JPH03139629A - Image forming device - Google Patents

Abstract

PURPOSE:To realize the adjustment of light quantity and the automatic adjustment of density with the aid of one sensor and to eliminate a moving type reflector which switches an optical path by providing a light quantity sensor, a diffusing plate provided to the end part of an original platen and a preliminary scanning means which detects the density of an original and setting the light quantity of a light source according to the density of the original. CONSTITUTION:An exposure device moves the original platen 5 to a scanning start position and the diffusing plate 6 attached to the original platen 5 comes above the exposure device. The diffusing plate 6 is irradiated with light from the exposure device and the reflected light is made incident on the light quantity sensor 4. Then, the light quantity of a lamp 2 is set to a fixed reference based on the value of the sensor 4. Thereafter, first scanning is executed while a shutter 10 is closed and the light reflected on the original 7 is made incident on the sensor 4. Then, the density of the original 7 is read. Next, the original platen 5 is moved to the scanning start position again and exposure is executed by opening the shutter 10 after the light of the light source 2 is adjusted to the density of the original 7 by the reflected light of the diffusing plate 6. Thus, the density of the original 7 is detected by the same action as the normal exposure action with the aid of one light quantity sensor 4. As the result, the cost of a device is restrained by simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and particularly to an image forming apparatus that determines the amount of light based on light reflected from a document.

[Conventional technology]

A conventional image forming apparatus 100 having this type of exposure device is shown in FIG. The image forming apparatus 100 includes an original table 101 and an exposure device 102 that illuminates the original table 101 below the original table 101 . The light irradiated onto the document by the exposure device 102 passes through the color matching filter 103 and the lens 104, and the optical path is rotated by 18 degrees by mirrors 105 and 106, and the light is irradiated onto the microcapsule paper 107.

On the other hand, the color developer paper 108 is supplied from the color developer paper 109, and the color developer paper 108 and the microcapsule paper 107 are sent to the pressure development section 113 in an overlapping state, and the color development paper is developed in the pressure development section 113. 109 is a heat fixing device 11
4 and is fixed.

On the other hand, the microcapsule paper 107 is
11.

Here, the exposure apparatus 102 is separately provided with a light amount detection sensor that detects the amount of light from the light source 112 and a sensor that detects the density of the document.

Initially, the light intensity of the light source 112 was detected by a light intensity detection sensor that detected the light intensity of the light source 112, and then the density of the document was detected using the detected light intensity and the image on the document table was exposed to form an image. There is.

[Problem to be solved by the invention]

However, according to the above-mentioned conventional technology, since two light quantity sensors are used, which are expensive compared to other parts,
There was a problem of high cost.

To solve this problem, an image forming apparatus has been proposed that uses a movable reflector and has an exposure device that switches and inputs lamp light and reflected light from the document to a single light amount sensor, but the configuration is complicated, Moreover, there was a problem in that the cost was high.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an exposure apparatus having a light amount detection function for detecting the light amount of a light source with one sensor and a density detection function for detecting the density of an original. An object of the present invention is to provide an image forming apparatus equipped with the following.

[Means to solve the problem]

The present invention having the above object includes an exposure device having a light source that irradiates light onto a document on a document table, and forms an image by passing reflected light from the document through a lens system and forming an image on a photoreceptor. In the forming device, a light amount sensor is installed in a position that can receive reflected light from the document but does not allow direct light from the light source to detect the light amount of the light source and the density of the document, and the exposure device is placed at the scanning start position. At some point, a preliminary scan was performed to detect the density of the document using a diffuser plate installed at the edge of the document table to allow the reflected light from the light source to enter, and a light source set to a constant reference light amount before scanning for exposure. preliminary scanning means for performing;
and a light amount setting means for setting the light source to a light amount according to the density of the document detected by preliminary scanning using reflected light from the diffuser plate.

[Effect]

In the present invention having the above configuration, a document is placed on the document table, the exposure device moves the document table to a scanning start position, and the diffusion plate attached to the document table is placed above the exposure device. Light from the exposure device is irradiated onto the diffuser plate, and the reflected light is incident on the light amount sensor. Therefore, the light amount of the lamp is set to a certain standard based on the value of the light amount sensor.

Thereafter, the first scan is performed with the shutter closed. The light intensity sensor receives reflected light from the original and reads the density of the original.

Next, the document table is moved to the scanning start position again, and the light from the light source is adjusted to the density of the document by the light reflected by the diffuser plate.

Thereafter, the shutter is opened and exposure is performed in the direction of the arrow.

In this way, the density of the document can be detected using a single light amount sensor in an operation similar to a normal exposure operation, and the cost can be reduced with a simple configuration.

〔Example〕

Hereinafter, the present invention will be explained based on an illustrated embodiment. FIG. 1 shows an image exposure device of an image forming apparatus according to the present invention.

The image exposure apparatus has a lamp house 1 in the shape of a rectangular parallelepiped.

A lamp house 1 includes a lamp 2 as a light source.

A reflecting mirror 3b is provided around the lamp 2 to irradiate light from the lamp 2 onto a mirror 3a.

On the other hand, a light amount sensor 4 is arranged at the bottom of the lamp house 1. At the bottom and top of the lamp house 1, there are upper slits 1 through which the light from the lamp 2 is irradiated onto the document 7 and the reflected light passes through.
a and a bottom slit 1b.

