JPH0545283A - Concentration sensing device of recorder - Google Patents

Abstract

PURPOSE:To equip a sensor with a satisfactory sensitivity and prevent the sensitivity direction from variation by locating the center of gravity of photo- receiving sensitivity at the center of a photo-receiving element, forming an electrode provided on the photo-receiving surface side so as to be symmetrical about the center of the sensitive region, and dislocating this region from the center of the element. CONSTITUTION:A photo-resistor element pellet 3a is placed on a table 3C installed in a lens of a photo-receiving element 3, and an electrode 3b is formed on the photo-receiving surface side. This electrode 3b is located in the center of the pellet 3a so as to generate symmetricity about the center. The electrode 3b is not sensitive for light, but the center of gravity of the photo-sensitive region excluding the electrode lies at the center of the element 3, and the center of gravity of the photo-receiving sensitivity does not vary even though the element 3 is rotated. Thereby the center of gravity of sensitivity can be put identical to the optical axis only by mounting an ADC sensor to an object material in such a way straight thereto, and the max. sensitivity can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device density detecting device.

[0002]

2. Description of the Related Art A recording device such as a copying machine or a facsimile detects the state of each part of xerography so as to maintain a high image quality for a long time even if the environment or the characteristics of a photosensitive material and a developer change. The developing bias, the toner dispensing, etc. are controlled based on the detection result, and the density is controlled so that the best image quality is always obtained. The applicant has already proposed an ADC (Automatic Density Control) sensor as shown in FIG. 4A for such concentration control. The ADC sensor 1 includes a light emitting element 2 in a case 4.
And the light receiving element 3 are resin-sealed, and the pinhole 6,
7, a seal member 5 made of glass or the like is provided on the front surface to prevent toner, paper dust, etc. from entering the pinholes, and the light emitting element and the light receiving element are provided with lead wires 11, 1 respectively.
2 is connected and taken out as a lead wire 13 from the rear surface side.

In detecting the density, the light from the light emitting element 2 is applied to the surface of the photosensitive material (not shown) through the pinhole 6 and the seal member 5, and the reflected light from the surface of the photosensitive material is received by the light receiving element 3 through the pinhole 7. The amount of received light corresponding to the toner density on the photosensitive material surface can be obtained, and the toner density on the photosensitive material surface can be detected.

[0004]

By the way, in the light receiving element 3 used in the ADC sensor 1, as shown in the plan view of FIG. 4 (b), the pellet 3a of the phototransistor is formed in the central region of the light receiving element lens. The electrodes 3b are arranged on the light receiving surface side thereof to convert the light incident on the region of the pellet 3a into electric energy. However, since the electrode 3b has no photosensitivity, the light receiving sensitivity center of gravity deviates from the center of the pellet. ing. Therefore, if the ADC sensor 1 is simply attached straight to the surface of the photosensitive material, the optical axis deviates from the gravity center of the light receiving sensitivity, and sufficient sensor sensitivity cannot be obtained.
The required sensor sensitivity could not be obtained unless the sensor was tilted variously and adjusted so that the optical axis was aligned with the light receiving sensitivity center of gravity of the pellet 3a.

For example, as shown in FIGS. 5 (a) and 5 (b), the sensor 1 is tilted in the direction of the central axis of the sensitive material 20 (direction B) and in the direction perpendicular to the central axis of the sensitive material 20 (direction A). When the sensitivity in the A direction and the sensitivity in the B direction are plotted on the abscissa and the ordinate, respectively, and a plurality of sensors were tested, the center of gravity of the photosensitivity was deviated from the center as in the region C of FIG. The result was. Therefore, if such an ADC sensor is simply arranged straight with respect to the surface of the sensitive material, the center of light-receiving sensitivity of the light-receiving element deviates from the optical axis, so that sufficient sensor sensitivity cannot be obtained.

The present invention is intended to solve the above-mentioned problems. Sufficient sensor sensitivity can be obtained simply by arranging the sensor in a straight line with respect to the surface of the photosensitive material so that the center of gravity of the photosensitivity is at the center of the element. It is another object of the present invention to provide a density detecting device for a recording device in which the direction of sensor sensitivity does not change regardless of the direction in which the light receiving element is rotated.

[0007]

The present invention comprises a light emitting element for irradiating a light-sensitive material with light and a light-receiving element for receiving reflected light from the light-sensitive material. The optical density on the light-sensitive material is obtained by the amount of light received. In the recording apparatus in which the density is controlled by the above, the light receiving element is configured such that the light receiving sensitivity center of gravity is at the element center.

Further, in the light receiving element, the electrodes formed on the light receiving surface side are formed symmetrically with respect to the center of the region having the light receiving sensitivity, and in the light receiving element, the center of the light receiving sensitivity is in the center of the element. It is characterized in that a region having a light receiving sensitivity is arranged offset from the center of the element.

