JPH07285238A - Image forming device - Google Patents

Abstract

PURPOSE:To regenerate an image of always optimally high-quality regardless of the type of an image. CONSTITUTION:An image forming device is composed of an ROS device which records an image on a recording sheet based on input image data, a text.figure synthesizing area identification part 4 which divides an image to be recorded into areas in accordance with the type of an image and dispatches an area identification signal, a CPU which changes the intensity of a laser beam in the ROS device 11 based on the area identification signal obtained from the identification part 4 when recording an image on a recording sheet using the ROS device 11, and an ROS control part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser printer capable of changing print parameters according to the type of image to be output.

[0002]

2. Description of the Related Art For example, in an electrophotographic laser printer, an image is formed on a recording paper by each process of charging, exposing, developing, transferring and fixing. The images to be output include binary images such as characters, halftone images, and halftone images such as photographs. However, since the image recording conditions differ depending on the type of image, the image forming conditions are fixed. However, the image quality may be deteriorated. In order to prevent this, print parameters are manually changed according to the type of image to be output. For example, JP-A-4-2742
Japanese Patent Laid-Open No. 62-26471 and Japanese Patent Laid-Open No. 4-204671 disclose an image forming apparatus in which a user can variously change the intensity of a laser beam within a range that does not deteriorate image quality.

[0003]

However, in the apparatus described in the above publication, the user has to manually adjust the intensity of the laser beam for various images.
There is a problem that the operation becomes complicated.

Therefore, an object of the present invention is to always reproduce an image of optimum image quality regardless of the type of image.

[0005]

In order to achieve the above object, the present invention provides a recording means for recording an image on a recording paper based on input image data, and a plurality of images to be recorded according to the type of the image. Area separating means for generating an area identifying signal by separating into areas, and a printing parameter in the recording means based on the area identifying signal obtained by the area separating means when an image is recorded on a recording paper by the recording means. And a print parameter control unit for changing the print parameter.

[0006]

The type of the image area is identified based on the input image data, and the print parameter is changed according to the type of the image area. For example, when the recording means uses a laser, the intensity of the laser beam is switched for each area depending on whether the image type is text or line drawing, and the image in each area is optimal. It is formed under the printing conditions.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the present invention will be specifically described below based on embodiments with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the image forming apparatus of the present invention. The image data from the host device 1 is supplied to the image output unit 3 via the image processing unit 2, and the image corresponding to the image data is output on the recording paper. In the present embodiment, structured image data is used as the image data from the host device 1, and one image has a text area, a graphic area, a text area, a graphic area, and a base area corresponding to the background. It is configured by combining bit map areas and the like.

The image processing section 2 includes a text / graphic synthesis area recognition section 4 for analyzing image data input from the host device 1 and outputting area coordinate / area identifier / composition order data. Note that the image processing unit 2 also includes other processing blocks, but here, only the portions related to the present invention will be described, and description of the other portions will be omitted.

FIG. 2 shows a text / graphic synthesis area recognition unit 4
3 is a block diagram showing the details of FIG. The text / graphic synthesis region recognition unit 4 analyzes the input structured image data, identifies each region T0 to Tn, and outputs information about each region T0 to Tn, and each of these regions. Area T0
To a plurality of area information holding units 6 that hold information about Tn
And are provided.

FIG. 3 is a schematic flowchart showing the processing in the area identifying section 5. First, the base area T0 in the image data is determined, and whether the base area T0 is a text area or a graphic area is determined.
(Step 101). The determination result of the type of the area is used to control the exposure intensity in the raster output scanning unit described later. Next, for each of the areas T1 to Tn, the coordinates of the frame of each area in the recording paper to be printed are obtained (step 102). Next, it is determined whether the area within the coordinate point is a text frame or a graphic frame, and a corresponding area identifier is generated (step 103). Next, it is judged which position the area within the coordinate point is located from the base area T0, and the combining order is obtained (step 104). The processes of steps 102 to 104 are performed for all the areas T0 to Tn. Finally, the data of the area coordinates, the area identifier, and the combination order obtained as described above are transmitted to the image output unit 3 as one area / one package separately from the image data. For example, the region T
In the case of 0 to Tn, n packages are output.

