JPH04251274A - Concentration detecting device on wet type image forming device - Google Patents

Abstract

PURPOSE:To provide a concentration detecting device always carrying out an accurate concentration detection by using the light of an optimum arbitrary wavelength for each color of color developing liquids. CONSTITUTION:An incandescent lamp 1 emitting the light of the wavelength of, at least, 400-700nm, and a prism 4 resolving the light at every wavelengths, are straightly arranged, and further, in front of them, a photodetector is arranged. The light emitted from the incandescent lamp 1 is split by the prism 4, radiated into the developing liquid, and reaches the photodetector 5. The light received by the photodetector 5 is converted into an electrical signal, to measure the concentration of the developing liquid. At this time, the wavelength of the light received by the photodetector 5 is set at an optimum wavelength that transmissivity is most changeable with respect to a change in the concentration of the developing liquid 10, by adjusting the arranging angle of the prism or the arranging position of the photodetector 5.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a wet image forming method in which a photoreceptor or photosensitive paper is charged and exposed to form an electrostatic latent image, and then a developer is supplied to the electrostatic latent image to obtain a visible image. The present invention relates to a forming device, and more particularly to a concentration detection device for detecting the concentration of liquid toner.

0002

2. Description of the Related Art Conventionally, this type of concentration detection device has been constructed from a pair of light emitting element 1 and light receiving element 5, as shown in FIG. It is fixed to the mounting member 21 and the mounting member 22. Then, the light emitted from the light emitting element 1 is transmitted into the liquid toner 10, and the light is received by the light receiving element 5, and the density is detected based on the magnitude of the output of the light receiving element 5, that is, the light transmittance of the liquid toner 5. As a bookmark, a near-infrared LED or the like has usually been used as the light emitting element 1.

0003

[Problems to be Solved by the Invention] However, when using color developers, there is a problem that when near-infrared light is used, depending on the color, the change in the amount of transmitted light depending on the toner density is small, making it impossible to accurately detect the density. . Another possibility is to use three-color LEDs: red, green, and blue, but blue LEDs are expensive and have low output, so they are not practical. Furthermore, with the above LED, it was not possible to select an arbitrary wavelength that was optimal for each developer.

The present invention has been made in order to solve the above-mentioned problems, and provides a wet image method that uses light of arbitrary wavelengths that are optimal for each color of a color developer to always perform accurate density detection. An object of the present invention is to provide a concentration detection device in a forming apparatus.

[0005]

[Means for Solving the Problems] In order to achieve this object, the concentration detection device of the present invention has at least 400 to 700
a light emitting means that generates light with a wavelength of 0 nm; a wavelength decomposition means that decomposes the light generated from the light emitting means into each wavelength;
A light receiving means is provided for receiving the light decomposed by the wavelength decomposing means and converting it into an electrical signal.

[0006]

[Operation] In the density detection device in the wet image forming apparatus of the present invention having the above-mentioned configuration, the light emitting means has at least 40
Generates light with a wavelength of 0 to 700 nm, the wavelength decomposition means decomposes the light generated from the light emitting means into wavelengths, and the light receiving means receives the light decomposed by the wavelength decomposition means and converts it into an electrical signal. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of the concentration detection device of the present invention.

A light bulb 1 which is a light emitting means that generates light with a wavelength of at least 400 to 700 nm, a slit plate 2 which cuts unnecessary height, and a prism 4 which is a wavelength decomposition means which decomposes light into wavelengths are arranged in a straight line. and a light receiving element is placed in front of it.

FIG. 2 shows the transmittance of each developer.
FIG. 2(a) shows a yellow developer, FIG. 2(b) shows a magenta developer, and FIG. 2(c) shows a cyan developer. This is a fairly ideal spectral transmittance of a developer, and the actual spectral transmittance is slightly different. Yellow developer is 400-500nm, magenta developer is 500-600nm, cyan developer is 600-70nm.
At a wavelength of 0 nm, the transmittance changes most with respect to changes in developer concentration.

Next, the concentration detection device of this embodiment will be explained using FIGS. 1 and 2.

Light generated from the light bulb 1, which is the light emitting means, passes through the slit groove 3 of the slit plate 2 and reaches the prism 4. The light is decomposed by the prism 4 and emitted from the wall surface 6a of the detection housing 6 into the developer 10. A portion of the light emitted into the developer 10 is absorbed by the developer and the light is emitted from the wall 6a of the detection housing 6. The light enters from the wall surface 6b and reaches the light receiving element 5. The light received by the light receiving element 5 is converted into an electrical signal and sent to a detection circuit (not shown), where the concentration of the developer is measured.

The wavelength of the light received by the light receiving element 5 is as follows:
By adjusting the arrangement angle of the prism 4 or the arrangement position of the light-receiving element 5, the optimal wavelength is set at which the transmittance changes most with respect to changes in the concentration of the developer 10.

FIG. 1 is a diagram for measuring the toner concentration of a yellow developer, and the light receiving element 5 receives blue light. When detecting the concentration of developer of another color, by changing the arrangement angle of the prism 4 or the arrangement position of the light-receiving element 5, the light received by the light-receiving element 5 can be changed to red light or green light to achieve optimal conditions. It is possible to perform concentration detection at

Further, changes in the amount of light due to dirt on the walls 6a, 6b or deterioration of the light bulb 1 can be corrected by taking the difference between when the developer is present and when the developer is not.

The present invention is not limited to the embodiments described in detail above, and various changes can be made without departing from the spirit thereof.

In this embodiment, measurement using wavelengths having a certain width has been described, but it is also possible to provide a slit plate in front of the prism 4 and perform detection at a single wavelength. Furthermore, the single wavelength measurement was performed at 400 to 700
By performing the detection for all wavelengths up to nm, it is possible to detect the concentration of the developer with higher accuracy.

Further, in this embodiment, the light bulb 1, slit plate 2, prism 4, and light receiving element 5 are arranged in the detection housing 6, but they may be arranged in the developer 10 as they are.

Although a prism is used as the wavelength decomposition means, filters corresponding to each color may also be used.

[0020]

[Effect of the invention] As is clear from the detailed description above,
According to the present invention, it is possible to provide a liquid concentration detection device for a wet image forming apparatus that always performs accurate concentration detection using light of an arbitrary wavelength that is optimal for each color of a color developer.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a concentration detection device of the present invention.

FIG. 2 is a diagram showing the spectral transmittance of each color developer.

FIG. 3 is a schematic diagram of a conventional concentration detection device.

[Explanation of symbols]

1 Light bulb 2 Slit plate 3 Slit groove 4 Prism 5 Photo receiving element 6 Detection housing 10 Developer solution

Claims (1)

[Claims] 1. A density detection device in a wet image forming apparatus that forms an electrostatic latent image by charging and exposing a photoreceptor or photosensitive paper, and then supplies a developer to the electrostatic latent image to obtain a visible image. A light emitting means for generating light with a wavelength of at least 400 to 700 nm, a wavelength decomposing means for decomposing the light emitted from the light emitting means into wavelengths, and receiving the light decomposed by the wavelength decomposing means to generate an electrical signal. What is claimed is: 1. A density detection device for a wet image forming apparatus, comprising a light receiving means for converting light into a light receiving device.