JPH11165429A - Electrophotographic printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive electrophotographic printer in which the resolution converting ratio can be adjusted even if the resolution of the printer is different fractionally from a designated resolution. SOLUTION: An electrophotographic printer comprises a control section 4 for receiving a data from a host computer 1, a butter 9 for storing the receiving data, a section 5 for analyzing the receiving data, a writing section 7 for generating a bit map data of actual print format based on the analyzed data, an image buffer 11 for storing the generated bit map data, and an output control section 8 for transmitting a data in the image buffer to a print mechanism section 3 wherein a decision is made, at a resolution conversion control section 6 whether a logical resolution designated by the host computer 1 matches the physical resolution at the print mechanism section. If they do not match each other, setting is switched between print output through resolution conversion at the resolution conversion control section 6 and print output not through resolution conversion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printer capable of logically converting data from a host computer into a designated resolution and printing the same, and more particularly, the designated resolution and the resolution of the printer are non-integer multiples. If different, it relates to an electrophotographic printer capable of adjusting the resolution conversion rate.

[0002]

2. Description of the Related Art Electrophotographic printers are widely used because they can print on plain paper with high resolution. Such an electrophotographic printer generally has a high resolution, and the resolution is fixed.

FIG. 5 is a block diagram of a control unit of an electrophotographic printer. Data transmitted from the host computer 1 is input to the printer control unit 2. The data is received by the reception control unit 4 and stored in the reception buffer 9. The data in the reception buffer is analyzed by the data analysis unit 5, the control data and print data are edited, converted into intermediate codes, and stored in the intermediate code buffer 10. That is,
The data analysis unit 5 analyzes the logical resolution designation control code from the host computer, performs resolution conversion processing so that the subsequent print data matches the physical resolution of the printer, and stores the generated print pattern data in the intermediate code buffer 10. I do. The drawing unit 7 generates bitmap data in print format based on the data read from the intermediate code buffer, and stores the data in the image buffer 11. The data in the image buffer is transferred to the printing mechanism unit 3 as video (hereinafter, referred to as VDO) data one dot line at a time when printing is started.

FIG. 6 is a diagram showing the configuration of a printing mechanism 3 of an electrophotographic printer. Photosensitive drum 24 having photoconductor on its surface
A charger 25, a developing device 26, a transfer device 27, a static elimination unit 28, and a cleaner 29 are arranged around the image forming apparatus to constitute an electrophotographic unit. Also, a laser diode 32,
Polygon mirror 33, spindle motor 34, lens 3
5 constitutes an exposure optical unit. The paper hopper 21, the pick roller 22, the transport roller 23, the fixing device 30, and the paper stacker 31 constitute a paper unit.

When printing is started, the photosensitive drum 24 and the spindle motor 34 start rotating, and the pick roller 22 rotates to start conveying the paper. The VDO data sent from the printer control unit 2 in FIG. 5 drives the laser diode 32 to form a latent image on the photosensitive drum. The latent image is developed by a developing device 26, transferred to a sheet by a transfer device 27, fixed by a fixing device 30, and discharged to a sheet stacker 31.

In such an electrophotographic printer, the resolution is determined by the paper transport speed, the polygon mirror rotation speed, and the VD
Determined by the modulation frequency of the O signal, these configurations are usually fixed and have a fixed resolution. In addition, application software operating on the host computer varies widely, and requests for printing data of various resolutions are generated. Therefore, when the resolution of the data transmitted from the host computer and the resolution of the printer are different, it is necessary to perform a resolution conversion process.

Conventionally, when such resolution conversion is required, the resolution conversion processing is logically performed by the printer control unit, or the resolution is physically converted by controlling the printing mechanism unit.

