JPS6291930A - Copying device - Google Patents

Abstract

PURPOSE:To prevent the erroneous detection of an original size due to a shutter at the time of the absence of an original by providing an original detecting sensor, which detects the presence or the absence of the original on a platen glass, on a platen cover and opening wholly the shutter when the original is absent. CONSTITUTION:When a platen cover 7 is closed, the detection signal of an original detecting sensor 13 is checked. This sensor 13 is turned on at the time of the presence of the original but is turned off at the time of the absence of the original. If the original exists on a platen glass 1, shutters 4 and 4' are moved forward to operate original detecting sensors 6 and 6', and their front edges 3 and 3' are allowed to coincide with peripheral edge parts 2 and 2' of the original. Thereafter, a copy form and a reduction magnification are selected. If the original does not exist, shutters 4 and 4' are opened wholly. Thus, a device is set to the state where an automatic original carrying device 11 can send the original onto the platen glass 1; and the exposure operation or the like is inhibited by the detection signal of the absence of the original to prevent unnecessary copying.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a copying apparatus having a document size detection function.

``Prior Art'' Generally, in a copying apparatus, a copy can be made on a predetermined copy paper by placing an original on a platen glass and pressing a print start button. When two or more types of trays containing copy paper are installed, the tray containing copy paper of the same size as the original is usually selected from among them to make a copy. This selection change is performed by operating keys on the console panel.

In a copying apparatus that has the function of making enlarged/reduced copies, it is necessary to select copy paper of a size equal to the original size multiplied by its reduction ratio.

However, if you make a mistake in calculating this reduction ratio or forget that you need to select the appropriate size of copy paper,
Miscopy will occur.

To prevent this, conventionally, when the size of the original is automatically determined and the reduction ratio is kept constant, copy paper of the appropriate size is automatically selected each time the original is replaced. , if you want to keep the copy paper size constant,
Some copying machines operate to automatically select a reduction ratio depending on the size of the original.

On the other hand, in response to the original placed on the platen glass,
There is one in which a shutter provided on the lower surface of the platen glass is opened and closed so that the light from the light source is irradiated only on an area commensurate with the size of the document.

FIG. 3 is a schematic diagram of such a device.

In the figure, when a document 2 is set on the platen glass 1, two shutters 4.4' arranged such that their front edges 3.3' are perpendicular to each other move forward in the direction of the arrow 5.5'. This shutter 4.4' has an opaque sheet that blocks light directed upward from the platen glass from a light source (not shown) located below, and a front edge 3.3' of the shutter 4.4'.
and a drive section (not shown) that moves forward and backward in a direction perpendicular to the direction. and the front edge 3. of both shutters 4.4'.
3' are stopped so as to overlap the peripheral edges 2', 2' of the document 2, respectively, to prevent unnecessary light from leaking to the outside during exposure.

Such a copying device is known, for example, from Utility Model Application No. 58-65057.
JP-A-58-85459. Here, an original detection sensor 6.6' is attached to the front edge 3.3' of the shutter 4.4', and this detection signal causes the front edge 3.3' of the shutter 4.4' to When approaching the periphery of 2, its advancement is automatically stopped. Therefore, as shown in the figure, when the advance of both shutters 4.4' is stopped and exposure preparation is completed, the leading edge 3.3'
The document size can be detected by checking the position of the shutter, that is, the amount of advance of the shutter.

By utilizing this, it is also possible to perform the automatic selection of copy paper described above.

"Problems to be Solved by the Invention" With such a copying apparatus, after setting the original 2 on the platen glass 1, it is possible to make good copies even if the platen cover 7 is left open and exposed. Furthermore, there is no risk of the operator's eyes being damaged by the light from the light source.

On the other hand, when copying is attempted with the platen cover 7 closed, there is a problem in that the white surface of the platen cover 7 facing the platen glass 1 is mistakenly detected as the document surface.

Furthermore, in order to improve the efficiency of copying operations, some copying machines are equipped with an automatic document feeder that automatically feeds copy sheets onto the top surface of a platen glass.

This automatic document feeder feeds a document onto a platen glass and discharges the document when exposure is completed. Then, the next document is sent.

However, if the shutter erroneously detects the bottom surface of the automatic document feeder above the platen glass as the document surface and outputs a document size detection signal, the automatic document feeder may be prohibited from feeding the document. . and,
Blank copies may be made without the original being sent in.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a copying apparatus that prevents the shutter from erroneously detecting a document as described above.

"Means for Solving the Problems" The copying apparatus of the present invention has a shutter which is provided on the lower surface of the platen glass and blocks light directed upward from the platen glass from the light source, and this shutter has a leading edge thereof separated from the shutter. In addition to increasing and decreasing the shielding area by opening and closing the cover by moving it forward and backward in orthogonal directions, the document detection sensor attached to the front edge detects the position of the peripheral edge of the document on the platen glass, and the document size is determined from the position of the leading edge at that time. In those that make judgments,
A document detection sensor is provided on the platen cover, which is attached to the platen cover so as to be openable and closable so as to cover the top surface of the platen glass, and when the platen cover is closed, this document detection sensor detects the presence or absence of a document. The feature is that the shutter is fully opened.

