JPH0437989B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrostatic recording device, and particularly to an electrostatic recording device in which a plurality of types of toner of different colors are used to develop an electrostatic image formed on an image carrier surface. [Prior Art] Conventionally, the electrostatic recording device as described above is known as a color image recording device or a recording device capable of recording with either red or black toner. On the other hand, as a means for detecting whether or not the recording paper to which the toner image has been transferred from the image carrier surface has been separated from the image carrier, a light emitting element is installed on the surface of the image carrier at a position where separation of the recording paper has been completed. Twisting the light,
A jam detection means is also known in which the amount of reflected light is detected by a light receiving element, and if the amount of reflected light is large, it is determined that separation has not occurred. When such a jam detection means is used in an electrostatic recording device as described above, the amount of reflected light increases depending on the color of the toner, and it may be determined that the recording paper has not been separated even though it has been separated. arise. In order to prevent this, the irradiation light and the light receiving element may be changed depending on the type of toner color, but this would complicate the apparatus. [Object of the Invention] The present invention has been made in order to solve the above-mentioned problems, and provides a method for detecting the presence or absence of a jam using a single type of irradiation light and a light-receiving element. The present invention provides an electrostatic recording device using. [Structure of the Invention] The present invention provides an electrostatic recording device capable of forming a chromatic image, in which it is possible to determine whether or not a recording paper to which a toner image has been transferred from an image carrier is separated from the image carrier. In order to detect the reflected light from the image carrier on which the toner image is formed, a detection means is provided on the downstream side of the transfer means, and the spectral reflection characteristics of the toner forming the image are provided as a light source for producing the reflected light. The present invention is an electrostatic recording device characterized by using a light source that emits light that does not substantially include a high reflection region, and with this configuration, the above object is achieved. [Example] The present invention will be explained below using illustrated examples. FIG. 1 is a schematic configuration diagram showing an example of the electrostatic recording device of the present invention, FIG. 2 is a sectional view of a reflected light detection device on the surface of an image carrier, and FIG. 3 is a diagram showing the relationship between the wavelength of irradiation light and the reflectance of color toner. A graph showing the relationship, and FIG. 4 is a circuit diagram of the reflected light detection device. The electrostatic recording device shown in FIG.
The image is projected onto the surface of the image carrier 6 rotating in the direction of the arrow by a scanning optical system consisting of an exposure lamp 2, mirrors 3 and 4, an exposure slit 5, etc., and before that the image carrier 6 is Since the surface of the electrophotographic photoreceptor is uniformly charged, an electrostatic image is formed by projection, and each electrostatic image is processed by a developing device using color toners such as blue, red, and sepia. Developed by any one of 8 to 10,
The developed toner image is transferred from the recording paper supply unit 11 via the conveyors 12 and 13 to the recording paper P, which is brought into contact with the surface of the image carrier 6 by the transfer device 14.
The transferred recording paper P is transferred to the image carrier 6 by the separator 15 and the separation blade 16.
The toner image is separated from the surface and placed on a conveyor 17, and conveyed by the conveyor 17 to a fixing device 18, where the toner image is fixed and discharged outside the machine.
Then, the surface of the image carrier 6 to which the toner image has been transferred is neutralized by a static eliminator 19, and residual toner is removed by a cleaning device 20, making it ready for the next image formation. This recording apparatus is also provided with a detecting device 21 as shown in FIG. 2 behind the separating blade 16 for detecting whether or not the recording paper P has been separated without any trouble. This detection device 21 irradiates the surface of the image carrier 6 with a light emitting element 21a such as an LED, and detects the intensity of the reflected light using a light receiving element 21b such as a phototransistor. The light-emitting element 210a is designed to emit light of a wavelength having a low reflectance due to the color toner used in the developing devices 8 to 10, and the light-receiving element 21b is designed to have high sensitivity to light of that wavelength. Thereby, even if the electrostatic image is developed by any of the developing devices 8 to 10, it is possible to prevent the misunderstanding that the recording paper P has not been separated due to the reflected light of the toner image. The detection device 21 accurately detects that the recording paper P has not actually been separated. To explain this point using Figure 3, blue,
Since the reflectance curves of red and sepia color toners are shown as dotted lines, solid lines, and dashed-dotted lines, respectively, it is mistakenly assumed that the irradiated light has a wavelength of around 460 nm and that the separation was not done due to the light reflected by the blue toner. In addition, red toner with a wavelength longer than 660 nm can be mistaken for reflected light, and toner with a wavelength longer than 700 nm can be mistaken for any color toner. happens. Therefore, blue is applied to developing units 8 to 10.
When red and sepia color toners are used, the light emitting element 21a and the light receiving element 21b are
A device that emits light of 420 nm or less or 500 to 660 nm, and a device that is highly sensitive to the irradiated light. Table 1 shows the experimental results of whether or not jam detection was performed accurately with respect to the wavelength of irradiation light and the color toners of blue, red, and sepia.

〔Effect of the invention〕

In the electrostatic recording device of the present invention, it is possible to accurately determine whether or not the recording paper has been separated from the image carrier without being affected by the colors of multiple color toners used in one detection device. This provides an excellent effect in that it can be detected.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of the electrostatic recording device of the present invention, FIG. 2 is a sectional view of a reflected light detection device on the surface of an image carrier, and FIG. 3 is a diagram showing the relationship between the wavelength of irradiation light and the reflectance of color toner. A graph showing the relationship, and FIG. 4 is a circuit diagram of the reflected light detection device. 6... Image carrier, 8-10... Developing device, 15...
... Separator, 16 ... Separation blade, 21 ... Detection device, 21a ... Light emitting element, 21b ... Light receiving element, 22 ... Operational amplifier, 23 ... Comparator, Vcc ... Power supply, R ₁ to R ₆ ... resistance.

Claims (1)

[Scope of Claims] 1. In an electrostatic recording device capable of forming a chromatic image, it is detected whether a recording paper onto which a toner image has been transferred from an image carrier is separated from the image carrier. Therefore, a detection means for detecting the reflected light from the image carrier on which the toner image is formed is provided downstream of the transfer means, and a detection means for detecting the reflected light from the image carrier on which the toner image is formed is provided, and a detection means is provided on the downstream side of the transfer means. An electrostatic recording device characterized by using a light source that emits light that does not substantially include a reflective region. 2. The chromatic image is a plurality of color images each having a different color, and the light source that emits light that does not substantially include a high reflection region due to the spectral reflection characteristics of any toner forming each color image is used. An electrostatic recording device according to claim 1, characterized in that: