JP2000203103A - Image data processor for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print out a high resolution data without lowering the image quality while reducing the capacity of a page memory for storing an image data. SOLUTION: An image data processor for printer comprises an interface 101 for receiving an image data, a memory 103 for storing the received image data temporarily, a memory control circuit 102, and an engine interface 104 for supplying a print engine 105 with a data required for printing wherein the memory control circuit 102 supplies the print engine 105 with an image data from the memory 103 in synchronism with the print engine 105 when printing is conducted and stores the received image data optionally in the memory area of the memory 103 where the outputted image data had been stored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data processing apparatus for a monochrome or color printer, and more particularly to an image data processing apparatus for a printer which can be suitably applied to digital image forming apparatuses such as digital copying machines and facsimile machines.

[0002]

2. Description of the Related Art In an image data processing apparatus for a printer of this type, when a print engine operates at a constant speed,
Image data must be supplied to the print engine at a constant speed corresponding to the process speed of the print engine. Therefore, when the data transfer speed between the host computer and the printer is slower than the print speed or the required transfer speed is not guaranteed, it is necessary to supply data to the print engine at a constant speed by more than one page. Is temporarily stored in the page memory, and the image data is supplied to the image forming process at a constant speed. FIG. 18 shows a configuration example of a conventional page printer. The capacity of the memory inside the printer in FIG. 18 is the same as the image data amount for one page.

In recent years, as the color, resolution, and gradation of page printers have increased, the capacity of page memories for storing image data has been increasing, leading to an increase in the cost of the apparatus. Various proposals have been made to solve this problem. For example, in the technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-278263, a means for storing image information for a plurality of lines in the main scanning direction and an image of a recording pixel and its peripheral pixels from a group of image information stored therein are provided. A method of electronically generating a high-resolution image from a low-resolution image by providing means for referring to information is proposed.

[0004]

However, in the above prior art, satisfactory results cannot always be obtained in terms of faithfully reproducing high-resolution data. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems in the conventional technology, to print high-resolution data without deteriorating the image quality, and to increase the capacity of a page memory for storing image data. An object of the present invention is to provide an image data processing device of a printer which can be reduced.

More specifically, according to the first aspect of the present invention, the capacity of a page memory is reduced in an image data processing apparatus of a printer that prints high-resolution image data input from a host computer without deteriorating the data. The purpose is to: Further, in the method according to the first aspect, since the read / write to the memory is performed during the operation of the print engine, the load on the memory control circuit is taken into consideration. It is another object of the present invention to further reduce the load on the memory control circuit while reducing the load. Furthermore, in the method according to the first and second aspects, in view of the fact that an output image is not printed from the middle or a part of the output image is dropped when the data transfer cannot be synchronized with the print engine, The fourth object of the present invention is to provide an image data processing apparatus of a printer capable of preventing a loss of an output image even when data transfer cannot be synchronized with a print engine.

[0006]

In order to achieve the above object, in an image data processing apparatus for a printer according to the present invention, an interface for receiving image data is provided.
01 and a memory 10 for temporarily storing received image data.
3, a memory control circuit 102, and an engine interface 104 for supplying data required for printing to a print engine 105.
During printing, the image data is supplied from the memory 103 to the print engine 105 in synchronization with the print engine 105, and the received image is stored in the memory area of the memory 103 where the output image data is stored. Data is stored as needed.

Further, in the image data processing apparatus for a printer according to the second aspect of the present invention, data (preceding data) selected at regular intervals from the entire image data on the host device side.
, An interface 201 for separately receiving unselected data (subsequent data), a memory 206 for temporarily storing preceding data, a memory control circuit 202, and print data from the preceding data and subsequent data in real time. A print data generation circuit 203 for generating the print data and an engine interface 204 for supplying data necessary for printing to a print engine 205 are provided.

According to a third aspect of the present invention, there is provided an image data processing apparatus for a printer, further comprising an image loss prevention circuit 307 in addition to the configuration according to the second aspect, wherein the image loss prevention circuit 307 is provided with A function of determining whether data can be synchronized with the print engine 205, and normally outputting the preceding data and subsequent data directly to the engine interface 304, but when it is determined that the subsequent data cannot be synchronized with the print engine. And outputting missing prevention data generated based on the preceding data instead of the succeeding data.

Further, in the image data processing apparatus for a printer according to the present invention, when the image data is an image of a multi-value gradation, the gradation of the data is converted into an upper bit and a lower bit on the upper device side. An interface 301 for separately receiving upper bit image data (preceding data) and lower bit image data (subsequent data), a memory 306 for temporarily storing preceding data, a memory control circuit 302, A print data generation circuit 303 for generating print data in real time from preceding data and subsequent data; an engine interface 304 for supplying data necessary for printing to a print engine 305; and an image loss prevention circuit 307. Circuit 3
07 normally outputs the preceding data and the succeeding data to the engine interface 304 as they are, but outputs only the preceding data when it is determined that the reception of the following data is not in time.

