JPH03134680A - Picture forming device - Google Patents

Abstract

PURPOSE:To speedily detect the size of an original by executing original end part detecting and picture forming operations, etc., by an original size detector integrated with an optics in the outgoing path and incoming path of the optics to be relatively moved between first and second prescribed home positions to an original platen. CONSTITUTION:An optics 2 to be relatively moved to an original platen 1 is reciprocatively moved between a first home position 6 as an exposure ending position and a second home position 7 as an exposure starting position. At the outgoing time of the optics 2, the end part and concentration of an original 4 are detected by original size detectors 3a-3d and an original density detector 5 respectively. At the incoming time, the picture forming operation is executed and the optics 2 is returned to the position 6. Then, the original size or the original density are speedily detected in a short time and picture formation is efficiently executed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer. The present invention relates to an image forming apparatus that detects the size of a document placed at a predetermined position on a document table using a document size detector provided on the optical system side.

℃Prior Art] In a conventional copying machine of this type, an optical system is provided so as to be movable relative to, for example, a document table, and the optical system includes a document placed at a predetermined position on the document table. An optical document size detector is installed to detect the size of the document. Prior to the copying operation, the optical system is configured to move back and forth (prescan) to detect the size of the document.

In other words, after opening the document holding cover, when the document is placed at a position (predetermined position) with its edge aligned with the document table on the side of the exposure start position of the optical system during copying operation, the exposure of the optical system will start. The optical system moves from the home position set on the start position side toward the other end of the document (exposure end position side), and enters a standby state at this exposure end position side. When the copy button is operated, the optical system returns to the home position and then starts moving toward the other end of the document again. Then, after a change position where the surface of the document is interrupted is detected by the document size detector that moves together with the optical system, the optical system returns toward the home position on the exposure start position side.

As described above, the length of the document on the document table is measured, and the size of the document is detected based on this value.

Thereafter, the optical system is reciprocated between the home position and an exposure end position corresponding to the other end of the document, and a copying operation is performed.

In addition, in the conventional device described above, the optical system is moved back and forth twice to detect the size of the document, but in the device III, the optical system is moved back and forth once to detect the size of the document. Things are also being developed.

[Problem to be solved by the invention]

In the conventional copying machine configured as described above, in order to detect the size of the original, the optical system must be moved back and forth once or twice between the home position and the exposure end position, and the first It takes a considerable amount of time to complete the copying operation on the second copy sheet.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus that can detect the size of a document in a short time and perform image forming operations extremely efficiently.

[Means to solve the problem]

In order to achieve the above object, the main means adopted by the present invention is to move an optical system relative to the document table and use a document size detector disposed on the optical system side. In an image forming apparatus that detects the size of a document placed at a predetermined position on a document table, the exposure end position side and the exposure start position of the optical system relative to the document table during image forming operation in the image forming device The position sides are respectively set as first and second home positions of the optical system or document table, and the optical system or document table is moved on a forward path from the first home position to the second home position. the end of the document is detected by the document size detector to calculate the size of the document, and the optical system or the document table is moved on a return path from the second home position to the first home position. Ii according to the point that the image forming operation is carried out by the user and the image is returned to the first home position.
There is an image forming device.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples embodying the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. It should be noted that the following examples are examples embodying the present invention, and are not intended to limit the technical scope of the present invention.

Here, FIG. 1 tal is a side view showing the structure of the main part of an image forming apparatus according to an embodiment of the present invention, and FIG.
FIG. 2 is a block diagram of the control system of the image forming apparatus, and FIG. 3 is a flowchart showing the operating procedure of the image forming apparatus.

In the image forming apparatus according to this embodiment, as shown in FIG. 1 and FIG.
The optical system 2 includes a plurality of optical reflective document size detectors 38 to 3.
f is attached.

The document size detector 3g is for detecting the length of the document 4 placed at a predetermined position on the document table 1 by detecting the edge of the document 4. If the original 4 is of a predetermined standard, the size of the original 4 can be detected only by the original size detector 3f.

The above document size detector 3. 3e to 3e are arranged on a plane parallel to the plane of the original loading table 1 and in a direction perpendicular to the moving direction of the optical system 2. Then, the document size detector 3. . . . 38, the width dimension of the non-standard document is detected.

On the optical path of the reflected light after being exposed by the optical system 2, there is an original density detector 5 (A
E detector) is installed.

Here, what should be noted in the image forming apparatus is that the relative exposure end position side and exposure start position side of the optical system 2 with respect to the document table 1 during the image forming operation are 1 home position 6 and a second home position 7.