When the resolution conversion is logically performed by the printer control unit, the data is expanded / compressed on the memory of the control unit, and the data is transferred to the printing mechanism unit. FIG.
Shows a logical resolution conversion diagram. For example, if the resolution of the printer is 400 dpi (dots / inch) and the resolution of the data from the host computer is 200 dpi (dots / inch), the data (FIG. 3C) sent from the host computer is The image is enlarged twice in the horizontal direction and the vertical direction (FIG. 3A), logically decompressed, converted in resolution, and printed. If the resolution of the data from the host computer is higher than the resolution of the printer, the data is compressed.

When the resolution is physically converted by the printing mechanism, the paper transport speed, the polygon mirror rotation speed, and the modulation frequency of the VDO signal are configured to be variable, and are set in accordance with the required resolution. Printing was performed after changing the value. In this case, a structure for changing the diameter of the laser beam in order to correct the line width to be printed is also required.

[0010]

In the former method of the conventional method described above, when the resolution conversion is a non-integer multiple conversion rate, the result of actually printing the original data becomes dirty, and the print quality becomes poor. There was a problem of lowering. For example, if the physical resolution is 400 dpi and the logical resolution is 300 dpi
In the case of (dots / inch), the original data is printed by multiplying it by 4/3 so that only one dot out of three dots is enlarged.
As shown in (B), there is a problem that a printing result in which pattern unevenness occurs is caused.

In the latter method, a control circuit for changing the paper conveyance speed, the polygon mirror rotation speed, the modulation frequency of the VDO signal, and the laser beam diameter is required, which makes the printer apparatus complicated and expensive. There was a problem.

Japanese Patent Application Laid-Open No. 61-48274 discloses that
When the resolution ratio is a non-integer multiple, a technique is described that enlarges the apparent spot diameter, writes by changing the diameter with a dot, and enables easy change in resolution and printing. This complicates the configuration and is expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inexpensive electrophotographic printer capable of adjusting a resolution conversion rate even when a designated resolution and a resolution of a printer differ by a non-integer multiple. is there.

[0014]

According to the present invention, a reception control unit for receiving data from a host computer, a reception buffer for storing received data, a data analysis unit for analyzing received data, A drawing unit that generates bitmap data of an actual print format based on the data, an image buffer that stores the generated bitmap data, an output control unit that sends data in the image buffer to a printing mechanism unit, and a host. Resolution determining means for determining whether a logical resolution specified by a computer matches the physical resolution of the printing mechanism unit, and, when the logical resolution is different from the physical resolution, performing resolution conversion and printing out And a setting changing means for changing a setting of whether to perform print output without performing resolution conversion. Printer can be obtained.

Preferably, the setting change unit converts the resolution between the logical resolution and the physical resolution and prints out the output, and a non-converting output unit prints out the output without performing the resolution conversion. And means for selecting one of the conversion output means and the non-conversion output means.

Preferably, the conversion output means includes: a resolution conversion rate calculating means for calculating a resolution conversion rate based on the logical resolution and the physical resolution; and when the resolution conversion rate is an integer, the logical resolution is multiplied by an integer. Integer multiple conversion means for logically converting the data, non-integer multiple conversion means for logically converting the logical resolution by a non-integer multiple when the resolution conversion rate is a non-integer, and when the resolution conversion rate is a non-integer. An inner ring integer multiple conversion unit for logically converting the logical resolution by the maximum integral multiple of the inner ring; and a unit for selecting one of the non-integer multiple conversion unit and the inner ring integer multiple conversion unit. .

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

FIG. 1 is a block diagram of the control unit of the electrophotographic printer according to the present invention. The basic printing process is performed as follows. Data transmitted from the host computer 1 is input to the printer control unit 2. The data is transmitted to the reception control unit 4
And stores it in the reception buffer 9. Receive buffer 9
The data inside is read and analyzed by the data analysis unit 5. When the data analysis unit 5 recognizes various control codes,
Processing such as various mode settings is executed according to the control code. When the data analysis unit 5 recognizes print data such as characters, images, and figures, it performs editing processing such as calculation of a print position of the data and generation of print pattern data, and stores the generated data in the intermediate code buffer 10. . The data in the intermediate code buffer 10 is read and processed by the drawing unit 7. The drawing unit 7 generates bitmap data of an actual print format based on the data of the intermediate code, and stores the data in the image buffer 11. The image buffer 11 has a capacity to store one page of data. When one page of data is generated and printing is started, the output control unit 8 issues a print start request to the printing mechanism unit 3 and also outputs the data in the image buffer 11 to the VD.
The printing is performed by transferring one dot line at a time as O data.

