JPH05142888A - Image forming device - Google Patents

Abstract

PURPOSE:To inform timing to clean a contact glass, mirror, etc., or to control factors affecting image forming density by detecting stained state of the contact glass and mirror, etc. CONSTITUTION:An image forming device is provided with an original presence judging means 2 for judging presence of an original on a contact glass 1, a stain detecting means 3 arranged under the contact glass 2 for radiating light from under the contract glass 1 to the top of it to be reflected by a closed original pusher 4 and for detecting the light returned to under the contact glass 1 when the original presence judging means 2 judges no presence of the original, and a control means 9 for controlling factors affecting image forming density or for controlling display of detection results.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a contact glass on which a document is placed.

[0002]

2. Description of the Related Art Conventionally, a main body of a copying machine is provided with a contact glass on which an original is placed. The lower side of the contact glass is composed of an optical unit, and in the optical unit, an exposure lamp for shining light on the original, a mirror for guiding the light of the exposure lamp reflected and returned from the original to a lens for imaging, Further, a mirror and the like for irradiating the photosensitive layer with the original image picked up by the lens are arranged.

When a document is placed on the contact glass and a copy operation is performed, the exposure lamp emits light and moves while exposing the document from one end to the other through the contact glass. The light reflected and returned from the document is incident on the lens by a mirror that moves integrally with the exposure lamp and a pair of mirrors that move in the same direction at half the speed of the exposure lamp. The light incident on the lens becomes a document image, and the document image is guided to the photosensitive drum side by a fixed mirror, and an electrostatic latent image of the document image is formed on the photosensitive layer. After that, development processing, transfer to copy paper, fixing of toner, and the like are performed, and the copy operation ends.

[0004]

While using the copying machine, contact glass, dust, toner, etc.
If the mirror or the like becomes dirty, less light will reach the photosensitive layer, resulting in poor copy quality. In order to prevent this, it is necessary to clean the contact glass, the mirror, etc., and conventionally, the contact glass, the mirror, etc. were cleaned at the same time as the maintenance of the copying machine main body.

However, according to the above method, the contact glass, the contact glass, etc.
Depending on the usage environment and other conditions, the contact glass, mirror, etc. must be kept dirty until the maintenance of the copier body is complete, because the mirrors etc. have different stains. In that case, to maintain the copy quality. There is a problem that the operator has to manually adjust the exposure amount each time.

In consideration of the above-mentioned conventional problems, the present invention detects the dirt state of the contact glass, the mirror, etc. to notify the cleaning time of the contact glass, the mirror, etc., or influence the image forming density. An object of the present invention is to provide an image forming apparatus capable of controlling a given factor.

[0007]

SUMMARY OF THE INVENTION According to the present invention, in an image forming apparatus having a contact glass for placing an original, an original presence / absence determining means for determining the presence / absence of an original on the contact glass, and a contact glass Placed on the lower side,
When the document presence / absence determining unit determines that there is no document, light is emitted from the lower side to the upper side of the contact glass, reflected by the document retainer closed on the contact glass, and transmitted through the contact glass to make contact. Based on the detection result of the stain detection unit and the stain detection unit that detects the light returned to the lower side of the glass or the light reflected by the mirror for exposing the light to the photosensitive surface, The image forming apparatus includes a control unit that controls an influencing factor or controls the display of the detection result.

[0008]

According to the present invention, the document presence / absence determining means determines the presence / absence of a document on the contact glass, and when the document presence / absence determining means determines that there is no document, the stain detecting means determines the contact glass from the lower side to the upper side. The light reflected by the document holder closed on the contact glass, transmitted through the contact glass and returned to the lower side of the contact glass, or the light for further exposing the photosensitive surface. Detecting the light reflected by the mirror, the control unit controls the factor that affects the image forming density or controls the display of the detection result based on the detection result of the stain detection unit.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a sectional view of a copying machine according to an embodiment of the present invention. That is, the contact glass 1 for placing a document on the upper side is fitted in the main body of the copying machine as an image forming apparatus, and the document holder 4 for pressing the document placed on the contact glass 1 is opened and closed at the end. Is linked to. The lower side of the contact glass 1 is composed of an optical unit 20. In the optical unit 20, an exposure lamp 6 that exposes a document to light, and an exposure lamp 6 that changes the direction of light reflected from the document are integrated. A mirror 7a, a pair of mirrors 7b and 7c for guiding light coming from the mirror 7a to a lens 8 for imaging, a mirror 7d for projecting an original image formed by the lens 8 on a photosensitive surface, and the like are provided.

