JPH0593689A - Detecting device of density of recording apparatus - Google Patents

Abstract

PURPOSE:To improve an S/N ratio and thereby to detect the density of toner with high precision by reducing a diffused light component contained in a detected light, as much as possible. CONSTITUTION:Optical axes are regulated by providing a masking member 8 on a seal member surface 5 provided in front of pinholes 6 and 7. The position of the masking member 8 is defined by a projecting or recessed part formed in the seal member 5 beforehand and the masking member is provided in the part by coating or the like. The effect of refraction and diffusion in the seal member 5 is removed and thereby an S/N ratio can be improved.

Description

Detailed Description of the Invention

[0001]

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

In order to control the density as described above, the present applicant has already proposed an ADC (Automatic Density Cont) as shown in FIG.
rol) sensor is proposed. In this ADC sensor, a light emitting element 2 and a light receiving element 3 are resin-sealed in a case 4, pinholes 6 and 7 are formed, and a seal member 5 made of glass or the like is provided on the front surface to prevent toner, paper dust or the like. The leads 11 and 12 are respectively connected to the light emitting element and the light receiving element so as not to enter the pinhole, and the leads 13 are taken out 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 light reflected from the surface of the photosensitive material is received by the light receiving element 3 through the pinhole 7. .. Toner on which the electrostatic latent image is developed is attached to the surface of the photosensitive material, and the toner has a light absorbing property.

For example, FIG. 4 shows the ratio of the toner density of each color and the amount of reflected light when light of 630 nm is irradiated. The direct reflected lights of Red, Brown and Green are characteristic D, E and F, respectively. As shown in, the toner concentration and the amount of reflected light are in inverse proportion to each other. Therefore, the toner concentration can be detected by detecting the amount of reflected light from the surface of the photosensitive material.

[0006]

Since the light emitting element emits surface light, it spreads by at least 15 degrees or more at a half value angle. Therefore, as shown in FIG. 3, a pinhole 6 is provided to narrow the beam. ing. Further, the surface of the photosensitive material is not smooth due to the toner particles, and when light is irradiated onto the surface, irregular reflection occurs. Therefore, in addition to the direct reflected light from the target position on the optical axis, the diffused light diffusely reflected by the toner particles at other positions is included in the detected light, which lowers the toner concentration detection accuracy. Cause of. The ratio between the toner density of this diffused light and the amount of reflected light is as shown in FIG.
It becomes like each characteristic A, B, C for own and Green,
It increases according to the toner density, and tends to saturate above a predetermined density. When such an amount of diffused light becomes approximately the same as the amount of directly reflected light, density detection becomes impossible. Therefore, FIG.
As shown in FIG. 5, the light beam is narrowed down by the pinholes 6 and 7, the diffused light component is reduced as much as possible, and the toner density is detected by detecting only the direct reflected light.

By the way, as shown in FIG. 3, a seal member 5 is provided so that toner, paper dust, etc., do not enter the front surface of the pinhole.
Is provided and the seal member 5 has a constant thickness, so that refraction and diffusion of light occur at this portion. Therefore, for example, in the light emitted from the pinhole 6, a component deviated from the optical axis is generated in the seal member, and the pinhole 7
Then, there is a problem that light off the optical axis is detected through a pinhole by refraction or diffusion,
There is a problem that this lowers the S / N ratio.

The present invention is intended to solve the above-mentioned problems, and suppresses the diffused light component contained in the detected light as much as possible.
An object of the present invention is to provide a density detecting device for a recording device, which can improve the / N ratio and detect the toner density with high accuracy.

[0009]

According to the present invention, a light emitting element for irradiating light to a sensitive material through a pinhole, a light receiving element for receiving reflected light from the sensitive material through the pinhole, and a light receiving element provided on the front surface of the pinhole. In a recording apparatus including a seal member, the optical density on the photosensitive material is detected by the amount of received light to control the density, a masking member for regulating the optical axis is provided on the seal member, and the masking member is It is characterized in that it is provided in a convex portion or a concave portion formed in the seal member.

[0010]

According to the present invention, a masking member is provided on the seal member surface provided on the front surface of the pinhole to regulate the optical axis, and the influence of refraction and diffusion in the seal member is suppressed as much as possible, and the diffused light component from the photosensitive material is suppressed as much as possible. The S / N ratio is improved to detect the toner density with high accuracy. Further, since the convex portion or the concave portion is formed on the sealing member in advance and the masking member is provided on the portion by coating or the like, accurate positioning becomes possible and highly accurate detection can be performed.