A movable document table glass 5 is arranged above the lamp house 1, and a diffusion plate 6 is attached to the left end of the document table glass 5.

Further, a shutter 10 is provided below the bottom slit 1b provided below the lamp house 1. A lens 8 is arranged on the optical path below the shutter 10.
An exposure table 9 is arranged below.

Next, the electrical configuration of this embodiment will be explained with reference to FIG. 3. The CPU 40a and the SROM 40b.

A control circuit 40 configured mainly around a RAM 40c includes a light source section 50 that controls the light intensity of the lamp 3 via an input/output port 40d, a document table moving section 43 that moves the document table 5 in the left-right direction, and a filter 8 in the optical path. A main lamp filter unit 44 that controls the mirror to enter and exit by a predetermined amount, and a lens moving unit 4 that moves the mirror along the optical path according to the magnification.
5. A microcapsule paper transport control section 46 that transports the microcapsule paper in synchronization with the movement of the document table glass plate or stops the transport; a small diameter roller in the pressure developing device 2o that rotates at a predetermined speed or a small diameter roller; The pressure development controller 47, the suction valve 18, and the developer paper roller are rotated to convey the developer paper to the pressure development device 20, and the resist gate is closed at a predetermined time. A color developer paper transport unit 48 that moves the color developer paper into or out of the transport path, a heat fixing device control unit 49 that controls the amount of heat generated by the heat roller in the heat fixing device 20, and a color matching mode for a copy image formed on microcapsule paper. It is connected to an operating section 42 that includes setting keys (not shown) for making various settings such as selection and condition setting, a lamp light amount control section 41 that moves the optical filter 30 at a predetermined time, and a shutter control section 51.

The device configured as described above operates as follows.

The operation will be explained based on the flowchart shown in FIG.

After opening the document table cover and placing the document on the document table glass 5, the operation is started by pressing a start button (not shown).

First, the exposure device moves to the scanning start position shown in FIG. 2 (step 101). Then, the light intensity of the lamp 2 is set to a constant reference value while the light emitted from the lamp 2 is received by the light intensity sensor 4 via the diffuser plate 6 (step 102).
. At that time, the shutter 10 remains closed. Thereafter, with the shutter 10 closed, a first exposure scan is performed on the exposure table glass 5 in the direction of the arrow in FIG. 2, and a preliminary scan is performed to measure the original density (step 103).

At this time, reflected light from the original 7 enters the light amount sensor, and the density of the original 7 is read. Thereafter, the document table glass 5 is moved to the scanning start position again (step 104).

There, a diffuser plate 6 is arranged above an upper slit 1a provided at the upper part of the lamp house 2, and reflected light from the lamp 2 as a light source is incident on the light amount sensor 4 via the diffuser plate 6. Thereby, the light intensity of the lamp 2 is set according to the density of the scanned document 7 (step 105).
. Thereafter, the original 7 is exposed and scanned using the light intensity of the lamp 2 set in step 105 of the previous step. After the exposure scan, lamp 2 is turned off (step 10
t).

The subsequent operation of the image forming apparatus is as follows. That is, a color developer paper is superimposed on the formation area of the latent image formed on the microcapsule paper, and after being pressed and developed in a pressure development section, the latent image is fixed by a heat fixing device and discharged onto a tray.

〔Effect of the invention〕

As described above, the present invention includes a light amount sensor, a diffuser plate provided at the end of the document table, a preliminary scanning means for detecting the density of the document, and a light amount setting for setting the light amount of the light source according to the density of the document. Since the lamp light amount adjustment and the automatic density adjustment can be performed using one sensor, the structure is simplified because there is no need to use a movable reflector plate for switching the optical path.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of the exposure device at the initial position of the image forming apparatus of the present invention, FIG. 2 is a schematic configuration diagram of the exposure device at the scanning start position of the image forming apparatus of the present invention, and FIG. teeth,
FIG. 4 is a block diagram of the image forming apparatus of the present invention, FIG. 4 is an operation flowchart of the image forming apparatus of the present invention, and FIG. 5 is a schematic configuration diagram of the image forming apparatus of the prior art. 1...Lamp house 2...Lamp 3a...Mirror 3b...Reflector 4...Light level sensor 5...Original table glass 6...Diffusion plate 7...Original 8... Lens 9...Exposure stage 10...Shutter

Claims (1)

[Claims] In an image forming apparatus that is equipped with an exposure device that has a light source that irradiates light onto a document on a document table, and forms an image by passing reflected light from the document through a lens system and forming an image on a photoreceptor, A light sensor that detects the light amount of the light source and the density of the original is installed in a position where it can receive light but does not receive direct light from the light source, and when the exposure device is at the scanning start position, the light reflected from the light source is detected. A diffuser plate is provided at the end of the document table so that the light enters the document, a preliminary scanning means performs preliminary scanning to detect the density of the document using a light source set to a constant reference light intensity before scanning for exposure, and a shutter that blocks the optical path of the reflected light from the original, and a light amount of the light source,
An image forming apparatus comprising: a light amount setting unit that sets the amount of light using reflected light from a diffuser plate according to the density of a document detected by preliminary scanning.