JP2001130084A - Method and apparatus for processing image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent recording outputs from tilting. SOLUTION: A predetermined part of a recording medium is detected, and a tilt angle of the recording medium is calculated on the basis of the detected result. A data address is converted according to the tilt angle. Data with the address converted is transmitted to a recording head. In this case, since the tilt angle of the recording medium is calculated and the data address is converted according to the tilt angle, recording outputs are prevented from tilting. When precise recording is required, recording outputs can be prevented from tilting without correcting a skew of the recording medium by making the recording medium abut against a recording medium feed roller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and an image processing apparatus.

[0002]

2. Description of the Related Art Conventionally, in a recording apparatus, for example, a page printer, printing as recording is performed in accordance with data sent from a host apparatus. For this purpose, an image processing apparatus is provided, the image processing is performed by the image processing apparatus based on the data, and a printout as a recording output is performed.

FIG. 2 is a control block diagram of a conventional page printer.

In FIG. 1, reference numeral 11 denotes a host device, 12 denotes an I / O-I / F circuit of a page printer, and 13 denotes a printer control unit (CPU). When an operator creates a document, a graphic, or the like in the application of the host device 11, a print instruction and an interrupt request are sent from the host device 11 to the page printer via the I / O-I / F circuit 12. Upon receiving the print instruction and the interrupt request, the printer control unit 13 receives a command for designating a paper size (not shown), a print resolution, a type of a paper feed tray (not shown), and image data, print data, and the like. A reception process for receiving data is started, and I / O-I
A predetermined status is sent via the / F circuit 12.

On the other hand, the host device 11 grasps the state of the page printer in accordance with the status sent from the printer control unit 13 and confirms that the printing process is possible. Send data.

Subsequently, upon receiving the command and the data, the printer control unit 13 starts a printing process in accordance with the steps of the program stored in the program ROM 14. Then, the printer control unit 13 analyzes the command and data to perform an editing process, and develops bitmap data composed of dot-based image data in a buffer memory, for example, the DRAM 15. In the development using the band buffer method, the DRAM 15
When the amount of bitmap data corresponding to the set area is expanded, and in the expansion by the full page buffer method, when the amount of bitmap data of one page is expanded, the printer controller 13 Sends an instruction to the heater drive circuit 20 to turn on the heater 21 of the fixing device (not shown), thereby heating the heat roller of the fixing device. When the temperature of the heat roller is detected by the thermistor 19, the printer control unit 13 sends an instruction to the fixing temperature control circuit 18 to read the temperature, and turns on / off the heater 21 based on the temperature. . Thus, the temperature of the heat roller is controlled.

The printer control unit 13 sends an instruction to a motor drive circuit 24 to drive a motor 25 such as a drum motor and a registration motor to feed out the printing paper from a paper feed tray to feed the printing paper. Starts transporting.
Further, the printer control unit 13 sends an instruction to the power supply control circuit 26 to operate the high-voltage power supply circuit 28, and the high-voltage power supply circuit 28 generates a high-voltage output of a process system such as charging, development, and transfer. And the printer control unit 13
Sends an instruction to the sensor detection circuit 22 and, when the printing paper is detected by the paper sensor among the sensors 23, controls the on / off sequence of the high voltage output in synchronization with the detection timing. Reference numeral 27 denotes a low-voltage power supply circuit that generates a low-voltage output of a control system.

Subsequently, when the printing paper is conveyed on a paper conveyance path in the page printer and comes into contact with a photosensitive drum (not shown), the printer control unit 13 sends an instruction to the head drive circuit 16 to send an instruction to the head driving circuit 16. The video data is transferred to the LED head 17 so that the print area matches the position of the electrostatic latent image on the photosensitive drum. The timing of the start of the paper feeding is synchronized with the detection of the front end of the printing paper by the paper sensor.

The video data transferred to the LED head 17 is composed of image data in dot units for one line of the width of one page of the printing paper, and includes video data corresponding to the head area coordinates in the printing area of the printing paper. Transfer starts.

In the case of performing monochrome printing, in the black portion, the light of the LED head 17 is irradiated on the photosensitive drum in accordance with the video data, and the surface potential of the photosensitive drum is lowered, so that the photosensitive drum is statically charged. While the latent image is written, in the white portion, the LED head 1
7 is not irradiated, and the surface potential of the photosensitive drum is not changed. Subsequently, toner is attached to the electrostatic latent image to form a toner image.

In this manner, image processing is performed, printing paper is fed and conveyed, and a series of printing processing is performed.

[0012]

However, in the above-described conventional page printer, if the printing paper set in a paper feed tray or the like is shifted or the accuracy of the printer mechanism is low, the printing paper skews. Since the paper is fed and transported as it is, the print output is inclined.

Normally, skew is corrected by starting the conveyance after the printing paper is once applied to the paper feed roller (once), but when precise printing is required, Even if the conveyance is started after the printing paper is applied to the paper feed roller, the skew cannot be corrected. Therefore, the print output is inclined.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing method and an image processing apparatus which can solve the problems of the conventional page printer and can prevent a print output from being tilted.

[0015]

For this purpose, in an image processing method according to the present invention, a predetermined portion of a recording medium is detected, a tilt angle of the recording medium is calculated based on the detection result, and the tilt angle corresponding to the tilt angle is calculated. Then, the address of the data is converted, and the converted data is transferred to the recording head.

In another image processing method according to the present invention, a predetermined portion of a recording medium is detected, an inclination angle of the recording medium is calculated based on the detection result, and the recording head is rotated in accordance with the inclination angle. Let it.

