JPS6135439A - Electrostatic recording device - Google Patents

Abstract

PURPOSE:To detect original size by selecting an original size detection mode throgh a switching means even after a platen cover is closed. CONSTITUTION:A beltlike yellow print part 3b is provided inside the platen cover 3 and a color sensor 24 which detects reflected light from the yellow print part 3b is equipped with detection parts 24a-24d having sensitivity to only yellow light. The yellow print part 3b and color sensor 24 constitute an original size detection part, and when the platen cover 3 is closed and a preliminary scan is made by a light source 1 for exposure, light from the light source 1 is passed through the platen glass 1 and reflected by the yellow print part 3b of the platen cover 3 to enter the color sensor 24 as yellow light. At this time, when an original of, for example, B5 is set on the platen glass 1, the reflected light is incident on the detection part 24b-24d in the color sensor 24, but no light enters the detection part 24a. Therefore, the detection parts 24b-24d detect the yellow light to detect the original of B5 being set.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic recording device in which a document is set on a platen glass, a platen cover is closed, and the size of the document is detected.

(Object of the Invention) An object of the present invention is to provide an electrostatic recording device in which the size of a document can be detected by setting the document size detection mode even after the platen cover is closed. It is to be.

(Structure of the Invention) For this purpose, in the present invention, an electrostatic recording device configured to detect the document size with the platen cover closed is provided with a switching means for selecting the document size detection mode, and the platen cover is closed. After closing, the document size detection mode is selected by the switching means to detect the document size.

(Example) Examples of the present invention will be described below. FIG. 1 schematically shows an electrophotographic copying device among electrostatic recording devices. When the original 2 is set on the surface of the platen glass 1, the platen cover 3 is closed, and the copy start key is operated, the exposure light source 4 scans the original 2 for exposure in the direction of arrow a, and the light of the original 2 is exposed. The image is guided via a mirror 5.6 onto the surface of a photosensitive drum 7, which serves as an image-forming photosensitive member. The photosensitive drum 7 is a grounded metal cylinder with a photoconductive layer made of selenium or the like provided on the outer peripheral surface thereof, and rotates in the direction indicated by the arrow in conjunction with the exposure scanning.

Before the arrival of the optical image on the photosensitive drum 7, the photoconductive layer is, for example, uniformly charged by a charging electrode 8 to which a DC high voltage is applied, and the photoconductive layer in this state receives the optical image. Then, the conductivity of the area that receives the light increases, and the electrical charge in that area escapes to the metal cylinder, and positive charges remain in the dark area depending on the degree of brightness, and this causes the photoconductive layer to An electrostatic latent image corresponding to the image of the original is formed on the surface of the document.

When the portion on which this electrostatic latent image is formed reaches the developing sleeve 9a of the developing device 9, the negatively charged developer is attracted to the remaining positively charged portion of the photosensitive drum 7 by electrostatic force. Ru. As a result, a developer image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 7.

The transfer paper 10+ or 102 in the selected paper feed cassette 11+ or 112 is fed out by the conveyor belt 12 at a timing such that the leading edge of the transfer paper and the leading edge of the developer image coincide with each other. The developer image on the surface of the photosensitive drum 7 is transferred to the transferred transfer paper by the transfer pole 13 to which a DC high voltage is applied.

After that, the separation electrode 14 and separation claw 1 to which AC high voltage was applied
The transfer paper is separated from the photosensitive drum 7 by a conveyor belt 16, and the developer image is fixed thereon by a conveyor belt 16, and the receiver is discharged onto a tray 18.

Reference numeral 19 indicates a paper jam sensor that detects transfer paper that has arrived unseparated from the surface of the photosensitive drum 6 and remains wrapped around it; 20 indicates an eliminator that removes electrical charges from the photosensitive drum 6; and 21 indicates a paper jam sensor that removes the electrical charge remaining on the surface of the photosensitive drum 7. This is a cleaning device that removes developer.

In this embodiment, in such a copying apparatus, a protrusion 3a for detecting opening/closing is provided near the rotating base of the platen cover 3.
The main body 22 has a hole 22a through which the protrusion 3a is inserted, and a microswitch 23 is installed below the hole 22a.

Therefore, when the platen cover 3 is closed, the protrusion 3a passes through the hole 22a and activates the microswitch 23.
Closing of the platen cover 3 is detected.

In addition, there is a yellow printed area 3 in the form of a band on the inside of the platen cover 3.
b is provided. The yellow printing portion 3b is arranged on the platen glass 1 so as to be located on the upper surface of one side of the document reference edge 1a when the platen cover 3 is closed (FIG. 2). 24 is the yellow printing part 3b
It is a color sensor that detects the reflected light in the yellow light, and includes detection sections 24a to 24d that are sensitive only to yellow light.

The detection unit 24a is located at a position corresponding to the edge of a B5 original, the detection unit 24b is located at a position corresponding to an edge of an A4 original, and the detection unit 24C is located at a position corresponding to an edge of a B4 original. 24d are provided at positions corresponding to the edges of an A3 document. The color sensor 24 is installed obliquely below the above-mentioned one side of the document reference end 1a of the platen glass l.

