JPH11194689A - Cleaning blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning blade whose longitudinal size accuracy is extremely good. SOLUTION: In the cleaning blade 3 in which a blade member 5 is attached to and along the edge of one side of a platelike holder 4 in the longitudinal direction of the holder, the blade member 5 is formed by mold integral- formation, and notches 20 are formed in the edge of the one side of the platelike holder 4 to which the blade is attached, in the parts near both longitudinal ends of the edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning blade for removing toner remaining on an outer peripheral surface of a photosensitive drum of an electrophotographic copying machine or the like.

[0002]

2. Description of the Related Art An electrophotographic copying machine is provided with a photosensitive drum provided with a photoconductor surface layer, and the outer peripheral surface of the photosensitive drum is uniformly charged. Forming an electrostatic latent image on the outer peripheral surface by exposing the toner, forming a toner image by attaching toner to the electrostatic latent image, and copying the image by transferring the toner image to copy paper or the like. is there. After the copying, as shown in FIG. 8, since the toner 2 remains on the outer peripheral surface of the photosensitive drum 1, it is necessary to remove the residual charged toner 2. This removal is performed by the cleaning blade 3. I have. The cleaning blade 3 is attached to a resin case 18 with a screw 7, and the elasticity of the blade member 5 is used to uniformly slide the end of the cleaning blade 3 against the outer peripheral surface of the photosensitive drum 1 to remove the toner 2. I have. As the cleaning blade 3, a thick plate-shaped soft urethane resin blade member 5 is generally fixedly formed at one end of a metal plate-shaped holder 4 having a substantially L-shaped cross section as shown in FIG. A cleaning blade 3 is used. A pair of mounting holes 6 through which screws 7 are inserted are formed at both ends of the plate-shaped holder 4 of the cleaning blade 3.

The cleaning blade 3 is, for example,
It is manufactured as follows. That is, first, FIG.
As shown in the figure, the upper mold 8a and the lower mold 8b are divided into each other. A molding space 17 for forming a blade is formed in the center of the mold, and the plate-shaped holder 4 is sandwiched between both sides of the molding space 17. A molding die 8 having a gap 9 formed therein is prepared. Then, the two plate-like holders 4 are projected in a state where one side ends thereof are opposed to the inside of the molding space 17 for forming the blade of the lower die 8b, and are positioned in the gap 9, so that the upper die 8a The lower mold 8b is clamped. Next, a molding member made of urethane resin is injected into the molding space 17 of the clamped molding die 8, cured, and then demolded.
As shown in (1), a molded product in which the two plate-shaped holders 4 are integrated by the wide blade member 10 is obtained. And
After the molded product is cooled to room temperature, rubber burrs 15 generated at both ends in the longitudinal direction of the wide blade member 10 are cut and removed along both end edges of the plate-like holder 4 as shown in FIG. Next, the center of the wide blade member 10 (a portion indicated by a chain line in FIG. 11) is cut and separated into two, and two cleaning blades 3 are formed.

[0004]

The cleaning blade 3 is manufactured by cooling a molded product to room temperature and then cutting the wide blade member 10 at the center to separate the blade into two pieces. However, since the heat-shrinkage of the soft urethane rubber wide blade member 10 is larger than that of the metal plate holder 4, the wide blade member 10 is attached to the plate holder 4 of the wide blade member 10 during the cooling. The vicinity of the uncut central portion (the portion to be cut later) shrinks more in the longitudinal direction than the portion attached to the plate-shaped holder 4.

In this state, when the center of the wide blade member 10 is cut, the plate-like holder 4 of the blade member 5 is cut.
Since the free end side not fixed to the plate member shrinks more than the portion fixed to the plate-shaped holder 4, the blade member 5 after cutting is moved in the directions of arrows A and B as shown in FIG. , And the shape in which both ends are jumped up. As described above, in the cleaning blade 3 manufactured by the mold integral molding as described above, the upper end edge of the blade member 5 is low near the center and high near both ends, so that the mounting hole 6
Of the blade member 5 (A dimension shown) from the line connecting the centers of the blade members 5 becomes uneven in the longitudinal direction.

FIG. 14 shows the variation of the dimension A in the longitudinal direction of the cleaning blade 3 (difference between the actual dimension and the set value, hereinafter referred to as "edge position"). It can be seen that the dimension A at the center of the blade member 5 is smaller than the set value (0 on the vertical axis in the figure), and increases toward the left and right ends of the blade member 5. In the cleaning blade 3, the edge position fluctuates only by B in the actual image area (the area where an image is actually formed) at the edge position. As described above, when the cleaning blade 3 is pressed against the photosensitive drum 1 due to the variation in the edge position, the blade nip width varies in the longitudinal direction of the cleaning blade 3 and uniform cleaning performance cannot be obtained. Occurs. In particular, recently, since the toner particle size has been reduced in accordance with the development of full color laser beam printers, there has been a demand for a high-precision cleaning blade 3 that minimizes variations in the edge position of the blade member 5 in the longitudinal direction.

The present invention has been made in view of such circumstances, and has as its object to provide a cleaning blade having extremely high dimensional accuracy in the longitudinal direction.