In the image data processing apparatus for a printer according to the first aspect of the present invention, in parallel with the operation of supplying data to the print engine, data which cannot be stored in the memory among all the images of one page is output to the memory area where the data has been output. , The necessary memory capacity can be reduced.
Further, it is possible to faithfully print the image data input from the host without deteriorating. Further, in the image data processing apparatus for a printer according to the second aspect of the present invention, a memory for storing the following data is not required, so that the required memory capacity can be reduced. Further, during the operation of the print engine 205, no image is written to the memory 206, so that the load on the memory control circuit 202 is reduced.

Further, in the image data processing device for a printer according to the third aspect of the present invention, even if the subsequent data cannot be synchronized with the print engine, it is possible to obtain an image without any loss. Further, in the image data processing apparatus for a printer according to the fourth aspect of the present invention, even when the subsequent data cannot be synchronized with the print engine, it is possible to obtain an output image which maintains the resolution of the input image from the host.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described.
A detailed description will be given based on a preferred embodiment shown in the drawings. FIG.
FIG. 1 is a block diagram showing a schematic configuration of a page printer according to a first embodiment of the present invention, and corresponds to claim 1. The page printer 106 according to the present embodiment includes:
The system is configured by being connected to a host computer (not shown). In FIG. 1, 101 is a printer interface, 102 is a memory control circuit, 103
Denotes a memory, 104 denotes a (print) engine interface, and 105 denotes a print engine.

FIG. 2 shows the memory 103 in this embodiment. Memory 103 inside page printer in FIG.
Is smaller than the amount of image data for one page. Compared with the conventional page printer shown in FIG.
The capacity of No. 3 has been greatly reduced from what was conventionally the same as the amount of image data for one page. 3 and 4 show the operation sequence of image formation according to the present embodiment. Although FIGS. 3 and 4 are originally a single sheet, they are shown in two sheets due to space limitations. The operation sequence of image formation will be described below with reference to FIGS.

First, before starting printing, as shown in FIG. 3A, the image data is divided into two parts in the memory 100 of the host computer, one for the first transfer and the second for the transfer. deep. At the start of printing, FIG.
(B) As shown in FIG.
From 0, the divided image data to be transferred first is
The data is transferred to the memory 103 in the page printer 106 and stored. As shown in FIG. 3B, when the divided image data to be transferred first is stored in the memory 103, the memory control circuit 102 supplies the image data from the memory 103 to the print engine 105, Print Engine 1
05 starts printing.

Then, as shown in FIG. 4A, by supplying image data from the memory 103 to the engine 105, a memory area in the memory 103 which has been output is generated. By storing image data newly transferred (to be transferred later) in this area, FIG.
As shown in (b), all image data can be printed. Here, the required capacity of the memory 103 is
It is determined by the data capacity of the image to be printed, the print speed of the engine, and the transfer speed between the printer and the host. The image data to be transferred later must go through the process of transferring from the host to the printer, writing to the memory in the printer, and reading from the memory to the printer engine during image formation.

The image data transferred later must be of a size that allows these steps to be completed during image formation. Thereby, the memory 10 in the printer is
3 are determined. According to the present embodiment, the necessary memory capacity can be reduced by sequentially transferring the next image data to the output memory area in parallel with the operation of supplying the image data to the print engine 105. Further, it is possible to faithfully print the image data input from the host without deteriorating. In this embodiment, the image data used may be a bitmap or compressed data. However, when the compressed data is used, a decompression circuit is required between the printer interface 101 and the memory control circuit 102.

Next, an embodiment corresponding to claim 2 will be described. In the present embodiment, as shown in FIG.
07 and a host computer 208. The host computer 208 includes a dividing unit 200 for dividing image data, which will be described later. The configuration of the page printer 207 is the same as that shown in the first embodiment. 201 is a printer interface, 202 is a memory control circuit, 206 is a memory, 204 is a (print) engine interface, and 205 is a print engine. Reference numeral 203 denotes a print data generation circuit that generates print data from image data output from the memory control circuit 202 and image data output from the printer interface 201.

FIGS. 6 and 7 show a method of dividing and transferring image data in this embodiment. In this embodiment,
The image data developed in the memory in the host computer 207 is divided by the dividing means 200 as shown in FIG.
Divide in the main scanning direction. From the image data divided in the main scanning direction, an arbitrary ratio of image data
10, and the remaining image data is referred to as subsequent data 211. The ratio of this data division selection depends on the printer engine,
Determined by transfer speed and memory size. As shown in FIG. 7, the image data divided as described above is obtained by first transferring the preceding data 210 to the memory 206,
In accordance with the timing at which the preceding data 210 is output from the memory 206, the following data 2
11 is output.