FIG. 4 is an explanatory view schematically showing the relationship between the areas. The figure (a) shows the up-and-down relationship of the rank of each area | region, and the figure (b) shows the positional relationship on the plane of each area | region. In the example shown in FIG. 4, areas T1, T2, and T3 are sequentially arranged on the base area T0 to form a composite image. That is, in this case, the composition order for the base region T0 is in the order of the regions T1, T2, and T3.

As described above, the area identification unit 5 outputs area information including the coordinates, identifiers, and combining order of the areas T0 to Tn, and the area information is held in each area information holding unit 6. From the text / graphic synthesis area recognition unit 4,
It is output to the image output unit 3 as area coordinates / area identifier / composition order data.

The image output section 3 comprises a main control section 7 and a raster output scanning (indicated by ROS in the figure) unit 8.
The main control unit 7 is a CPU 9 that controls the overall operation of the image output unit 3.
And the area coordinates from the text / figure composition area recognition unit 4 /
An application-specific integrated circuit for ROS control (RO in the figure) for receiving a region identifier / composition order data and performing a predetermined process.
S ASIC) 10). Further, the raster output scanning unit 8 modulates the exposure amount of laser light in the raster output scanning device 11 based on the value of the raster output scanning device 11 including a laser, a rotary polygon mirror, a lens, and the supplied image data. In addition, a raster output scanning control unit 12 that controls the exposure amount of the laser light according to the area based on an instruction from the CPU 9 is provided.

The area coordinates / area identifier / composition order data from the text / figure composition area recognition unit 4 is used together with the image data in the application specific integrated circuit 1 for ROS control of the main control unit 7.
Supplied to zero. Application specific integrated circuit 10 for ROS control
The image data from the raster output scanning control unit 12 is supplied to the raster output scanning device 11 according to the value of the image data.
The exposure amount of the laser light in is modulated. Also, CPU
Laser intensity setting data for switching the intensity of the laser beam in the raster output scanning device 11 is transmitted in serial data format from the raster output scanning controller 12 to the raster output scanning controller 12, and is read into the raster output scanning controller 12 at the timing of the latch signal.

For example, when the image data has a data structure as shown in FIG. 4, the base area T0 is scanned immediately after the start of scanning, and depending on whether this area is a text area or a graphic area, The laser intensity setting data is changed, so that the intensity of the laser light is switched. For example, if it is a text area,
The intensity of the laser light is increased to clearly reproduce black and white, and the intensity of the laser light is decreased to reproduce a thin line in the figure area. Information regarding each area such as where the laser light is scanning, what kind of area is being scanned, or what is the composition order is synchronized with the scanning position. This can be known by referring to the area coordinates / area identifier / composition order data from the text / graphic composition area recognition unit 4.

When the scanning progresses to reach the coordinate points of the frame of another area, the area identifier of that area is referred to and the intensity of the laser beam is newly set. At this time, if the newly scanned area overlaps with another area, the combining order is referred to, and the intensity of the laser beam is controlled based on the highest order area.

In the above embodiment, the intensity of the laser beam was used as an example of the print parameter for explanation.
It is not limited to this, other printing parameters,
For example, in an image forming apparatus that employs an electrophotographic method, the developing voltage and the like may be controlled. However, in this case, control is performed in line units.

[0019]

As described above, in the present invention, the print parameters are automatically changed according to the area of the image, so that the image of the optimum image quality can always be obtained regardless of the type of the image. It can be reproduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a block diagram showing details of a text / graphic synthesis area recognition unit.

FIG. 3 is a schematic flowchart showing a process in an area identification unit.

FIG. 4 is an explanatory diagram schematically showing the relationship between regions.

[Explanation of symbols]

1 ... Host device, 2 ... Image processing unit, 3 ... Image output unit, 4
... text / graphic composition area recognition unit, 5 ... area identification unit, 6
... area information holding unit, 7 ... main control unit, 8 ... raster output scanning unit, 9 ... CPU, 10 ... application specific integrated circuit for ROS control, 11 ... raster output scanning device, 12 ... raster output scanning control unit

Claims (1)

[Claims] 1. Recording means for recording an image on recording paper based on input image data, and area separation means for separating an image to be recorded into a plurality of areas according to the type of image to generate an area identification signal. A print parameter control unit that changes a print parameter in the recording unit based on an area identification signal obtained by the area separating unit when an image is recorded on a recording sheet by the recording unit. Image forming apparatus.