[0008]

In order to achieve the above object, a cleaning blade according to the present invention comprises a plate-shaped holder having a blade member attached to one side edge along the longitudinal direction thereof along the edge. A blade, wherein the blade member is formed by integral molding,
A first gist is that a notch is formed in a portion near one end on one side edge of the plate-like holder to which the blade is attached in the longitudinal direction.

Further, the cleaning blade of the present invention comprises:
A cleaning blade in which a blade member is attached to one side edge along the longitudinal direction of the plate-like holder along the edge thereof, wherein one side edge of the plate-like holder to which the blade is attached is a longitudinal side. The second gist is that the height is gradually reduced toward both ends of the.

That is, in the first cleaning blade of the present invention, a notch is formed in a portion near one of the longitudinal ends of one side edge of the plate-shaped holder to which the blade is attached. As a result, the portion where the notch is formed has a longer length from the end of the plate-shaped holder to the upper end of the blade member than the portion where the notch is not formed. The amount of heat shrinkage of the blade member in the portion where the notch is formed is larger than that in the other portions, so that the height near both ends of the blade member can be kept low. Then, since the variation in the edge position in the longitudinal direction of the blade member is reduced, uniform cleaning performance can be obtained when the cleaning blade is pressed against the photosensitive drum.

In the second cleaning blade of the present invention, one side edge of the plate-like holder to which the blade is attached is
Since the height is gradually reduced toward both ends in the longitudinal direction, the variation in the edge position in the longitudinal direction of the blade member is reduced and uniform, as in the case of the first cleaning blade. Cleanability is obtained.

[0012]

Next, an embodiment of the present invention will be described.

FIG. 1 shows a first embodiment of the cleaning blade of the present invention. This cleaning blade 3 is basically the same as that shown in FIG. 13, and the same parts are denoted by the same reference numerals. In this embodiment, a pair of rectangular notches 20 is formed in a portion of one side edge of the plate-shaped holder 4 to which the blade member 5 (shown by a chain line) is attached near both ends in the longitudinal direction. I have. The two notches 20 are formed at the left and right ends of the actual image area (positions closer to the inside by a predetermined distance from the left and right ends of the blade member 5).

It is preferable that the depth a of the notch 20 is set to 0.2 mm or more and 0.5 mm or less. If the depth a is 0.
If the thickness exceeds 5 mm, the spring force of the cleaning blade 3 changes, and if the depth a is less than 0.2 mm, the effect of reducing the variation in the edge position is poor. Further, it is preferable that the width b of the notch 20 is set to 0.5 mm or more. If the width b is less than 0.5 mm, the effect of reducing the variation in the edge position is poor.

By forming the notch 20 in the plate-shaped holder 4, the portion where the notch 20 is formed has a length from the upper end of the plate-shaped holder 4 to the upper end of the blade member 5. It becomes longer by a. Accordingly, the heat shrinkage of the blade member 5 becomes larger than that of the other portions, and the height near both ends of the blade member 5 can be kept low. as a result,
The variation of the edge position in the longitudinal direction of the blade member 5 is reduced.

FIG. 2 shows a cleaning blade according to a second embodiment of the present invention. In the cleaning blade 3, a pair of tapered portions whose height gradually decreases toward both ends in the longitudinal direction is provided at a portion near one longitudinal end of one side edge of the plate-shaped holder 4 to which the blade member 5 is attached. Part 2
1 is provided. The other parts are the same as those shown in FIG. 1, and the same parts are denoted by the same reference numerals. The height c of the tapered portion 21 is preferably set to 0.2 mm or more and 0.5 mm or less. If the height c exceeds 0.5 mm, the spring force of the cleaning blade 3 changes, and if the height c is less than 0.2 mm, the effect of reducing the variation in the edge position is poor. The length d of the tapered portion 21 is appropriately set in relation to the actual image area. In this embodiment, the actual image area is 7 m each at both ends of the cleaning blade 3.
m) is set to about 20 mm.

In the cleaning blade according to the second embodiment, the tapered portion 21 is formed in the plate-shaped holder 4 so that the edge of the blade member 5 is operated in the same manner as the notch 20 in the first embodiment. This has the effect of reducing positional variations.

FIG. 3 shows a cleaning blade according to a third embodiment of the present invention. The cleaning blade 3 has a slightly rounded tapered portion 22 instead of the tapered portion 21 of the second embodiment. The other parts are the same as those shown in FIG. 2, and similar parts are denoted by the same reference numerals. This also has the same operational effects as those shown in FIG.

FIG. 4 shows a cleaning blade according to a fourth embodiment of the present invention. In the cleaning blade 3, one side edge of the plate-shaped holder 4 to which the blade member 5 is attached is formed into a mountain shape by an inclined portion 23 whose height gradually decreases from the longitudinal center of the plate-shaped holder 4 toward both ends. Is formed. The height g of the peak is preferably set to be 0.2 mm or more and 0.5 mm or less. Height g is 0.
If it exceeds 5 mm, the spring force of the cleaning blade 3 changes, and if the height g is less than 0.2 mm, the effect of reducing the variation in the edge position is poor. The other parts are the same as those shown in FIG. 1, and the same parts are denoted by the same reference numerals. This also has the same operation and effect as those shown in FIG.

