JP4117885B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a digital copying machine, a printer device, a facsimile machine, or a digital multifunction machine having these functions, and more particularly to a technique for erasing unnecessary image data generated when a document is read.

When the document is read, the image data at the edge of the document tends to be unstable, and unnecessary image data is added. The cause of unnecessary image data varies depending on the document reading method.
When a document is read using a sheet-through type automatic document feeder, the document itself is read while moving, so that a shadow at the edge of the document may occur in the image data.
Further, when an original is placed on the contact glass and the original is read with the pressure plate placed on the original, a shadow such as a member for placing the original horizontally may occur in the image data at the end of the original. In order to solve such problems, conventionally, techniques described in the following patent documents have been proposed.
JP 2001-298605 A JP 07-336522 A Japanese Patent Laid-Open No. 10-243168

However, according to the conventional technology, when erasing unnecessary image data at the edge of the document when the document is read, it is not possible to distinguish between unnecessary image data and necessary image data. For this reason, even if erasing is performed for the purpose of erasing unnecessary image data, there is a possibility of erasing even necessary image data. In addition, since the cause of unnecessary image data varies depending on the document reading method, there is a problem that in setting the erase width from the document edge, the optimum erase width also varies depending on the reading method.
Further, when the original is read, unnecessary image data at the edge of the original is generated in different widths if the cause of the occurrence is different. Because the causes that occur at the top, bottom, right, and left edges of the document are different, optimal erasure cannot be performed by erasing the same width while erasing unnecessary image data while minimizing the erasure of necessary image data. There is a problem.
An object of the present invention is to provide an image forming apparatus capable of optimally erasing unnecessary image data for each reading method.

In order to achieve the above object, the invention described in claim 1 includes an erasing range based on the document edge (first erasing range) and an erasing range based on the contact glass edge (second erasing range). ) Can be independently set, storage means for storing the first erasing range and the second erasing range set by the operating means, and a sheet-through automatic document feeder In the case of the copying operation used, the image data in the first erasing range stored in the storage means is erased with reference to the edge of the document, and the copying operation without using the sheet-through automatic document feeder is used. In this case, an image forming apparatus including a mask processing unit for erasing image data in the second erasure range stored in the storage unit with a contact glass edge as a reference is the main feature.
According to a second aspect of the present invention, in the setting of the erasing range based on the document edge and the erasing range based on the contact glass edge, the operation means sets the upper end, lower end, right end and left end ranges, respectively. It can be set independently.

In the case of a copying operation using a sheet-through type automatic document feeder, the present invention deletes image data with reference to the edge of the document, and a copying operation without using a sheet-through type automatic document feeder. Since the image data is erased with the contact glass edge as a reference, unnecessary image data can be erased optimally for each reading method.
In addition, the erasing width based on the document edge and the erasing width based on the contact glass edge can be set independently, so that unnecessary image data can be erased optimally for each scanning method. it can.
Further, since the erase width can be set independently at the upper end, the lower end, the right end, and the left end, unnecessary image data can be erased optimally for each reading method.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic block diagram of an image forming apparatus according to an embodiment of the present invention. The image input unit 101 corresponds to a digital copying machine or a digital facsimile scanner, reads a document, and sends it to the image processing unit 102 as input image data. The image processing unit 102 performs various image processing such as MTF filter processing, mask processing, γ conversion processing, and gradation processing on the input image data, and sends the processed image data to the image output unit 103. The image output unit 103 corresponds to a printer of a digital copying machine, and prints out image data after image processing on paper.
The control unit 104 performs overall control of the apparatus. The image input unit 101 performs scanner operation control, and the image processing unit 102 sets parameters used for various image processing such as MTF filter processing, mask processing, γ correction processing, and gradation processing. The image output unit 103 performs printer operation control, and the operation unit 105 performs various information display control and operation mode input control. The operation unit 105 is used to input an operation mode set by the user and a copy start instruction.
FIG. 2 is a detailed block diagram of the image forming apparatus according to the embodiment of the present invention. The image processing unit 102 includes an MTF filter processing unit 201 that performs a filtering process on the image data scanned by the image input unit 101, a mask processing unit 202 that deletes a specified area, and a γ that adjusts the density of output image data. A correction processing unit 203 and a gradation processing unit 204 are provided.
The control unit 104 includes a CPU 205 that controls the entire apparatus, a ROM 206 that stores a control program, and a RAM 207 that is temporarily used by the control program. Each unit is connected by an internal system bus 208 that exchanges data with each other.
Next, the flow of image data processing will be described. The image data read by the image input unit 101 is subjected to enhancement processing by the MTF filter processing unit 201, the area designated by the mask processing unit 202 is deleted, and the density adjustment of the output image is performed by the γ conversion processing unit 203. In the gradation processing unit 204, the image output unit 103 processes the image data having a gradation suitable for output. Since the MTF filter processing unit 201, the γ conversion processing unit 203, and the gradation processing unit 204 are the same as those in the prior art, detailed description thereof is omitted.