FIGS. 8 and 9 show the operation sequence of image formation according to the present invention. Hereinafter, the operation sequence of the image formation will be described with reference to FIG. 6, FIG. 8, and FIG. Before starting image formation,
As shown in FIGS. 6 and 8A, the preceding data 210 is stored in the memory 206 in the printer. Then, at the time of image formation, as shown in FIG. 8B, the following data 211 is received by the printer interface. The preceding data 21 stored in the memory 206 by the print data generation circuit 203
0 and the succeeding data 211 to restore the original image (see FIGS. 6 and 9),
05.

According to the present embodiment, since a memory for storing the succeeding data is not required, the required memory capacity can be reduced. During the operation of the print engine 205, the memory 20
6, no image is written to the memory control circuit 202.
The load of the lightens. Further, it is possible to faithfully print the image data input from the host without deteriorating. In the present embodiment, the image is divided in the main scanning direction to obtain the preceding data and the following data, but another dividing method may be used. In this embodiment, the image data used may be a bitmap or compressed data. However, when compressed data is used, a decompression circuit is required between the printer interface and the memory control circuit.

Hereinafter, an embodiment corresponding to claim 3 will be described. The present embodiment includes a page printer 308 and a host computer 309, as shown in FIG. The host computer 309 includes a dividing unit 300 that divides image data, which will be described later. The configuration of the page printer 308 is the same as that shown in the first and second embodiments. 301 is a printer interface, 302 is a memory control circuit, 306 is a memory, 303 is a print data generation circuit, and 304 is a (print) engine interface. , 305 indicate a print engine.
307 normally outputs the preceding data 210 and the succeeding data 211 as they are, but if it is determined that the succeeding data cannot be synchronized with the print engine, the preceding data 210
5 shows an image defect prevention circuit which outputs the same data as the following data instead of the subsequent data 211.

FIGS. 11 and 12 show a method of dividing and transferring image data in the present embodiment. In the present invention, an image is divided in the main scanning direction as in the embodiment of the present invention, and odd-numbered columns of scanning lines are used as preceding data, and even-numbered columns are used as following data. Here, as shown in FIG. 12, when the preceding data and the following data have the same capacity, as shown in FIG. 14, when the preceding data and the following data have different capacities, they are divided. FIG. 13 shows the operation of the image loss prevention circuit 307 in this embodiment. FIG. 13 corresponds to FIG. 12, that is, the case where the preceding data and the succeeding data have the same capacity.
1 is output as it is (see FIG. 13A).

On the other hand, the following data is the print engine 30.
When it is determined that the data cannot be synchronized with No. 5, the image loss prevention circuit 307 outputs the same data as the preceding data 310 instead of the succeeding data 311 (FIG. 13B). That is, after the time when it is determined that the subsequent data cannot be synchronized with the print engine 305, only the preceding data is output (see FIG. 12). In the above-described embodiment, since the capacities of the preceding data and the following data are the same, the image loss prevention circuit 307
Output the same data as the preceding data in place of the succeeding data 311. However, if the capacities of the preceding data and the succeeding data are different, the image loss prevention circuit 307 performs the processing described below.

As shown in FIG. 14, if the preceding data and the succeeding data have different capacities in the main scanning direction, the image missing circuit 307 repeats the last line of the preceding data to generate missing prevention data. , Instead of trailing data. Also in the case of the present embodiment, since a memory for storing the succeeding data is not required, the required memory capacity can be reduced. During the operation of the print engine 205, the memory 20
6, no image is written to the memory control circuit 202.
The load of the lightens. Further, it is possible to faithfully print the image data input from the host without deteriorating. In the present embodiment, the image is divided in the main scanning direction to obtain the preceding data and the following data, but another dividing method may be used.

Next, an embodiment corresponding to claim 4 will be described. This embodiment has a completely same hardware configuration as that of the third embodiment. That is, the printer 30
8 and a host computer 309. Claim 3
The difference from the embodiment corresponding to the first embodiment is in the method of dividing the image data by the dividing means 300 in the host computer 309 and the operation of the image loss prevention circuit 307 as described later. The method of dividing the image data by the dividing means 300 in this embodiment is such that the preceding data is an image with a higher gradation and the succeeding data is an image with a lower gradation. FIG. 17 shows a method of dividing image data, a method of transferring the image data, and a timing of printing in this embodiment.

FIG. 16 shows the operation of the image loss prevention circuit 307 in this embodiment. Normally, as in the case of the third aspect, the upper gradation data and the lower gradation data are output as they are (see FIG. 16A). If the printer interface 304 determines that the lower-level data is slower than the speed at which the data can be synchronized with the print engine 305, the image loss prevention circuit 307 outputs only the higher-level data (see FIG. 16B). As a result, after it is determined that the subsequent data cannot be synchronized with the print engine 305, print data of low gradation using only preceding data of higher gradation is output.

