JPH08127442A - Image forming device - Google Patents

Abstract

PURPOSE: To perform detection of a blank paper sheet without effecting prescanning by a method wherein when a document is detected to be blank, a paper sheet is waited at a storage part once and after the document is reset, the paper sheet is conveyed to an image forming part. CONSTITUTION: A document image under movement is read by an image sensor 10, a pixel is counted by a laser beam scanner 11 from image data and when the value is below a given value, detection of a document blank is effected. When the document blank is detected, image forming treatment is not applied on a paper sheet already fed, which is conveyed to a turn-over part (DM) 21 used during recording on both sides, and the feed of a subsequent paper is stopped. In this case, it is displayed by a user interface U1 that the back of the document is installed and an operator is urged to effect resetting. Along with the starting of operation after resetting of the document, the paper sheet at the DN part 21 is conveyed to an image forming part containing a photo-sensitive drum 12. This constitution performs utilization of a paper sheet already conveyed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention conveys a document at a constant speed, and the moving document is exposed by a CVT (moving document reading) system in which a document image is read by a fixed exposure scanning unit and the document is set on a platen glass and exposed. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus equipped with a platen scan (still original reading) system in which a scanning unit is moved to read an original image, and more particularly, to an image forming apparatus capable of detecting an original white color simultaneously with an original scanning operation without performing prescan. .

[0002]

2. Description of the Related Art Conventionally, a technique for preventing a white copy by placing a document by mistake in an automatic document feeder (hereinafter referred to as ADF) is disclosed in, for example, Japanese Patent Application No. 5-562.
No. 20 is proposed. FIG. 4 shows the flow of the conventional method. The original is pre-scanned, the black data of the read image is counted by the adder, and the presence or absence of image data for one sheet is determined. If there is image data, the copy operation continues.
If there is no image data, the user interface U
I indicates that the original is placed on the back side and the copying is stopped. However, in the conventional white copy prevention method, since the copy control is performed after first detecting the presence or absence of the image data of the first sheet by the prescan, the time until the first sheet is output during the copy operation and Number of copies per minute (FCOT & CP
There is a problem that it affects M). An object of the present invention is to provide an image forming apparatus capable of detecting a document white color at the same time as a document scanning operation without performing a prescan.

[0003]

In order to achieve the above object, the invention of claim 1 conveys an original at a constant speed, and the image information of the moving original is exposed and scanned by a fixed reading unit,
In an image forming apparatus for recording an image on a sheet in an image forming section, a storage section for temporarily storing the sheet on which an image has been formed, an original white detection unit for detecting an original white color simultaneously with exposure scanning of a moving original, and an original white detection When the white color of the original is detected by the means, the image forming control means for stopping the image recording operation, the paper conveyance control means for controlling the conveyance of the sheet from the storage section to the image forming section, and the white color of the original is detected by the white color detection section of the original. Display means for displaying that the sheet has been detected, and the paper feed control means records the paper fed to the image forming section immediately before the image forming control means stops the image recording operation from the image forming control means. According to the stop command, the sheet is conveyed to the storage section, and the sheet is conveyed to the recording image forming section as the sheet for the subsequent recording operation.

[0004]

According to the above construction, since prescanning is not performed in the image recording control by moving document reading which starts conveying the sheet at the same time as reading the document, when the document white detecting means detects the document white, the recording sheet is already supplied. The image forming process is not performed on the sheet fed from the unit, the sheet is conveyed to the storage unit, and the feeding of the next sheet from the recording sheet supply unit is stopped. At this time, it is displayed on the display means that the back side of the document is set, and the operator is prompted to set again. When the operation is started after the original is set again, the paper stored in the storage section in the subsequent recording operation is conveyed to the image forming section. In this way, the sheet that has already been conveyed at the time of detecting the white color of the original document can be used as the sheet for the subsequent recording operation without being discharged.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an image forming apparatus to which the present invention is applied. A platen cover 1 is provided on the upper part of the apparatus main body so as to be openable and closable, and an automatic document feeder (ADF) 2 integrated with the platen cover 1 is provided. The document reading device places a document on the platen glass 3,
A stationary document reading unit that moves the light source unit 4 to perform exposure scanning and a document 6 is loaded on a document tray 5 of the ADF 2.
Automatically feeds one sheet at a time, conveys the original 6 at a constant speed,
The moving document reading unit is configured to expose and scan the moving document with the light source unit 4 fixed at a predetermined position. The document read by the moving document reading unit is discharged to a document discharge tray 7 provided on the upper surface of the platen cover 1.