Next, the logical resolution conversion processing will be described.

The physical resolution of the printer is fixed, and the printer control unit 2, especially the resolution conversion control unit 6, holds resolution information indicating the physical resolution as a fixed value. Also,
The logical resolution is attached to the print data, and is notified to the printer by a control code from the host computer.

Referring to the output signal from the data analyzer 5,
The resolution conversion control unit 6 determines the resolution conversion rate and generates print pattern data. If the conversion rate is an integer multiple,
Or, when the resolution integral multiple conversion function is set to invalid, the resolution conversion processing is performed at the same conversion rate, and when the conversion rate is a non-integer multiple and the resolution integral multiple conversion function is set to valid, , In the calculation of the conversion rate, round down the decimal point, set the maximum integer multiple logical conversion rate in the inner ring,
The resolution conversion processing is performed so that the print data matches the physical resolution of the printer at the conversion rate, and the generated print pattern data is stored in the intermediate code buffer 10. The validity / invalidity of the resolution multiple conversion function is set by a control code from a host computer or by information from a printer operation panel. The processing after storing the print pattern data in the intermediate code buffer 10 is the same as the conventional processing.

The above-described processing is normally executed by a software program using a microcomputer.

The operation of the resolution conversion control unit 6 will be described with reference to FIG. 2 together with FIG. The data received from the host computer 1 is stored in the reception buffer 9, analyzed by the data analysis unit 5, and passed to the resolution conversion control unit 6.
First, the resolution conversion control unit 6 determines whether the received data is a resolution integer multiple conversion function enable / disable control command (step 201). If the command is a resolution integer multiple conversion function valid / invalid control command, it is determined whether the command is valid or invalid (step 209). If it is specified to be valid, the resolution integer multiple function flag is turned on (step 210).
If invalid, the resolution integer multiple function flag is turned off (step 211). If the received data is not a resolution integer multiple conversion function enable / disable control command,
It is determined whether the command is a logical resolution designation command from the host computer 1 (step 202). If the command is a logical resolution designation command, the designated logical resolution information is stored in the memory of the printer control unit 2 (step 212). If the received data is not a logical resolution designation command, it is determined whether the received data is print data (step 20).
3). If it is not print data, the process exits the resolution conversion process without doing anything. If the data is print data, the logical resolution designated by the host computer is compared with the physical resolution of the printer, and it is determined whether or not the two match (step 204). When performing step 204,
The resolution conversion control section 6 functions as resolution determination means.

If the logical resolution matches the physical resolution of the printer, it is determined that resolution conversion is unnecessary and the conversion rate is set to 1
(Step 213). At this time, since the printout is performed without performing the resolution conversion, the resolution conversion control unit 6 is referred to as a non-conversion output unit.

If the resolutions do not match, the resolution conversion described below is performed. At this time, since the resolution conversion is performed and the printout is performed, the resolution conversion controller 6 is referred to as a non-conversion output unit. When changing the setting of whether or not to perform the resolution conversion, the resolution conversion control unit 6 functions as a setting change unit.

If the resolutions do not match, it is determined from the resolution integral multiple function flag whether the resolution integral multiple conversion function is valid or invalid (step 205). When executing Step 205, the resolution conversion control unit 6 functions as a conversion selection unit.

If the resolution integral function flag has been set to be valid, the resolution conversion rate is calculated by equation (1) (step 206).