[0011]

FIG. 1 is a diagram showing an embodiment of the present invention. In the figure, the same numbers as those in FIG. 3 indicate the same contents. In the present invention, a masking member 8 is provided on the front surface of a transparent sealing member such as glass, polycarbonate, acrylic or the like provided on the front side of the pinhole by coating or adhering in order to regulate the optical axis. is there. For this masking member, it enters the seal member 5 through the pinhole 6,
Light that is refracted or diffused and deviated from the optical axis is absorbed by the manking member 8, and only the thin beam along the optical axis is applied to the photosensitive material. Further, diffused light and the like deviated from the optical axis due to reflected light from the photosensitive material is absorbed by the masking member 8 and is not detected, and light refracted or diffused in the seal member 5 is restricted by the pinhole 7. Therefore, it does not affect the detection. Therefore, the influence of refraction and diffusion in the seal member 5 can be eliminated.

It should be noted that the smaller the hole diameter of the pinhole and the longer it is, the more the influence of diffused light is eliminated, and the sensitivity can be increased. However, the light amount is reduced, and therefore the pinhole has a relationship between the required light amount and the allowable sensitivity. Be sure to determine the hole diameter and length. In this embodiment, the pinhole length is 2 mm and the diameter is 1 m.
m, and because the photoconductor drum is spinning, the wind is wiping and the toner is flying in that part, so there should be a gap of about 5 mm between the photoconductor and the detection. Is desirable.

By the way, if the masking member 8 shown in FIG. 1 is displaced, the optical axis is displaced, and as a result, the absolute light amount is reduced. Therefore, in that case, it is necessary to tilt the sensor to select the position with the highest detection sensitivity, but the operation is extremely troublesome. Therefore, as shown in FIG. 2, a convex portion or a concave portion is formed on the seal member 5 by a mold or the like as shown in FIG. 2A, and the masking member 8 is formed on the portion by coating or bonding. If this sealing member is attached to the case 4, the masking member 8 will not be displaced and the pinhole hole can always be formed accurately on the optical path.

[0014]

As described above, according to the present invention, the influence of diffused light deviated from the optical axis can be removed as much as possible, the sensitivity of concentration detection can be increased, and the displacement of the masking member can be eliminated. It becomes possible to always form a pinhole window at an accurate position.

[Brief description of drawings]

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

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

FIG. 3 is a diagram showing a conventional ADC sensor.

FIG. 4 is a diagram showing a ratio between the toner density of each color and the amount of reflected light when irradiated with light of 630 nm.

[Explanation of symbols]

 1 Concentration sensor 2 Light emitting element 3 Light receiving element 4 Case 5 Sealing member 6,7 Pinhole 8 Masking member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location G03G 15/06 101 7818-2H 15/08 115 9222-2H (72) Inventor Toru Yoshida Ebina Kanagawa 2274, Hongo, Ichi, Fuji Era-Tux Co., Ltd.Ebina Works (72) Inventor Yasuhiro Fujikata 72 Horikawa-cho, Kawasaki-shi, Kanagawa Prefecture 72 Horikawa-cho Factory, Toshiba Corporation (72) Inventor Matsumi Ichi-mura, Kawasaki-shi, Kanagawa Prefecture 580-1 Horikawa-cho, Toshiba Semiconductor Systems Technology Center Co., Ltd. (72) Inventor Tsuguo Uchino 1-10-1 Shimoitsutsu-cho, Kokurakita-ku, Kitakyushu, Fukuoka Prefecture Toshiba Kitakyushu Factory

Claims (2)

[Claims] 1. A light-receiving element comprising: a light-emitting element for irradiating light on a light-sensitive material through a pinhole; a light-receiving element for receiving reflected light from the light-sensitive material through the pinhole; and a seal member provided in front of the pinhole. A density detecting apparatus for a recording apparatus, wherein a masking member for controlling an optical axis is provided on the seal member in the recording apparatus for detecting the optical density on the photosensitive material and controlling the density. 2. The density detecting device for a recording apparatus according to claim 1, wherein the masking member is provided on a convex portion or a concave portion formed on the seal member.