The exposure scanning device includes a light source unit 4, a mirror 8 for guiding the reflected light from the original document in a predetermined direction, a lens 9 for condensing the reflected light, and the condensed reflected light for incidence to be converted into an electric image signal. It is composed of a CCD image sensor 10. The laser beam scanner (ROS device) 11 is a CCD
An electrostatic latent image is formed on the surface of the photosensitive drum 12 based on the image signal converted by the image sensor 10. Then, the electrostatic latent image formed on the photosensitive drum 12 becomes a toner image visualized by the developing unit 13. Then, the toner image is transferred to the sheet fed from the recording sheet feeding unit 13 by the transfer unit 15, fixed by the fixing unit 16, and discharged to the face-down sheet discharging tray 17 or the face-up sheet discharging tray 18.

The sheet discharged to the face-down sheet discharge tray 17 is stopped in a state where it is nipped by a reversibly rotatable conveyance roll provided near the tray entrance. At the time of the second side recording of the double-sided recording (DM), the conveyance roll provided near the entrance of the face-down sheet discharge tray 17 is reversed to convey the sheet to the DM section 21. The outlet of the DM section 21 merges with the downstream side of the photosensitive drum 12. The paper is turned over by the DM unit 21, and the second surface is recorded by the photosensitive drum 12.

In the present embodiment, the DM unit for reversing the paper at the time of double-sided recording is used as a storage unit for temporarily storing the paper already conveyed from the paper feeding unit to the image forming unit (photosensitive drum) at the time of detecting the blank paper after the image formation. 21 is used to feed the paper stored in the DM section 21 to the image forming section during the subsequent image formation. The residual toner on the photosensitive drum is removed by the cleaning unit 19 and then charged by the charging unit 20 to write the next image. Reference numeral 22 is a manual feed tray.

Next, the operation of the above configuration will be described. A sheet material as a recording medium accommodated in the recording sheet supply unit 13 is fed to each conveying path by a sheet feeding roller and is positioned in front of the photosensitive drum 12 and is a registration roller for positioning and timing the sheet material. It is sent to and stopped. The registration roller conveys the sheet material to the photosensitive drum 12 at the timing of the image forming process. The paper after image formation is fixed, and the paper discharge tray 17 is used according to the recording mode.
Or discharged to 18. Paper is discharged to the face-up paper discharge tray 18 after the first-side recording during normal single-sided recording and after the second-side recording during double-sided recording. Further, the sheet material after the first side recording during double-sided recording is accommodated in the face-down sheet discharge tray 17. Further, the sheet material after the first-side recording during the normal recording or after the second-side recording during the double-sided recording is accommodated in the face-up paper discharge tray 18.

A conveying path to the face-down sheet discharging tray 17 for discharging the fixed sheet and a conveying path to the face-up sheet discharging tray 18, or from the face-down sheet discharging tray 17 at the time of recording on the second side to the DM section 21. Deflection means (not shown) for switching the conveyance path of No. 1 and deflection means (not shown) for switching the conveyance path to the DM section and the face-up sheet discharge tray are provided.

FIG. 2 shows a hardware configuration for realizing the functions of the present invention. The main body control means has a function of controlling the entire image forming apparatus. As a basic configuration, the main body control means processes the image data of the original read by the moving original reading means, and determines whether the original surface is white or whether there is image information from the image data. Image formation for performing control of recording on the sheet fed from the recording sheet supply unit by the document white detection unit for detecting and the sheet conveyance control unit, and control for stopping recording when the document white is detected Equipped with control means.
Further, in the image recording by the moving document reading, the paper conveyance control means has already fed (FEE) from the recording paper supply section based on the recording stop signal issued from the image formation control means.
The sheet D) is once housed in the DM section used as a storage section, and is controlled to be conveyed to the image forming section in response to the next sheet feeding command. Here, the image forming unit includes a photosensitive drum, a transfer unit, a fixing unit, and the like.
The input means constitutes a user interface (UI), and inputs image recording conditions (for example, mode settings such as normal recording mode and double-sided recording mode, paper size, number of sheets, tray selection, paper ejection processing designation, etc.). The notification means displays on the UI that the document is placed on the back side based on the document white detection by the main body control means.

Next, the operation of this embodiment will be described. FIG. 3 is a control flow when applied to a copying machine. When the original is set on the ADF and the start button is pressed to start copying, the first original is fed (FEED) (S1),
Read one line (S2). Pixels (PIXEL) are counted while writing the image data of the read original by a laser writing device (ROS) (S
3), copy operation is performed (S4). The above operation is performed for one sheet.

The end of the copying operation for one sheet is judged (S
5) If Yes, it is determined whether the pixel value for one sheet is "0" (S6). When the pixel value is not "0", that is, when the white color of the original is not detected, the copying operation is continued (S7). When the pixel value for one sheet is “0”, the copy sheet is conveyed to the DM section for inverting (S
9) The UI indicates that the original is placed on the back side (S9), and the copying operation is stopped (S10). The operator looks at the UI display and resets the document (S1).
1). Thereafter, copying is started (S12), and when the document is read (S13), the paper is fed from the DM section (S14) and the copying operation is continued (S15). In the present embodiment, it is described that the sheet is conveyed to the DM section when the blank sheet is detected and is used as the first sheet in the next copying operation, but the present invention is not limited to this, and the sheet is accommodated in the DM section. The paper is available for any subsequent copying operation.

[0014]

As described above, according to the present invention, in the moving original reading method in which the reading of the original image and the detection of the white of the original are simultaneously performed during the movement, the sheet already fed when the white of the original is detected is temporarily stored. With the department waiting,
Since this sheet is conveyed to the image forming unit after the original is set again, it is possible to detect a blank original without damaging FCOT or CPM.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an image forming apparatus to which the present invention is applied.

FIG. 2 is a block diagram showing a hardware configuration for realizing the functions of the present invention.

FIG. 3 is a control flow diagram when applied to a copying machine.

FIG. 4 is a flowchart of a conventional copying machine.

[Explanation of reference numerals] 1 ... Platen cover, 2 ... Automatic document feeder, 3 ... Platen glass, 5 ... Document tray, 6 ... Document, 7 ... Document discharge tray, 10 ... CCD image sensor, 11 ... Laser beam scanner, 12 ... Photosensitive drum, 13 ... Developing section, 1
4 ... Recording paper supply unit, 15 ... Transfer unit, 16 ... Fixing unit, 1
7 ... Face-down paper discharge tray, 18 ... Face-up paper discharge tray

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G01N 21/47 B G03G 15/00 107 15/043 15/04 H04N 1/00 106 C 1/04

Claims (1)

[Claims] 1. An image forming apparatus in which an original is conveyed at a constant speed, image information of the moving original is exposed and scanned by a fixed reading unit, and an image is recorded on a sheet by the image forming unit. A storage unit for temporarily storing sheets, a document white detection unit for detecting the document white simultaneously with the exposure scanning of the moving document, and a document white detection unit for detecting the document white,
An image forming control means for stopping the image recording operation, a paper carrying control means for carrying the paper from the storage section to the image forming section, and a display means for displaying that the white color of the original has been detected by the white color detecting section. A sheet fed to the image forming section immediately before the image recording control section stops the image recording operation, and the sheet conveyance control section conveys the sheet to the storage section based on a recording stop command from the image forming control section. An image forming apparatus, wherein the sheet is conveyed to a recording image forming unit as a sheet for a later recording operation.