"Function" In this way, the platen cover is provided with a document detection sensor that detects the presence or absence of a document on the platen glass.
If you open the shutter fully when there is no document, you can prevent the shutter from incorrectly detecting the size of the document when there is no document.

As a result, even when an automatic document feeder is attached, documents can be sent out smoothly.

On the other hand, if there is a document on the platen glass,
The shutter operates normally and the document size can be detected.

Embodiment FIG. 1 is a block diagram showing an embodiment of a copying apparatus of the present invention.

In the figure, an original 2 is set on the platen glass 1, and two shutters 4.4' extend the front edges 3.3' of the original 2 to the peripheral edges 2', 2' of the original 2, respectively. The platen cover 7 has an automatic document feeder 11 on its top surface.
is installed. Therefore, in this embodiment, the lower surface of the platen cover 7 has a conveyor belt I2 for conveying the original.
is exposed.

A document detection sensor 13 is attached to detect the document 2 on the platen glass 1 through a gap (not shown) in the conveyor belt 12.

The detection signal 13S of the document detection sensor 13 is the detection signal 6S of the document detection sensor 6.6' attached to the front edge 3.3' of each shutter 4.4'.

It is input to the control circuit 16 together with 6'S.

The control circuit 16 includes an interface 17 and a CPU 18.
(microprocessor) and ROM (read-only)
It is composed of a RAM (Random Access Memory) element 19, a RAM (Random Access Memory) element 20, and a pass line 21 connecting these elements.

The interface 17 is a circuit for receiving detection signals from each sensor, and the CPU 18 not only detects the document size but also controls the operations of other parts of the apparatus. R
The OM element 19 stores various control programs including a document size detection operation, and the RAM element 20 is an element that temporarily stores data necessary for executing the programs.

The above-mentioned apparatus operates according to the flowchart shown in FIG. 2, for example.

This operation is suitable when the platen cover 7 is closed and the copying operation is performed manually, or when the platen cover 7 is closed and the automatic document feeder 11 is used to feed a document and the copying operation is performed.

First, the condition of the platen cover 7 is checked (step ■). When the platen cover 7 is open, operations such as setting an original on the platen glass 1 and making copies using the shutter function are possible.

When the platen cover 7 is closed, the document detection sensor 13
Check the detection signal (step ■). Here, it is assumed that the document detection sensor 13 is turned on when there is a document, and is turned off when there is no document. When there is an original on the platen glass 1, the shutter 4.4' is advanced to activate the original detection sensor 6.6', and the front edge 3.3' is moved to the peripheral edge of the original as shown in the figure. 2. Match 2'. Thereafter, the process moves on to selecting the copy paper and the reduction ratio (step ■).

On the other hand, if there is no document, the shutter 4.4' is fully opened (step ■).

This puts the automatic document feeder 11 in a state where it can immediately feed the document onto the platen glass 1, and also prevents operations such as exposure due to the no-document detection signal, thereby preventing unnecessary copies from being made. .

"Variation" The copying apparatus of the present invention is not limited to the above embodiments.

The document detection sensor provided on the platen cover may be located anywhere as long as it can detect the presence or absence of a document. Furthermore, sufficient effects can be obtained by using the apparatus of the present invention even in those without an automatic document feeder.

``Effects of the Invention'' The copying apparatus of the present invention as described above can erroneously detect the original size and make unnecessary copies when the original is not set on the platen glass. It does not interfere with its smooth operation when used.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a copying apparatus according to the present invention;
FIG. 2 is a flowchart of the operating program, and FIG. 3 is a schematic diagram of the main parts of a copying apparatus suitable for carrying out the present invention. 1...Platen glass, 3.3'...Front edge of shutter, 4.4'...
...Shack, 6.6'...Shutter document detection sensor, 7.
...Platen cover, 11...Automatic document feeder, 13...Document detection sensor for platen cover. Applicant: Fuji Xerox Co., Ltd. Agent

Claims (1)

[Claims] 1. A shutter is provided on the lower surface of the platen glass to block light directed upward from the platen glass from a light source, and the shutter is opened and closed by moving its front edge forward and backward in a direction perpendicular to the shutter. The platen increases or decreases the shielding area, detects the position of the peripheral edge of the document on the platen glass by a document detection sensor attached to the leading edge, and determines the document size from the position of the leading edge at that time. A document detection sensor is provided on the platen cover, which is attached to the platen cover so that it can be opened and closed to cover the top surface of the glass. When the platen cover is closed, this document detection sensor detects the presence or absence of a document, and when it is determined that there is no document, the shutter is activated. A copying device characterized in that it is fully opened. 2. The copying apparatus according to claim 1, wherein the platen glass is provided with an automatic document feeder.