Next, the configuration of the mask processing unit 203 will be described. FIG. 3 is a detailed block diagram of the mask processing unit 203. Image data from the MTF filter processing unit 201 is sent to the γ conversion processing unit 203 through the gate 310. At this time, when the EN of the gate 310 is in the enabled state, the image data is passed as it is, and when it is in the disabled state, 0 is output without passing the image data. The image data is erased by outputting 0 from the gate 310.
The start coordinate position and end coordinate position of erasure are sent from the system bus 208 to the F / Fs 301, 302, 305 and 306. F / F 301 has a coordinate position corresponding to X1 in FIG. 10 described later, F / F 302 has a coordinate position corresponding to X2, F / F 305 has a coordinate position corresponding to Y1, and F / F 306 has Y2 The coordinate positions corresponding to are respectively stored.
The main scanning counter 303 counts for each pixel, and sends the main scanning coordinate position to the comparator 304. The comparator 304 compares the coordinate position X1 sent from the F / F 301 with the coordinate position X2 sent from the F / F 302 and the coordinate position sent from the main scanning counter 303, and the coordinate position of the main scanning is determined. If it is between X1 and X2, “1” is output, otherwise “0” is output.
The sub-scanning counter 307 counts for each line and sends the sub-scanning coordinate position to the comparator 308. The comparator 308 compares the coordinate position Y1 sent from the F / F 305 with the coordinate position Y2 sent from the F / F 306 and the coordinate position sent from the sub-scanning counter 307, and the coordinate position of the sub-scan is determined. If it is between Y1 and Y2, “1” is output, otherwise “0” is output.
The AND 309 sends the logical product of the outputs of the comparator 304 and the comparator 308 to the EN of the gate 310. The AND 309 outputs “1” when both the comparator 304 and the comparator 308 output “1”. At this time, the gate 310 is enabled, and the image data is sent to the γ conversion processing unit 203. When the output of the AND 309 is “0”, the gate 310 is disabled and the image data is erased.
FIG. 4 is a diagram showing an example of an operation unit screen for adjusting the erasure width based on the document size. The erase width set here is stored in the RAM 207, and is used as an erase width designated in advance during a reading operation using a sheet-through automatic document feeder.

FIG. 5 is a diagram showing an example of an operation unit screen for adjusting the contact glass reference erase width. The erase width set here is stored in the RAM 207 and used as an erase width designated in advance during a reading operation without using the sheet-through automatic document feeder.
A digital copying machine to which the present invention is applied will be described with reference to FIGS. FIG. 6 shows a sheet-through type automatic document feeder. The document is placed on the document table so that the reading surface faces upward. The reference for placing the document is based on the reading origin 601. The document size detection sensor 602 detects the size of the document in a state where the document is placed and conveyed to the reading start position. In reading a document using a sheet-through type automatic document feeder, reading is performed by conveying the document in a state where a reading optical unit (units 903 to 908 shown in FIG. 9 described later) is fixed.
FIG. 7 is a diagram showing the configuration of the reading document table. The document is placed on the document table so that the reading surface faces downward. Reading is performed with reference to the reading origin 701 on the document table. A document size detection sensor 702 detects the size of the document placed on the document table.
FIG. 8 is a diagram showing a read document and a reading scanning direction. The origin of the read original is placed at the upper left of the original in accordance with the read origin 901 on the original table. The main scanning of the reading surface of the document is electronically performed by the CCD image sensor 908, and line data L1, L2, L3,. Scanning in the sub-scanning direction is mechanically performed by relative movement between the document and the CCD image sensor 908.
FIG. 9 is a diagram showing the configuration of the reading optical system. The reading surface of the original is illuminated by a light source 903 extending in the main scanning direction, and the reflected light is sequentially reflected by a first mirror 904, a second mirror 905, and a third mirror 906, and is coupled onto a CCD image sensor 908 by a lens 907. It is imaged and read.