Also in the case of the present embodiment, since a memory for storing the succeeding data is not required, the required memory capacity can be reduced. Also, since no image is written to the memory 206 during the operation of the print engine 205, the memory control circuit 2
02 becomes lighter. Further, the image data input from the host can be faithfully printed without deteriorating. In addition,
In the present embodiment, the image is divided in the main scanning direction to obtain the preceding data and the succeeding data, but another dividing method may be used. Note that the above embodiment is an example of the present invention, and it goes without saying that the present invention is not limited to this.

[0028]

As described above in detail, according to the present invention, high-resolution data can be printed without deteriorating the image quality, and the capacity of the page memory for storing the image data is improved. This has a remarkable effect that an image data processing device of a printer capable of reducing the image quality can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a page printer according to a first embodiment.

FIG. 2 is a configuration diagram of a memory of the page printer according to the first embodiment.

FIG. 3 is an explanatory diagram of an image forming operation sequence (part 1) of the page printer according to the first embodiment.

FIG. 4 is an explanatory diagram of an image forming operation sequence (part 2) of the page printer according to the first embodiment.

FIG. 5 is a configuration diagram of a page printer according to a second embodiment.

FIG. 6 is a diagram illustrating data transfer and print timings of a page printer according to a second embodiment.

FIG. 7 is a diagram illustrating an example of a method of extracting image data in a page printer according to a second embodiment.

FIG. 8 is an explanatory diagram of an image forming operation sequence (part 1) of the page printer according to the second embodiment.

FIG. 9 is an explanatory diagram of an image forming operation sequence (part 2) of the page printer according to the second embodiment.

FIG. 10 is a configuration diagram of a page printer according to a third embodiment.

FIG. 11 is a diagram illustrating timings of data transfer and printing in the page printer according to the third embodiment.

FIG. 12 is a diagram illustrating an example of image division in a page printer according to a third embodiment.

FIG. 13 is an operation explanatory diagram of an image loss prevention circuit in a page printer according to a third embodiment.

FIG. 14 is a diagram illustrating an example of division of an image in a page printer according to a third embodiment (when the capacities of preceding data and subsequent data are different).

FIG. 15 is a diagram illustrating the operation of an image loss prevention circuit in the page printer according to the third embodiment.

FIG. 16 is a diagram illustrating the operation of an image loss prevention circuit in a page printer according to a fourth embodiment.

FIG. 17 is a diagram illustrating timings of data transfer and printing in the page printer according to the fourth embodiment.

FIG. 18 is a diagram illustrating a configuration of a conventional page printer.

[Explanation of symbols]

 101, 201, 301 Printer interface 102, 202, 302 Memory control circuit 103, 206, 306 Memory 104, 204, 304 Engine interface 105, 205, 305 Print engine 106, 207, 308 Printer 200, 300 Dividing means 203, 303 Print Data generation circuit 208, 309 Host computer 210, 310 Preceding data 211, 311 Subsequent data 307 Image loss prevention circuit

Claims (4)

[Claims] An interface for receiving image data, a memory for temporarily storing the received image data, a memory control circuit, and an engine interface for supplying data necessary for printing to a print engine; During printing, image data is supplied from the memory to the print engine in synchronization with the print engine, and the received image data is stored in the memory area of the memory where the output image data is stored as needed. An image data processing device for a printer. 2. An interface for separately receiving data (preceding data) selected at predetermined intervals from the entire image data and unselected data (subsequent data) on the host device side, and temporarily stores the preceding data. A memory for storing data, a memory control circuit, a print data generating circuit for generating print data in real time from the preceding data and the following data, and an engine interface for supplying data necessary for printing to a print engine. An image data processing device for a printer. 3. An image missing prevention circuit in addition to each of the above means, wherein the image missing prevention circuit determines whether or not the subsequent data can be synchronized with the print engine, and the image missing prevention circuit usually includes And outputting the subsequent data as it is to the engine interface, and when it is determined that the subsequent data cannot be synchronized with the print engine, outputting missing prevention data generated based on the preceding data instead of the subsequent data. 3. An image data processing apparatus for a printer according to claim 2, wherein: 4. When the image data is an image of a multi-level gradation, the higher-level device divides the gradation of the data into upper bits and lower bits, and outputs the upper bit image data (preceding data) and the lower bits. An interface for separately receiving image data (subsequent data), a memory for temporarily storing the preceding data, a memory control circuit, and a print data generating circuit for generating print data in real time from the preceding data and subsequent data And an engine interface for supplying data necessary for printing to the print engine, and an image loss prevention circuit, wherein the image loss prevention circuit includes:
Normally, the preceding data and the following data are output to the engine interface as they are, and if it is determined that the reception of the following data is not in time, only the preceding data is output, and Processing equipment.