Further, a document presence / absence determining means 2 for determining the presence / absence of a document on the contact glass 1 and a stain detecting means 3 for detecting stains on the inner surface of the contact glass 1 are arranged at a position close to and below the contact glass 1. Has been done. Each of the document presence / absence determining means 2 and the dirt detecting means 3 has a sensor portion including a light emitting portion and a light receiving portion, and the document presence / absence determining means 2 is connected to the dirt detecting means 3 and the dirt detecting means 3
Is connected to the control means 9 for controlling the display of the dirty state. Further, near the lens 8, an AE sensor 5 for detecting the document density for automatically adjusting the image density is arranged. On the other hand, an open / close detection switch 21 for detecting the open / closed state of the document retainer 4 is provided on the upper side of the main body near the end of the contact glass 1 to determine the presence / absence of a document.

Below the optical unit 20, a photosensitive drum 10 for forming an electrostatic latent image on a photosensitive layer on the surface thereof by a sent original image, and a main charging electrode for main charging the photosensitive layer of the photosensitive drum 10. 11, a developing device 12 for developing the electrostatic latent image formed on the photosensitive layer, a developed toner image is transferred to a copy sheet, and the copy sheet is transferred to the photosensitive drum 10.
A transfer / separation device 13 that separates the copy paper, a conveyor belt 14 that conveys the copied copy paper, a fixing device 15 that fixes the toner image of the copy paper conveyed by the conveyor belt 14, and the like are provided, and an original image is formed on the copy paper. So that it can be copied.

Next, the operation of the above embodiment will be described with reference to FIGS.

First, the copying machine main body is turned on, and if the document retainer 4 is closed, it is once opened and then closed again. During the operation of closing the document retainer 4, the document retainer 4 operates the open / close detection switch 21 so that the document presence / absence determining means 2 becomes operable. When the document retainer 4 is completely opened or closed, the document presence / absence determining unit 2 is configured not to start the determination operation (step S1). The light emitting unit of the document presence / absence determining unit 2 determines the presence / absence of a document by irradiating the contact glass 1 side with light and detecting whether the reflected light returns by the light receiving unit. If it is determined that the document is present, the normal copy operation is started, and if it is determined that the document is absent, the stain detecting means 3 is determined based on the result.
Starts operating (step S2).

The operation of the dirt detecting means 3 is started by pressing the document holder 4
Is performed after the light is closed, and the light emitting portion irradiates the contact glass 1 side with the light for detection, the light is transmitted through the contact glass 1 and reflected by the document holder 4, and the light receiving portion receives the light transmitted through the contact glass 1 again. It is detected (step S3). The dirt detection unit 3 is set in advance with a reference level for judging the dirt state, and compares the detected light level with the reference level (step S4). If there is no abnormality as a result, it is normal. When the copy operation is started and the level is lower than the reference level, on the contrary, it is determined that the inner surface of the contact glass 1 is dirty, and the detection result is output to the control means 9. Upon receiving the detection result, the control means 9 displays on the display panel or the like that maintenance such as cleaning of the inner surface of the contact glass 1 is necessary (step S5).
After that, the normal copy operation is started.

FIG. 3A shows the above functions realized by software using a microcomputer. Further, a document size detecting sensor which has been conventionally used is applied to the sensor portion of the dirt detecting means 3. The document presence / absence detection sensor is the same as the sensor unit of the document presence / absence determining means 2 of the above-described embodiment. Therefore, the microcomputer has various functions such as the determination function of the document presence / absence determination unit 2, the determination function of the stain detection unit 3, the control unit, and the display unit of the keyboard has the display function. FIG. 3B is a flow chart showing the operation, and the step of detecting the document size detecting sensor level corresponds to the step of detecting the stain state (step S3) in the above embodiment. In each of FIGS. 3B to 8B, the step of presence / absence determination enabled (step S1) shown in FIG. 2 is omitted.

