JP2000234913A - Paper thickness detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable accurate measurement of paper thickness and suitable control of the pickup of toner, and improve printing quality of an electrophotography system printer and a copying machine by excluding that measuring error of paper thickness is caused by difference of reflectivity of a surface in a paper manufacturing process or the like. SOLUTION: A paper thickness detecting apparatus 1 consists of a reflecting part 6 which pivots seesaw-wise according to the thickness t of paper material 10 passing a specified position and changes the inclination of a reflecting surface, a light projecting part 2 which casts a light almost rectangularly to the reflecting surface, and a light receiving part 3 as a two-divided photo detecting element which detects displacement generated by the inclination of the reflecting surface 6a of a light from the light projecting part 2. As a result, it is excluded that measuring error of paper thickness t is caused by difference of reflectivity of the surface in a paper manufacturing process or the like, and accurate measurement of paper thickness (t) is enabled, so that a problem is solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper thickness detecting device provided in an electrophotographic printer or copier for improving print quality.

[0002]

2. Description of the Related Art FIG. 6 shows an example of the configuration of a conventional paper thickness detecting device 90 of this type. The paper thickness detecting device 90 includes a light emitting section 91 such as an LED lamp and a position sensing device. And a light receiving section 92 are provided in an appropriate case 93. It should be noted that a processing circuit 94 for processing the output from the light receiving unit 92 is also integrated as necessary.

FIG. 7 shows a use state of the paper thickness detecting device 90. For example, in a printer or the like, the paper thickness detecting device 90 is provided at a portion where the paper material 10 passes before printing is performed. The light projecting unit 91 moves the paper 10
The light is emitted in an appropriate oblique direction so that the reflected light is incident on the light receiving unit 92.

At this time, the position on the light receiving portion 92 to which the light emitted from the light projecting portion 91 and reflected by the paper material 10 reaches depends on the paper thickness t of the paper material 10, and the light receiving portion 9
2 is an output characteristic R as shown in FIG.
S, the output characteristic R
It is possible to measure the paper thickness t from S.

The reason for measuring the paper thickness t is as follows.
This is because recent printers and copiers require extremely high quality output such as printing and copying of color photographic images. This is because it is necessary to more accurately control the amount of toner attached.

[0006]

However, in the above-described conventional paper thickness detecting device 90, the paper thickness t is directly measured from the output of the light receiving section 92.
It is inevitable that the measurement accuracy is affected by the reflectance of 0. Here, the reflectance of the paper material 10 is not simply determined by the whiteness of the paper material 10, but varies even with the same whiteness due to other factors such as surface smoothness and gloss. As shown in the figure, the output RS moves in parallel as the reflectance increases or decreases.

Therefore, it is difficult for the conventional paper thickness detecting device 90 to accurately measure the paper thickness t due to the difference in the production company and the difference between the production lots even if the paper materials 10 have the same standard. When extremely high image quality is required, such as when printing or copying a color photographic image, the problem is that high quality print output or copy output cannot be obtained as a result because the optimal amount of toner is not set. Had occurred.

[0008]

The present invention, as a specific means for solving the above-mentioned conventional problems, comprises a light projecting section and a light receiving section, and uses a change in reflected light of light from the light projecting section. In a paper thickness detection device configured to detect a paper thickness of a paper material passing a predetermined position, the paper thickness detection device swings in a seesaw shape according to a paper thickness of the paper material passing the predetermined position. A reflecting portion that changes the inclination of the reflecting surface, a light projecting portion that projects the light at substantially right angles to the reflecting surface, and a two-divided light receiving element that detects a deviation caused by the inclination of the reflecting surface of light from the light projecting portion. The present invention solves the problem by providing a paper thickness detecting device comprising a light receiving unit.

[0009]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 is a paper thickness detecting device according to the present invention. The paper thickness detecting device 1 includes a light projecting unit 2 and a light receiving unit 3 housed in a case 4 and is required. In this case, the processing circuit 5 for processing the output from the light receiving section 3 is integrated in the case 4 as in the case of the conventional example.