  Next, erasing of image data in the present invention will be described with reference to FIG. When erasing the image data, the image data at the edge of the document is erased as shown by the shaded portion in FIG. In the main scanning direction, erasure is performed from the front end of the image data to the position of the coordinate X1, and from the coordinate X2 to the rear end of the image data. In the sub-scanning direction, erasure is performed from the front end of the image data to the position of the coordinate Y1, and erasure is performed from the coordinate Y2 to the rear end of the image data.

In the first embodiment, the coordinate values set in the F / Fs 301, 302, 305, and 306 are different between the reading operation using the sheet-through type automatic document feeder and the other reading operations. In the case of a reading operation using a sheet-through type automatic document feeder, the document size detected by the document size detection sensor 602 is taken as an outer shape, and image data is erased from the edge with a predetermined erase width. The coordinates of F / F 301, 302, 305, 306 are set in.
For scanning operations that do not use the sheet-through automatic document feeder, the maximum value of the effective image reading range on the contact glass is defined as the outer shape regardless of the size of the document, and the erase width is specified in advance from the edge. The coordinates of the F / Fs 301, 302, 305, and 306 are set so as to erase the image data.

  The erasure width used in the reading operation using the sheet-through type automatic document feeder and the erasing width used in the reading operation without using the sheet-through type automatic document feeder are respectively independent of the RAM 207. Is remembered within.

  FIG. 4 and FIG. 5 are examples of the operation unit screen for adjusting the erase width. Here, the width of the erase from the document edge can be set independently from the erase width from the upper end, the erase width from the lower end, the erase width from the right end, and the erase width from the left end. Coordinates set in the F / Fs 301, 302, 305, and 306 are calculated based on the erase width set here.

1 is a schematic block diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a detailed block diagram of an image forming apparatus according to an embodiment of the present invention. The block diagram of a mask process part. FIG. 10 is a diagram showing an example of a screen of an operation unit for setting an erase width based on a document size. The figure which shows the example of a screen of the operation part which sets the erasing width of a contact glass reference | standard. 1 is a diagram illustrating a sheet-through type automatic document feeder. FIG. 1 is a diagram showing a document table of a digital copying machine. The figure which shows the direction which scans a document. 1 is a diagram illustrating a configuration of a reading optical system of a digital copying machine. FIG. 4 is a diagram showing a range in which image data is erased from a document edge.

Explanation of symbols

104 Control unit (control means)
105 Operation unit (operation means)
202 Mask processing unit (mask processing means)

Claims (2)

An operating means capable of independently setting an erasing range based on the document edge (hereinafter referred to as a first erasing range) and an erasing range based on the contact glass edge (hereinafter referred to as a second erasing range); ,
Storage means for storing each of the first erasure range and the second erasure range set by the operation means;
In the case of a copying operation using a sheet-through type automatic document feeder, the image data in the first erasure range stored in the storage means is erased with reference to the document edge, and a sheet-through type original is obtained. In the case of a copying operation that does not use an automatic feeding device, mask processing means for erasing the image data in the second erasure range stored in the storage means with reference to the edge of the contact glass;
An image forming apparatus comprising: In the setting of the erasing range based on the document edge and the erasing range based on the contact glass edge, the operation means can set the upper end, lower end, right end, and left end ranges independently. The image forming apparatus according to claim 1, wherein:

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