In the above embodiment, the dirt detecting means 3 is configured to detect the dirt on the contact glass 1 only, but instead of this, for example, the sensor portion of the dirt detecting means 3 is located near the lens 8. By placing the mirror 7a,
You may comprise so that the dirt of 7b and 7c may also be detected. In this case, as shown in FIG. 6A, FIG. 7A, and FIG. 8A, the AE sensor 5 for detecting the document density is provided in the light receiving portion.
Of course, it is also possible to use an exposure lamp for the light emitting portion. Flow charts of the operation at this time are shown in FIG. 6 (b), FIG. 7 (b), and FIG.
It shows in (b). Alternatively, in order to detect the dirt of the lens 8 as well, the sensor unit of the dirt detecting means 3 is attached to the lens 8
It may be arranged on the rear side (right side in the drawing).

Further, in the above-mentioned embodiment, the control means 9 indicates that the maintenance is necessary when the dirt is detected, but the present invention is not limited to this, and FIG. 4 (a), FIG. 5 (a), FIG. 7A and FIG. 8A, the decrease in the exposure amount due to stains may be corrected by controlling the voltage of the exposure lamp and the surface potential of the photosensitive surface. The flow chart of the operation at this time is shown in FIG. 4 (b), FIG. 5 (b), and FIG.
(B) and FIG.8 (b) are shown. Alternatively, of course, some or all of them may be controlled at the same time.

In the above embodiment, the document presence / absence determining means 2 and the stain detecting means 3 are separately configured, but the invention is not limited to this, and they may be integrally configured. The same function may be added to the detection device.

Further, in the above embodiment, the sensor section of the document presence / absence determining means 2 and the sensor section of the dirt detecting means 3 are separately provided, but the present invention is not limited to this, and one sensor section is also used as each sensor section. May be.

[0021]

As is apparent from the above description, according to the present invention, the document presence / absence determining means for determining the presence / absence of the document on the contact glass and the document presence / absence determining means arranged under the contact glass are provided. When it is determined that there is no document, light is emitted from the lower side to the upper side of the contact glass, reflected by the document holder closed on the contact glass, transmitted through the contact glass, and returned to the lower side of the contact glass. Stain detecting means for detecting the reflected light or the light reflected by a mirror for further exposing the light to the photosensitive surface, and controlling the factor affecting the image forming density based on the detection result of the stain detecting means Or with a control means for controlling the display of the detection result,
It has an advantage that it is possible to inform when to clean the contact glass, the mirror, etc., or to control a factor affecting the image forming density.

[Brief description of drawings]

FIG. 1 is a sectional view of a copying machine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 (a) is a schematic block diagram for displaying a detection result of a dirty state of another embodiment, and FIG. 3 (b) is a flowchart of the operation.

FIG. 4A is a schematic block diagram in the case of controlling the voltage of an exposure lamp based on the detection result of the dirt state of another embodiment, and FIG. 4B is a flow chart of the operation. is there.

FIG. 5A is a schematic block diagram in the case of controlling the surface potential of the photosensitive surface based on the detection result of the dirt state of another embodiment, and FIG. 5B is a flow chart of the operation. Is.

FIG. 6A is a schematic block diagram in the case of displaying a detection result of a dirty state including a mirror of another embodiment, and FIG. 6B is a flow chart of the operation.

FIG. 7A is a schematic block diagram in the case of controlling the voltage of the exposure lamp based on the detection result of the dirt state including the mirror of another embodiment, and FIG. It is a flow chart of operation.

FIG. 8A is a schematic block diagram in the case of controlling the surface potential of a photosensitive surface based on a detection result of a dirt state including a mirror of another embodiment, and FIG. It is a flowchart of the operation.

[Explanation of symbols]

 1 Contact Glass 2 Document Existence Determining Means 3 Contamination Detection Means 4 Original Holding 5 AE Sensor 6 Exposure Lamps 7a, 7b, 7c, 7d Mirror 9 Control Means

Claims (1)

[Claims] 1. An image forming apparatus provided with a contact glass for placing an original, and an original presence / absence determining means for determining the presence / absence of the original on the contact glass,
When the document presence / absence determining unit determines that there is no document, the document pressing unit irradiates light from the lower side to the upper side of the contact glass and closes the contact glass. Reflected by
Contamination detection means for detecting the light transmitted through the contact glass and returned to the lower side of the contact glass, or the light reflected by a mirror for exposing the light to the photosensitive surface, and the contamination detection means. An image forming apparatus, comprising: a control unit that controls a factor that affects the image forming density or controls the display of the detection result based on the detection result.