The light projected from the light projecting unit 2 reaches the light receiving unit 3 at an appropriate position such as the case 4 or the light projecting unit 2 and the light receiving unit 3 in a shape suitable for detection, for example, a spot shape. Although the optical means such as the lens 4a for molding is provided as described above, it is not a part of the gist of the present invention, and the detailed description is omitted here. Further, in the present invention, the light emitting unit 2 integrated with the case 4,
A reflecting section 6 is prepared separately from the light receiving section 3, the processing circuit 5, and the like. The reflecting section 6 is provided in a passage through which a paper material 10 for measurement passes as shown in FIG. Have been.

The reflecting portion 6 is a flat plate having an appropriate planar shape such as a rectangular shape, and has one surface serving as a reflecting surface 6a, and a rotating shaft capable of swinging the reflecting surface 6a in a seesaw shape. 6b is provided orthogonal to the passing direction of the paper material 10,
A projection 6c is provided on the back side of the reflection surface 6a, that is, on the surface facing the paper material 10 and at a position having an appropriate distance from the rotation shaft 6b.

Therefore, when the paper material 10 passes, the protrusion 6
c to be lifted by the rotation shaft 6b.
Turns, and the inclination of the reflection surface 6a changes. The degree of the change at this time is determined by the paper thickness t of the paper material 10, that is, the degree of the inclination of the reflection surface 6a described above. Is measured, the paper thickness t of the paper material 10 can be measured.

With the provision of the above-mentioned reflecting section 6, in the present invention, the configurations of the light projecting section 2 and the light receiving section 3 are also optimized so as to match the reflecting section 6. In 2, the direction in which light is emitted is a direction orthogonal to the surface of the paper material 10, and the position where the light is emitted is the reflection surface 6a and the position on the rotation axis 6b. . The light receiving section 3 is a photodiode or the like which is divided into a left half 3a and a right half 3b along the axial direction of the rotary shaft 6b. It is arranged along the axial direction of the moving shaft 6b.

FIG. 3 shows the principle of detection of the paper thickness detecting device 1 of the present invention. In order to facilitate understanding in the description, the light from the light projecting unit 2 is not illustrated because it is projected as a direction orthogonal to the surface of the paper material 10. When the paper material 10 having the standard paper thickness t passes, the reflection surface 6a of the reflection unit 6 is parallel to the surface of the paper material 10.

With the above setting, when the paper material 10 having the standard paper thickness t is supplied, the light receiving section 3 is provided with the left half 3
a and an equal amount of light reach the right half 3b (see FIG. 2). Therefore, the current output from the left half 3a is converted into a voltage by the current-voltage conversion circuit 5a in the processing circuit 5, and the current output from the right half 3b is similarly converted into a voltage by the current-voltage conversion circuit 5b. When both outputs are input to the differential amplifier circuit 5c, both outputs are the same, and the output from the differential amplifier circuit 5c is the "0" point indicated by the point P in FIG. Will not be.

When the paper thickness t of the paper material 10 is thinner than that set as a standard, the amount of light reflected by the reflecting surface 6a from the light projecting unit 2 is increased to the left half 3a. After the signal processing is performed by the processing circuit 5, a negative value indicated by a point Q in FIG. 4 is output, and when the paper thickness t is thicker than the standard, A positive value is output as indicated by a point R in the middle. Further, in the present invention, as is clear from the above description, the paper thickness t =
By setting 0 to the processing circuit 5, the presence or absence of the paper material 10 can be detected.

At this time, the more the paper thickness t deviates from the standard thickness, the more the output of the processing circuit 5 departs from the "0" point, and the output of the processing circuit 5 is represented by the curve S in FIG. Since it moves upward, knowing the position on the curve S makes it possible to detect the degree of difference of the paper thickness t of the supplied paper material 10 from the standard thickness. It is possible to make an adjustment so as to make the transfer amount to the material 10 constant.

Here, in the present invention, there is provided a reflector 6 whose degree of inclination changes according to the change of the paper thickness t.
Since the thickness t is measured by irradiating the light from the light projecting unit 2 to the reflection surface 6a, the reflectance of the paper material 10 can be made to have no relation to the measurement result in the measurement. Become.