[0028]

## EQU1 ## Resolution conversion rate = [physical resolution / logical resolution]
According to the equation (1), the logical conversion rate consisting of the largest integer multiple in the inner ring is calculated. Referring to the logical resolution conversion diagram of FIG. 3, for example, the resolution of the printer is 400 dpi (dot / dot).
Inches) and the resolution of the data from the host computer is 300 dpi (dots / inch), the resolution conversion rate is 400/300 = 1 (rounded down to the decimal point), and the original data (FIG. 3C) Printed as is.

If the resolution integral multiple function flag has been set to invalid, the resolution conversion rate is calculated by equation (2) (step 207).

[0030]

## EQU2 ## Resolution conversion rate = physical resolution / logical resolution According to equation 2, the resolution conversion rate is expressed as a fraction, and a non-integer multiple conversion rate is set. Referring to the logical resolution conversion diagram of FIG. 3, for example, if the resolution of the printer is 400 dpi (dots / inch) and the resolution of the data from the host computer is 300 dpi (dots / inch), the resolution conversion rate is 400 / (dot / inch). 300 = 4/3, and the data is printed in a pattern (FIG. 3B) obtained by multiplying the original data by 4/3.

After calculating the conversion rate, the print data is converted according to the conversion rate (step 208).

FIG. 4 shows an example of the print result of the present invention.
(A) shows the print result when the integer multiple logical conversion rate of the present invention is applied, and (B) shows the print result when converted at the non-integer multiple conversion rate. In FIG. 10A, the print size is small, but a high quality print result is obtained. In FIG. 10B, the print size is correct, but a low quality print result is obtained due to the disturbance of the print pattern.

[0033]

As described above, according to the present invention,
You can choose whether to give priority to print data quality or size.If quality is prioritized, all data including image data can be printed at the same high quality as the original data. Further, it is possible to prevent the print quality from deteriorating without adding a special control circuit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electrophotographic printer according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of a resolution conversion control unit included in the electrophotographic printer of FIG.

FIG. 3 is an explanatory diagram of logical resolution conversion.

FIG. 4 is an explanatory diagram of an example of a print result by the electrophotographic printer of FIG. 1;

FIG. 5 is a block diagram showing a configuration of a conventional electrophotographic printer.

FIG. 6 is an explanatory diagram of a configuration of a printing mechanism of the electrophotographic printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host computer 2 Printer control part 3 Printing mechanism part 4 Reception control part 5 Data analysis part 6 Resolution conversion control part 7 Drawing part 8 Output control part 9 Reception buffer 10 Intermediate code buffer 11 Image buffer

Claims (3)

[Claims] 1. A reception control unit for receiving data from a host computer, a reception buffer for storing received data, a data analysis unit for analyzing received data, and a bit of an actual print format based on the analyzed data. A drawing unit for generating map data; an image buffer for storing the generated bitmap data; an output control unit for sending data in the image buffer to a printing mechanism; A resolution determination unit that determines whether the logical resolution matches the physical resolution; and, if the logical resolution is different from the physical resolution, performs a resolution conversion to print out or prints out without performing the resolution conversion. And a setting change means for changing the setting. 2. The method according to claim 1, wherein the setting change unit performs a resolution conversion between the logical resolution and the physical resolution and outputs the printout, and a non-conversion output unit that prints out without performing the resolution conversion. 2. An electrophotographic printer according to claim 1, further comprising means for selecting one of said conversion output means and said non-conversion output means. 3. The conversion output unit includes: a resolution conversion ratio calculation unit that calculates a resolution conversion ratio based on the logical resolution and the physical resolution; and when the resolution conversion ratio is an integer, multiplies the logical resolution by an integer. Integer multiple conversion means for performing logical conversion, non-integer multiple conversion means for logically converting the logical resolution by a non-integer multiple when the resolution conversion rate is a non-integer, and the non-integer multiple conversion means when the resolution conversion rate is a non-integer. Inner ring integer multiple conversion means for logically converting the logical resolution by the maximum integral multiple of the inner ring;
3. An electrophotographic printer according to claim 2, further comprising means for selecting one of said non-integer multiple conversion means and said inner ring integer multiple conversion means.