[0009]

According to the present invention, the electrodes are formed on the light-receiving surface side so as to be symmetrical with respect to the center of the pellet having light-sensitivity arranged in the lens of the light-receiving element, or the center of gravity of the light-sensitivity of the pellet is closer to the center of the pellet. If they are misaligned, when the pellets are placed in the light-receiving element lens in advance, the light-sensitivity center of gravity is placed in the center of the element. Since the center of gravity is aligned with the optical axis and sufficient sensor sensitivity is obtained, and the sensor sensitivity does not change even when the sensor is rotated, the sensor mounting work can be facilitated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a light receiving element of the present invention. In the light receiving element 3, a phototransistor element pellet 3a is placed on a table 3c in the lens, and an electrode 3b is formed on the light receiving surface side thereof. Of course, electrodes are also formed on the back side of the pellets, and the lead wires connected to the electrodes on both the front and back sides are taken out to the outside of the element. The electrode 3b has a rectangular pellet 3a as shown in FIG.
It is placed in the center of and is symmetrical with respect to the center.
Although the electrode 3b has no sensitivity to light, the center of gravity of the region having the photosensitivity excluding the electrode is at the center of the element, and therefore the center of the light-receiving sensitivity does not change even when the element is rotated. If such a light receiving element is used, the center of light receiving sensitivity coincides with the optical axis and the maximum sensor sensitivity can be obtained simply by mounting the ADC sensor straight on the photosensitive material.

FIG. 2 is a diagram showing another embodiment of the present invention. FIG. 2 (a) shows an electrode 3b having the same width formed on the right and left sides of a rectangular pellet 3a, and FIG. 2 (b) shows an electrode formed on the four sides of a rectangular pellet. Also, since the electrode is formed symmetrically with respect to the center of the pellet, the center of gravity of the photosensitivity is at the center of the pellet.

2 (c) and 2 (d) show the case where a circular pellet is used. As shown in FIG. 2 (c), an electrode 3b is formed at the center of the pellet, and as shown in FIG. 2 (d). By thus forming the electrode 3b on the peripheral portion thereof, the center of light-receiving sensitivity can be set to the center of the pellet in any case.

FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 3A shows a case in which the electrode 3b of the pellet 3a is not formed in the center, and when such a pellet is arranged in the light receiving element lens, the pellet 3a is shifted from the center so that the light receiving sensitivity center of gravity is the element 3 Try to be the center of.

When adjustment in one direction, for example, left and right, is allowed, the pellet of FIG. 3A is rotated by 45 ° to center the sensitivity center of gravity in the vertical direction, and by adjusting the left and right positions. The light-sensitivity center of gravity is made to coincide with the center of the element 3. Further, as shown in FIG. 3B, the pellet 3a is rotated by 90 degrees, 180 degrees, or 270 degrees,
As in the case of (a), the positions are shifted so that the center of gravity of the photosensitivity is at the center of the element 3.

[0015]

As described above, according to the present invention, since the center of gravity of the light receiving sensitivity can be the center of the light receiving element, the ADC
Optimal sensor sensitivity can be obtained simply by arranging the sensor in a straight line with respect to the surface of the light-sensitive material. Also, since the center of gravity of the photosensitivity is at the center of the element, the sensor can be placed in any direction by rotating the photosensor. The sensitivity does not change, and the installation work can be facilitated.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing an example in which an electrode is not located at the center of a pellet.

FIG. 4 is a diagram showing an ADC sensor.

FIG. 5 is a diagram showing variations in sensor sensitivity depending on directions.

[Explanation of symbols]

 3 light receiving element 3a phototransistor 3b electrode 3c unit

Front page continued (72) Inventor Masayuki Kaneda 2274 Hongo, Ebina City, Kanagawa Fuji Zero Tux Co., Ltd.Ebina Works (72) Inventor Yasuhiro Fujikata 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Horikawa-cho, Ltd. (72) Inventor Matsumi Ichimura 580-1 Horikawa-cho, Sachi-ku, Kawasaki-shi, Kanagawa Stock Company Toshiba Semiconductor System Technology Center

Claims (3)

[Claims] 1. A recording comprising a light-emitting element for irradiating light to a sensitive material and a light-receiving element for receiving reflected light from the sensitive material, wherein optical density on the sensitive material is determined by the amount of received light to perform density control. In the apparatus, the density detecting device of the recording device, wherein the light receiving element is configured such that a light receiving sensitivity center of gravity is located at the center of the element. 2. The density detection of the recording apparatus according to claim 1, wherein the light receiving element has electrodes formed on the light receiving surface side symmetrical with respect to the center of the region having light receiving sensitivity. apparatus. 3. The density detecting device for a recording apparatus according to claim 1, wherein the light receiving element is arranged such that a region having the light receiving sensitivity is displaced from the element center so that the light receiving sensitivity center of gravity is at the element center. .