FIG. 5 shows a cleaning blade according to a fifth embodiment of the present invention. In the cleaning blade 3, one side edge of the plate-shaped holder 4 to which the blade member 5 is attached is rounded by the inclined portion 23 whose height gradually decreases from the longitudinal center of the plate-shaped holder 4 toward both ends. It is formed in a certain mountain shape. The other parts are the same as those shown in FIG. 4, and the same parts are denoted by the same reference numerals.
This also has the same effect as that shown in FIG.

Next, examples will be described together with comparative examples.

[0022]

EXAMPLES AND COMPARATIVE EXAMPLES In the cleaning blade 3 shown in FIG. 1, the width b of the notch 20 is 1 mm, and the depth a is
Was changed to 0.1 mm to 0.7 mm, and variations in edge positions in the longitudinal direction were evaluated. The results are shown in Table 1 below and FIG. As a comparative example, the notch 20
The cleaning blade not provided with was also evaluated. The edge position is the left end of the blade member 5,
7 mm from left end (left end of real image area), 10 mm, 12
0mm (blade member 5 center), 230mm, 233m
m (right end of the actual image area), 240 mm (blade member 5
At the right end).

[0023]

[Table 1]

As is clear from Table 1, the difference between the maximum value and the minimum value of the edge position in the real image area (M in Table 1)
AX-MIN) was smaller in each example than in the comparative example. In particular, the depth a of the notch 20 is 0.2 to 0.7 m
m gave good results.

Next, in the cleaning blade 3 shown in FIG. 1, the depth a of the notch 20 is set to 0.5 mm, and the width b of the notch 20 is changed to evaluate the variation of the edge position in the longitudinal direction. did. The same evaluation was performed on the cleaning blade 3 shown in FIG. The results are shown in Table 2 below and FIG. As a comparative example, a cleaning blade having no notch 20 was also evaluated.

[0026]

[Table 2]

As is clear from Table 2, the difference between the maximum value and the minimum value of the edge position in the real image area (M in Table 2)
AX-MIN) was smaller in each example than in the comparative example. Also, the difference became smaller as the width b of the notch 20 became larger.

[0028]

As described above, according to the first cleaning blade of the present invention, the notch is formed at a portion near one of the longitudinal ends of one side edge to which the blade of the plate-shaped holder is attached. ing. As a result, the portion where the notch is formed has a longer length from the end of the plate-shaped holder to the upper end of the blade member than the portion where the notch is not formed. The amount of heat shrinkage of the blade member in the portion where the notch is formed is larger than that in the other portions, so that the height near both ends of the blade member can be kept low. Then, since the variation in the edge position in the longitudinal direction of the blade member is reduced, uniform cleaning performance can be obtained when the cleaning blade is pressed against the photosensitive drum.

According to the second cleaning blade of the present invention, one side edge of the plate-like holder to which the blade is attached is formed so that the height gradually decreases toward both ends in the longitudinal direction. Therefore, as in the case of the first cleaning blade, the variation in the edge position in the longitudinal direction of the blade member is reduced, and uniform cleaning performance is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first embodiment of a cleaning blade of the present invention.

FIG. 2 is an explanatory diagram illustrating a cleaning blade according to a second embodiment of the present invention.

FIG. 3 is an explanatory view showing a third embodiment of the cleaning blade of the present invention.

FIG. 4 is an explanatory diagram illustrating a cleaning blade according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory view showing a cleaning blade according to a fifth embodiment of the present invention.

FIG. 6 is a graph showing variations in edge positions in the longitudinal direction of the cleaning blade of the present invention.

FIG. 7 is a graph showing variations in edge positions in the longitudinal direction of the cleaning blade of the present invention.

FIG. 8 is an explanatory diagram showing a use state of the cleaning blade.

FIG. 9 is a perspective view showing a conventional cleaning blade.

FIG. 10 is an explanatory diagram showing a manufacturing state of the cleaning blade.

FIG. 11 is an explanatory diagram showing a manufacturing state of the cleaning blade.

FIG. 12 is an explanatory diagram showing a manufacturing state of the cleaning blade.

FIG. 13 is an explanatory view showing a conventional cleaning blade.

FIG. 14 is a graph showing variations in edge positions in the longitudinal direction of the cleaning blade.

[Explanation of symbols]

 Reference Signs List 3 cleaning blade 4 plate holder 5 blade member 20 notch

Claims (2)

[Claims] 1. A cleaning blade in which a blade member is attached to one side edge along a longitudinal direction of a plate-like holder along the edge thereof, wherein the blade member is formed by integral molding. A cleaning blade, wherein a notch is formed in a portion near one of both ends in the longitudinal direction of one side edge to which the blade of the plate-shaped holder is attached. 2. A cleaning blade in which a blade member is attached to one side edge along a longitudinal direction of a plate-like holder along the edge thereof, wherein the one side edge to which the blade of the plate-like holder is attached. The cleaning blade is formed so that the height gradually decreases toward both ends in the longitudinal direction.