Then, the optical system 2 is moved to the first home position 6.
The end of the original 4 is detected by the original size detector 3f to calculate the size of the original 4, and the density of the original 4 is then calculated. A detector 5 detects the density of the original 4, and the optical system 2 is moved on a return path 9 from the second home position 7 to the first home position 6 to perform an image forming operation. has been done.

Control for operating as described above is realized by an operating program stored in advance in the memory within the microcomputer 10.

Next, the operation procedure of the image forming apparatus will be explained based on FIG. 3.

In addition, 31. S2. ...indicates each operation step.

First, the closing operation of the document holding cover is detected by the cover detector 11.
(See Figure 2) When the original detector 12 determines that the original 4 is placed at a predetermined position on the original platen 1 (S2), the optical system 2 It starts moving from the home position 6 toward the second home position 7 (S3).

When the edge of the original 4 is detected by the original size detector 31 on the outward path 8 of the optical system 2, the size of the original 4 is calculated by the microcomputer 10 (S4).

That is, by subtracting the distance between the first home position 6 and the end of the document 4 from the known movable distance (total stroke) of the optical system 2, the length of the document 4 is calculated. , based on this value, the size of the original document 4 that is of a predetermined standard is detected.
detected by e.

When the cover is closed, the lamp 2 of the optical system 2 is placed at a position corresponding to the edge of the document 4. is turned on (S5), and the optical system 2 further moves on the outward path 8 toward the second home position 7 (36).

When the lamp 2a is turned on, the density of the original 4 is read by the original density detector 5 from the reflected light after being exposed by the lamp 2° (S7). The process ends when the optical system 2 is moved to a position corresponding to the other end (S8).

Then, when the optical system 2 reaches the second home position 7, the optical system 2 is stopped (S9).

After that, wait for the copy button to be operated (S10)
, the optical system 2 is moved from the second home position 7 toward the first home position 6, and a copying operation is performed while moving on this return path 9 (Sll).

As described above, in the image forming apparatus according to the present embodiment, the optical system 2 is simply moved one way on the outgoing path 8 from the first home position 6 to the second home position 7, and the size of the original 4 is changed. Concentration can be detected.

Therefore, compared to the conventional apparatus, the time required to detect the size and density of the document is dramatically reduced, and the entire image forming operation can be carried out extremely efficiently.

In this case, it goes without saying that even in an apparatus configured to be able to detect only the size of the original document, the entire image forming operation can be carried out in an extremely efficient manner.

Furthermore, in the apparatus of this embodiment, since the optical system 2 is configured to perform a copying operation when moving on the return path 9 from the second home position 7 to the first home position 6, The size detection, density detection and copying operation of the original 4 can all be completed by reciprocating the optical system 2 once.

In the above embodiment, the optical system 2 is moved relative to the document table 1. However, it is possible to move the document table 1 relative to the optical system 2. Needless to say, the present invention can also be applied to an image forming apparatus configured as follows.

〔Effect of the invention〕

As described above, the present invention moves an optical system relative to the document table and detects the size of the document placed at a predetermined position on the document table using a document size detector installed on the optical system side. In the image forming apparatus to be detected, the relative exposure end position side and exposure start position side of the optical system with respect to the document table during the Ii image forming operation in the image forming apparatus are the first and second positions of the optical system or the document table, respectively. The end of the document is detected by the document size detector by moving the optical system or the document table from the first home position to the second home position on a forward path. calculate the size of the document, and perform an image forming operation by moving the optical system or the document table on a return path from the second home position to the first home position, and return to the first home position. Since the image forming apparatus is characterized in that it can be reset, the size of the document can be detected in a short time, and the image forming operation can be performed extremely efficiently.

[Brief explanation of the drawing]

FIG. 1 (5) is a side view showing the structure of the main parts of an image forming apparatus according to an embodiment of the present invention, FIG. is a block diagram of the control system of the image forming apparatus, and FIG. 3 is a flowchart showing the operating procedure of the image forming apparatus.・・Document size detector 4・・Document 5・・Document density detector (AE detector) 6・・First home position 7・・Second home position 8・・Outbound path 9・・・Return trip 10...Microcomputer Sl to 311...Operation step

Claims (1)

[Claims] 1. The optical system is moved relative to the document table, and the size of the document placed at a predetermined position on the document table is detected by a document size detector installed on the optical system side. In the image forming apparatus to be detected, the relative exposure end position side and exposure start position side of the optical system with respect to the document table during the image forming operation in the image forming apparatus are respectively referred to as the first and the first positions of the optical system or the document table. the second home position, and the optical system or document table is moved on a forward path from the first home position to the second home position, and the edge of the document is detected by the document size detector. calculates the size of the document, moves the optical system or the document table on a return path from the second home position to the first home position, performs an image forming operation, and returns to the first home position. An image forming apparatus characterized in that: