JPS63249869A - Image forming device - Google Patents

Abstract

PURPOSE:To erase an image of a shadow caused by a floating part of a book original, by sending an operating signal to a center erasing member at a position of a latent image forming member corresponding to the book original center part calculated by detecting the light quantity by a center part detecting sensor at the time of a preliminary scan by an exposing device. CONSTITUTION:At the time of a center erasing mode, an exposing device 2 executes a pre-scan and executes a calculation of center detecting data. That is, when a light source 2a comes to a position of a central detecting sensor 6, a reflected light of a book original 5 is detected, and when a CPU reads a photodetecting signal for showing a fact that the reflected light is weaker than a reference, it is decided that the original is floating in a position corresponding to its photodetector and it is written in a RAM. By this data, center erasing timing data by an erasing device 11 placed so as to be opposed to a latent image forming member 3 is formed and stored, and when a copying process is executed by the next copy sequence, the latent image forming member 3 erases a latent image within a range corresponding to the erasing device 11. In such a way, a shadow of a floating part in the center of the book original can be erased completely.

Description

DETAILED DESCRIPTION OF THE INVENTION Drum 1υL1 The present invention relates to an image forming apparatus for copying a bound document such as a book in a facing state.

Spicy and distorted books or manuscripts bound like books (hereinafter referred to as book manuscripts)
2. Description of the Related Art Image forming apparatuses such as copying machines that make double-page copies are known. ′ When copying a book original in a two-page spread state, an image is formed on copy paper of the same size as the size of the book original in a two-page spread state. Generally, when a book manuscript is spread open, the center part of the book is lifted off the 112th surface of the manuscript, for example, from the contact glass.
The floating part will be copied black.

In order to prevent this raised area from being copied, the image at the center of the book original is erased by erasing the electrostatic latent image corresponding to the center of the copy paper.

Generally, when forming an image of a book manuscript, the manuscript is often aligned and copied using one edge as a reference. In this case, the center of the manuscript is lifted, so the actual length of the manuscript is longer than the theoretical length. On the other hand, copy paper is selected based on its theoretical length. During image formation, the central portion of the book document is lifted and moves as the actual length of the document is shortened. If you erase the part corresponding to the center of the copy paper in this state, this center part was set based on the copy paper that has not been shortened, and the position is different from the center of the original that has been apparently shortened due to lifting. For this reason, even if you erase the center part, part of the raised part of the original will remain copied in black.
The erase effect is not effective.

(2) It is an object of the present invention to provide an image forming apparatus which solves the above-mentioned conventional problems and makes it possible to always obtain copies in which shadow images caused by raised portions of book originals are erased.

In order to achieve the above-mentioned object, the present invention includes a center detection sensor arranged at a position corresponding to the center of a book document and whose position can be adjusted by a predetermined amount; It has a center erase member for erasing a part and a control device for the center erase member, and the control device is configured to operate an automatic center erase key and an automatic center erase key during preliminary scanning by an exposure device when the automatic center erase key is activated. The method further comprises means for calculating the center of a book document by detecting the amount of light by the center detection sensor, and sending an activation signal to the center erase member at a position of the latent image forming member corresponding to the center of the book document. do.

The structure and operation of the present invention will be explained in detail based on the embodiment shown in the drawings.

FIG. 1 shows an image forming apparatus, which is a known copying machine, to which the present invention is applied.

A document is placed on a document table 1 of a copying machine, and the document is illuminated by a scanning exposure device 2 including a light source 2a, a reflecting mirror 2b, etc.
An electrostatic latent image is formed on a latent image forming member 3, such as a photosensitive drum, by a known method using reflected light from the original. An image based on the latent image is formed on copy paper by the transfer member 4.

A known example of a control system for this copying machine is shown in FIG. A detailed explanation will be omitted.

As shown in FIGS. 3 to 5, a center detection sensor 6 is provided on the back of the document placement table l at a position corresponding to the center of the book document spread when the book document 5 is placed. It will be done. The center detection sensor 6 is arranged to receive light reflected from the original 5 when the exposure device 2 performs preliminary scanning exposure.

The center detection sensor 6 is formed to be movable within a predetermined length range so that it can be moved to the center even if the size of the document changes.

The center detection sensor 6 has a plurality of sensor groups, for example, nine light receiving elements 7 in the figure, as shown in FIG. As the light receiving element 7, an element similar to an original density reading sensor (ADS) can be used.

Each light receiving element 7 is connected to an analog switch 8 as shown in FIG.
The analog switch 8 is connected to the CPU 9.

Adjustment is made so that the center of the sensor group of the center detection sensor 6 (fifth element in the figure) is at the center of the copy paper size (B5 size in the illustrated example). A scale indicating the copy paper size, for example A5, B5, A, is provided on the machine frame to which the center detection sensor 6 is attached.
4 scale (see FIG. 6) is attached, and the center of the sensor group of the center detection sensor is aligned with this scale.

The operation unit 10 of the control device uses a key arrangement as shown in FIG. 8, which includes a book document automatic center erase key and other necessary keys, but is not particularly limited thereto.

When the print switch (or start switch) is pressed on the operation unit 10, the control device controls the image forming apparatus according to the flow shown in FIG. 9 and other normal copying operation procedures. In Figure 9, key reception and processing are performed in WT mode, and center erase is turned off.
Controls whether the switch has changed from ON to ON. In other words, the operation part 1
0, it is asked whether the book automatic center erase key has been pressed. If NO, it is a normal copy, so the process proceeds to the step of determining whether the print key is ON or not, and Y
At the time of ES, that is, when the center erase key is pressed, the center detection unit, that is, the center detection sensor is moved to the center position according to the copy paper, and it is determined whether or not the post print key is ON. If the print key is not pressed and the answer is NO, the process returns to the beginning; if the print key is pressed and the answer is YES, it is determined whether or not the center erase mode is in effect. When the center erase mode is NO and there is no need to perform a center erase, a normal copy sequence is performed. When the center erase mode is YES, the exposure device 2 (an exposure device for pre-scanning can be installed separately) performs a pre-scan and uses the center detection data. Perform the calculation.

That is, when the light source 2a comes to the position of the central detection sensor 6,
For example, the 0 reflected light that detects the reflected light of the book manuscript is ■～■
Detected by nine light receiving elements of
When read, it is determined that the document is floating at the position corresponding to the light receiving element and is written into the RAM. This data determines the area where the document is floating, so the eraser placed opposite the latent image forming member 3 Form and store center erase timing data by the device.

As a result, when the copying process is performed in the next copy sequence, the latent image forming member erases the latent image in the range corresponding to the floating portion of the document by the erase device 11.

The copy sequence is continued in a known manner until the set number of copies have been made, and when the set number of copies is completed, the process returns to the beginning.

As a result of performing the copying process in this way, conventionally the result is shown in Figure 1O (
As shown in A), the center erase part B is misaligned with respect to the floating part A, and a black shadow image remains in the shaded part C. However, according to the present invention, the center erase part B is misaligned with respect to the floating part A, as shown in FIG. Gana (The shadow part is definitely erased.

The present invention has made it possible to completely eliminate the shadow of the floating part in the center of a book manuscript. Moreover, there is no need to manually set the floating area, and the erase width is automatically set, making the work easier and more reliable.

When erasing the image in the central floating area, a book document center detection sensor is provided, and since the erase location can be detected from the document, control is more reliable than when copy paper is used as a reference.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram of a copying machine as an image forming apparatus using the present invention, Fig. 2 is a block diagram of a control system of the copying machine shown in Fig. 1, and Fig. 3 is an explanatory diagram of a copying machine as an image forming apparatus using the present invention. 4 is a plan view of FIG. 3, FIG. 5 is a side view of FIG. 3,
FIG. 6 is a schematic diagram of the book document center detection sensor, FIG. 7 is a circuit diagram of the center detection sensor, FIG. 8 is a schematic diagram of the operation section of the control device, and FIG. 9 is a part of the control operation of the control device according to the present invention. FIG. 10 is a diagram showing the relationship between the raised center portion of the book original and the erased portion of the copy paper, where A is a conventional example and B is an example according to the present invention. L...Document mounting table 2...Exposure device 3...Latent image forming member 4...Transfer member 5...Document
6...Central detection sensor 7...Light receiving element (1 other person) Fig. 6 A4B5A5

Claims (1)

[Claims] An exposure device that scans and exposes a document placed on a document table, a latent image forming member that forms an electrostatic latent image, and a transfer member that transfers the image formed on the latent image forming member to copy paper. The image forming apparatus includes a center detection sensor arranged at a position corresponding to the center of a book document and whose position can be adjusted by a predetermined amount, and a center for erasing a part of the latent image of the latent image forming member. an erase member, and a control device for the center erase member, the control device including an automatic center erase key and, when the automatic center erase key is actuated, the center detection sensor during preliminary scanning by the exposure device. An image forming apparatus comprising means for calculating the center of a book document by detecting the amount of light and sending an activation signal to the center erase member at a position of the latent image forming member corresponding to the center of the book document.