The yellow printing section 3b and the color sensor 24 constitute a document size detection section, and when the platen cover 3 is closed and preliminary scanning is performed with the exposure light source 1, the light from the light source 1 passes through the platen cover 1. After being reflected by the yellow printed portion 3b of the platen cover 3, it becomes yellow light and is transmitted to the color sensor 2.
4.

Therefore, if, for example, a B5 original is placed on the platen glass 1 at this time, the reflected light will be incident on the detection sections 24b to 24d of the color sensor 24, but the reflected light will be incident on the detection section 24a. do not.

Therefore, when the detection units 24b to 24d detect yellow light, it is possible to detect that a B5 original is set. When an A4 original is set, the detection units 24a and 24b do not detect reflected light, and the remaining detection units 24c and 24d detect reflected light. Further, when a B4 original is set, the detection units 24a to 24c do not detect the reflected light, and only the detection unit 24d detects the reflected light. Furthermore,
If an A3 original is set, all detection units 2
No reflected light is detected for any of 48 to 24d.

As described above, by processing the detection output of the color sensor 24, the size of the document set on the platen glass 1 can be detected.

This detection signal is sent to the document size display section and is also used as a cassette selection signal to select one of the multiple loaded paper feeding power centers. The selected transfer paper is fed from the selected cassette.

Further, by appropriately processing the signal from the color sensor 24, it is possible to detect whether or not a document is placed on the platen glass 1. That is, if all of the detection units 24a to 24d of the color sensor 24 detect reflected light, the document is set in the chair, and if any one or more detects the reflected light, the document is placed. can be known.

FIG. 4 shows a block diagram for obtaining control signals, and a control circuit (CPU) 25 is connected to a signal input section using a matrix. This matrix contains
Contacts for the numeric keypad (0 to 9) for setting the number of copies, contacts for the copy start key CK, contacts for the stop clear key SC, contacts for the reduction/enlargement key MR, contacts for the copy density select key DK, and contacts for the cassette select key C8. , a DS key contact for setting the document size detection mode is provided. All keys for turning on these contacts are provided on the operation panel. A contact point for the microsinch 23 that detects the opening and closing of the platen cover is also provided within the matrix.

FIG. 5 is a flowchart for starting copying. After starting, first in step A, it is determined by the microswitch 23 whether or not the platen cover 3 is closed.

If it is closed, the process moves to step B, and it is determined whether or not the document size detection mode is set. If the mode is the document size detection mode, a document size detection operation is performed in step C, and the process moves to step D. On the other hand, if it is determined in step B that the mode is not the document size detection mode, it is determined in step F whether the DS key is on, and if it is on, document size detection is performed in step C. If it is not on, the process moves to step G and moves to step D without performing document size detection.

The above routine works before the copy start key is turned on.
When the platen cover is closed and the DS key is not turned on, if the DS key is turned on during that time, a document size detection operation will be performed, and if the copy key is turned on afterwards, copying will start and the detected size will be detected. A cassette loaded with originals of the same size is selected, and transfer paper is fed from there.

In the above description, the detection units 248 to 24d of the color sensor 24, which are sensitive only to yellow light, have two sensors with different wavelength sensitivities, and determine yellow light based on the ratio of their respective reflected light outputs. may be configured. Also,
When detecting the size of a document, when the platen cover is closed or the DS key is turned on, the optical system may be stopped at a position where the document can be irradiated, and scanning may not be performed.

(Effects of the Invention) As described above, according to the present invention, even if the platen cover is closed in a state where the document size detection mode is not set and the document size detection mode is selected thereafter, the exposure light source performs preliminary scanning and detects the document size. An action to detect is performed.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of the electronic copying device, Figure 2 is a diagram showing the relationship between the platen glass, yellow printing section, and color sensor, Figure 3 is an enlarged explanatory diagram of the vicinity of the platen cover, and Figure 4 is the control FIG. 5, which is an explanatory diagram of the large sword signal to the circuit, is a flowchart for starting copying. ■...Platen glass, 2...Document, 3...Platen cover, 3a...Protrusion, 3b...Yellow printing section,
4... Light source for exposure, 5.6... Vera-17... Photosensitive drum, 8... Charging electrode, 9... Developing device, 10...
・Transfer paper, 11... Paper feeding power cent, 12... Conveyance belt, I3... Transfer pole, 14... Separation pole, 15...
- Separation claw, 16... Conveyor belt, 17... Fixing device, 18... Receiver is plate, 19... Paper jam sensor, 20...
... Electrode removal, 21 ... Cleaning device, 22 ...
Main body, 22a... hole, 23... micro switch,
24... Color sensor, 24a-24d... Detection section, 25... Control circuit.

Claims (1)

[Claims] (1) In an electrostatic recording device configured to detect the document size with the platen cover closed, the electrostatic recording device is provided with a switching means for selecting the document size detection mode, and after the platen cover is closed, the document size is detected by the switching means. An electrostatic recording device characterized in that original size detection is performed by selecting a size detection mode.