In the configuration of the present invention, it is naturally considered that the amount of light reaching the light receiving unit 3 changes due to, for example, contamination of the reflecting surface 6a or deterioration of the light projecting unit 2. However, in the configuration of the present invention, the light receiving unit 3
Since the paper thickness t is measured by the ratio of the output of the left half 3a to the output of the right half 3b, the above-mentioned contamination and deterioration do not cause an error in the measurement.

FIG. 5 shows another embodiment of the present invention in a main part. Since the reflecting portion 6 always slides with the paper material 10, it is necessary to obtain durability. In some cases, a material that can withstand abrasion is selected. In this case, depending on the material, a sufficient reflectance may not be obtained on the reflection surface 6a. Therefore, the mirror surface 6d may be formed on the reflection surface 6a by an appropriate means such as aluminum deposition.

[0021]

As described above, according to the present invention, the reflecting portion which changes the inclination of the reflecting surface by swinging the paper thickness detecting device in a seesaw shape according to the paper thickness of the paper material passing through the predetermined position. When,
A paper thickness detecting device, comprising: a light projecting unit that projects the light at a substantially right angle to the reflecting surface; By doing so, the difference in the reflectance of the surface due to the papermaking process etc. will not cause a measurement error of the paper thickness, enabling accurate measurement of the paper thickness and appropriately controlling the amount of toner adhesion, This is extremely effective in improving the printing quality of electrophotographic printers and copiers.

Also, with the above configuration, the paper thickness detecting apparatus of the present invention measures the paper thickness by the ratio of the light receiving unit divided into two, so that, for example, deterioration of the light emitting unit or
The measurement accuracy is not affected by changes in the amount of reflected light due to contamination of the reflection section, etc., which means that the accuracy over the adjustment period is guaranteed, and the reliability of this type of paper thickness detection device is improved. Also exhibit extremely excellent effects.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a paper thickness detecting device according to the present invention.

FIG. 2 is a side view showing a reflection section which is a main part of the same embodiment.

FIG. 3 is an explanatory diagram illustrating an operation principle of the same embodiment.

FIG. 4 is a graph showing the output of the same embodiment.

FIG. 5 is an explanatory diagram showing a main part of another embodiment of the paper thickness detecting device according to the present invention.

FIG. 6 is an explanatory diagram showing a conventional example.

FIG. 7 is an explanatory diagram showing a use state of a conventional example.

FIG. 8 is a graph showing a measurement principle of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Paper thickness detection device 2 ... Light emitting part 3 ... Light receiving part 3a ... Left half 3b ... Right half 4 ... Case 5 ... Processing circuit 5a, 5b ... Current-voltage conversion circuit 5c ... Differential amplifier circuit 6 Reflecting portion 6a Reflecting surface 6b Rotating shaft 6c Projection 6d Mirror surface 10 Paper material t Paper thickness of paper material

Continued on the front page F term (reference) 2F065 AA24 AA30 BB01 BB15 CC02 DD13 FF43 GG12 HH04 HH13 JJ09 JJ23 LL04 LL11 NN20 PP22 QQ25 2F069 AA42 AA46 BB36 BB40 CC06 DD08 DD30 GG01 GG30 GG30 GG07 GG07 GG07 GG07 HGG

Claims (2)

[Claims] 1. A paper thickness detecting device comprising a light projecting unit and a light receiving unit, wherein a sheet thickness of a paper material passing a predetermined position is detected based on a change in reflected light of the light projecting unit. A reflecting unit that swings in a seesaw shape in accordance with the thickness of the paper material passing through the predetermined position and changes the inclination of the reflecting surface, and a projection unit that projects the reflection surface at a substantially right angle. A paper thickness detecting device, comprising: a light unit; and a light receiving unit that is a two-divided light receiving element that detects a deviation of light from the light projecting unit caused by an inclination of the reflection surface. 2. The paper thickness detecting device according to claim 1, wherein the reflection surface is mirror-finished.