement ends, and the coupling is completed. For this purpose, the interval D _T in the above range is required between the toner cartridges 30C, 30M, 30Y, 30K.

Therefore, when the height H ₁ of each of the above toner cartridges 30C, 30M, 30Y and 30K is set to 31 [mm] and the distance D _T is set to 1.6 [mm], the total height of the toner cartridge is H _TOT can be managed to 128.8 [mm]. On the other hand, when the height H ₁ of each toner cartridge is set to 26 [mm] and the distance D _T is set to 1.0 [mm], the H _TOT can be managed at a minimum of 107 [mm].

Here, the black color toner cartridge 30K is disposed at the top, and the sub-cavity portion 30K is provided on at least a part of the upper surface of the housing so that a large amount of black toner can be secured compared to the toner capacity of the other toner cartridge. -1) can be provided. This sub space part 30K-1 is provided to avoid the upper surface of the developing roller 35, so that it does not interfere with other components of the printing machine, for example, the transfer belt (27 in Fig. 1) during horizontal mounting.

The total height H _TOT of the four toner cartridges 30C, 30M, 30Y, 30K is preferably in the range of 107 to 135 [mm]. In addition, the height H _EF from the developing roller center of the toner cartridge 30K located at the top to the developing roller center of the toner cartridge 30C located at the bottom is four toner cartridges 30C, 30M, 30Y and 30K. It is desirable to have a maximum value of 98.1 [mm] while satisfying the minimum height to be mounted. This is a value required for managing the size of the entire press and the diameter of the photosensitive drum 20 within the ranges of the above Equations 1 and 2, and satisfying the condition of the Equation 6.

Considering the arrangement of the four toner cartridges 30C, 30M, 30Y and 30K with respect to the photosensitive drum 20 according to the first embodiment of the present invention, the top of the toner cartridge 30K provided at the top The angle formed by the line segment between the center of the developing roller and the center of the photosensitive drum 20 and the line segment between the center of the developing roller and the center of the photosensitive drum 20 of the toner cartridge 30K provided at the bottom (hereinafter referred to as a radial angle). θ ₄ satisfies the condition of equation (6). More preferably the radiation angle θ ₄ is approximately 94 °.

Thus, by setting the radiation angle θ ₄ , all the toner cartridges 30C, 30M, 30Y, 30K can be disposed on one side of the photosensitive drum 20, that is, on the left side of the photosensitive drum in FIG. The toner cartridges 30C, 30M, 30Y, 30K can be replaced conveniently. It is also possible to implement a compact deployment.

Herein, when the value of the radiation angle θ ₄ is outside the lower limit of Equation 6, the toner cartridges 30C, 30M, 30Y, 30K having the specifications in the range as described above may be replaced by a predetermined interval D _T. It cannot be placed while secured. On the other hand, if it is out of the upper limit of Equation 6, the position where the developing gap is formed for each toner cartridge is greatly changed. As a result, it is not possible to design a toner cartridge having a structure in which the installation angle of the feed roller 133 and the installation angle of the regulating blade 139 are identical to the developing roller 35.

Referring to Fig. 7, the arrangement of four toner cartridges 130C, 130M, 130Y and 130K with respect to the photosensitive drum according to the second embodiment of the present invention is shown. In this embodiment, each of the four toner cartridges 130C, 130M, 130Y, 130K is disposed on one side of the photosensitive drum 120, and in FIG. 7, all of the toner cartridges 130C, 130M, 130Y on the left side of the photosensitive drum. (130K) is characterized in that the arrangement angle is changed within the range in which it can be arranged.

That is, line segments formed by the center of the developing roller 135 and the center of the photosensitive drum 120 of the toner cartridge 130K located at the top of the present embodiment, and the developing roller which is a part of the toner cartridge 130C located at the bottom thereof. The angle between the center of the 135 and the line segment formed by the center of the photosensitive drum 120 is characterized in that it has a value in the range of 90 ° to 180 °.

In this case, in particular, when the angle is designed to be within about 100 ° or more and within 180 °, there is a disadvantage in that the layout design of the internal components of each toner cartridge must be different. However, since the toner cartridges 130C, 130M, 130Y, and 130K are each mounted horizontally, the toner cartridges 130C, 130M, 130Y, and 130K can be replaced on one side of the printing machine, thereby making it easy to replace the toner cartridges. In addition, the height of the toner cartridge can be set relatively freely than the overall height setting of the toner cartridge described with reference to FIG. 6, and there is an advantage that a space inside the housing in which the toner is accommodated can be relatively wide.

The toner cartridge configured as described above includes the diameter of the developing roller, the opening angle of the developing roller, the diameter of the feed roller and the arrangement position of the developing roller, the free end length of the regulating blade and the arrangement position of the blade tip, the height of each toner cartridge, And by characterizing the entire toner cartridge height within a limited range, there is an effect of compacting its configuration, reducing assembly labor, and reducing manufacturing costs.

In addition, the horizontally mounted fixed dry electrophotographic printing machine employing this toner cartridge optimizes the diameter of the photosensitive drum and the placement of the toner cartridge with respect to the photosensitive drum, thereby improving printing quality, making the overall configuration of the printing press compact, and manufacturing cost. There are effects such as saving and reduction of assembly labor.

Claims (6)

Cabinets; A photosensitive drum provided in the cabinet, the electrostatic latent image being formed by charging and exposure; And a plurality of toner cartridges each having a developing roller arranged to face the photosensitive drum to develop an image by supplying toners of a predetermined color to the photosensitive drum in a fixed state in the cabinet. An angle θ ₄ is formed between a line connecting the center of the developing roller of the toner cartridge positioned at the top and the rotation center of the photosensitive drum, and a line connecting the center of the developing roller of the toner cartridge located at the bottom of the photosensitive drum with the rotation center of the photosensitive drum. An electrophotographic printing machine having a value in the range of 90 ° to 180 °. The method of claim 1, The angle θ ₄ satisfies the following Conditional Expression 1. <Condition 1>

The method of claim 1, When the height of each of the plurality of toner cartridges is H ₁ , the following Equation 2 is satisfied. <Condition 2> 26 ≤ H ₁ ≤ 33 [mm] The method of claim 1, The plurality of toner cartridges are arranged in a stacked structure with a predetermined gap D _T spaced apart from each other, and four toners supplying toners of black (K), yellow (Y), magenta (M), and cyan (C) colors, respectively. With a cartridge, And an overall height H _TOT between the upper surface of the toner cartridge located at the top and the lower surface of the toner cartridge located at the bottom meets the following conditional expression (3). <Condition 3> 107 ≤H _TOT ≤ 135 [mm] The method of claim 4, wherein And the gap D _T satisfies Condition 4 below. <Condition 4> 1.0 ≤ D _T ≤ 1.7 [mm] The method according to claim 4 or 5, The total height H _EF between the center of the developing roller of the toner cartridge positioned at the top and the center of the developing roller of the toner cartridge located at the bottom thereof is a maximum of 98.1 [mm] while satisfying the minimum height at which the four toner cartridges are mounted. Transfer photo printing machine characterized in that it has a value.

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