In the image processing apparatus of the present invention, a detecting means for detecting a predetermined portion of the recording medium, a calculating means for calculating an inclination angle of the recording medium based on a detection result by the detecting means, It has an address conversion means for converting the address of the data in correspondence therewith, and a transfer means for transferring the data whose address has been converted to the recording head.

According to another aspect of the present invention, there is provided an image processing apparatus comprising: detecting means for detecting a predetermined portion of a recording medium; calculating means for calculating a tilt angle of the recording medium based on a detection result by the detecting means; Recording head rotating means for rotating the recording head in accordance with the angle.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a transport system of a page printer according to a first embodiment of the present invention, and FIG.
FIG. 4 is a control block diagram of a page printer according to the embodiment.

In FIG. 3, reference numeral 11 denotes a host device, 12 denotes an I / O-I / F circuit of a page printer as a recording device,
13, a printer control unit (CPU); and 42, an address conversion circuit. When the operator creates a document, a graphic, or the like in the application of the host device 11, the host device 1
1 sends a print instruction as a recording instruction and an interrupt request to the page printer via the I / O-I / F circuit 12. When the printer control unit 13 receives the print instruction and the interrupt request, the printer control unit 13 specifies a paper size of a print paper as a recording medium (not shown), a print resolution, a type of a paper feed tray (not shown), and image data. Start reception processing for receiving data such as print data,
A predetermined status is sent to the host device 11 via the I / O-I / F circuit 12.

On the other hand, the host device 11 grasps the status of the page printer according to the status sent from the printer control unit 13 and confirms that the printing process as a recording process is possible. To send the command and the data.

Subsequently, upon receiving the command and the data, the printer control section 13 starts a printing process as a recording process in accordance with the steps of the program stored in the program ROM 14. Then, the printer control unit 1
Numeral 3 analyzes the command and data to perform editing processing, and develops bitmap data composed of image data in dot units in a buffer memory, for example, the DRAM 15. Also, in the development by the band buffer method, when the amount of bitmap data corresponding to the set area in the DRAM 15 is expanded, in the expansion by the full page buffer method, the amount of bitmap data of one page is increased. Is expanded, the printer control unit 1
An instruction is sent from 3 to the heater drive circuit 20, and the heater 21 of the fixing device (not shown) is turned on to heat the heat roller of the fixing device. When the temperature of the heat roller is detected by the thermistor 19, the printer control unit 13 sends an instruction to the fixing temperature control circuit 18 to read the temperature, and turns on / off the heater 21 based on the temperature. . Thus, the temperature of the heat roller is controlled.

The printer control unit 13 sends an instruction to a motor drive circuit 24 to drive a motor 25 such as a drum motor and a registration motor to feed out the printing paper from a paper feed tray to feed the printing paper. Starts transporting.
Further, the printer control unit 13 sends an instruction to the power supply control circuit 26 to operate the high-voltage power supply circuit 28, and the high-voltage power supply circuit 28 generates a high-voltage output of a process system such as charging, development, and transfer. And the printer control unit 13
Sends an instruction to the sensor detection circuit 41 so that the printing paper is detected by the first to third paper sensors 32, 33, 35 as detection means.
, The on / off sequence of the high voltage output is controlled in synchronization with the detection timing. Reference numeral 27 denotes a low-voltage power supply circuit for generating a low-voltage output of the control system, and reference numeral 30 denotes other sensors. In addition, the first to third
Paper sensors 32, 33, and 35 detect a predetermined portion of the printing paper, for example, a front end.

Subsequently, when the printing paper is conveyed on the paper conveyance path in the page printer and comes into contact with a photosensitive drum (not shown), the printer control unit 13 issues an instruction to the video I / F circuit 43 as a transfer means. The video data is transferred to the LED head 17 as a recording head so that the printing area on the printing paper coincides with the position of the electrostatic latent image on the photosensitive drum. Note that the timing of the start of the paper feeding is synchronized with the detection of the front end of the printing paper by the first to third paper sensors 32, 33, and 35.

The video data transferred to the LED head 17 is composed of image data in dot units for one line of the width of one page of the printing paper, and from video data corresponding to the head area coordinates in the printing area of the printing paper. Transfer starts.

When printing a single color as a record, the black portion is determined according to the video data.
The light of the LED head 17 is irradiated on the photoconductor drum, and the surface potential of the photoconductor drum is lowered to write an electrostatic latent image.
Is not irradiated, and the surface potential of the photosensitive drum is not changed. Subsequently, toner is attached to the electrostatic latent image to form a toner image.

As described above, image processing is performed, printing paper is fed and conveyed, and a series of printing processing is performed.

Next, the transport system of the page printer will be described.

In FIG. 1, reference numeral 31 denotes a paper feed roller as a recording medium supply roller, and reference numeral 34 denotes a conveyance roller. By rotating the paper supply roller 31 and the conveyance roller 34, a printing paper (not shown) Paper is fed in the direction of arrow A1 from a tray or a manual paper feed port, and is transported on a paper transport path. At this time, the front end of the printing paper reaches the first and second paper sensors 32 and 33, and the first and second paper sensors 32 and 33 reach the first and second paper sensors.
When the lever (not shown) is tilted and the phototransistor (not shown) is switched in the paper sensors 32 and 33, the passage timing of the printing paper is detected. 41, the signal is processed by the printer controller 13
Sent to

A third paper sensor 35 for adjusting the timing of writing by the LED head 17, the timing of high-voltage output for each process, and the like is disposed downstream of the transport roller 34 in the paper transport path. Is done. When the front ends of the printing paper are detected by the first to third paper sensors 32, 33, and 35, and the necessary timing adjustments are completed, the printing paper is transferred to the gap (the gap between the drum cartridge 37 and the transfer roller 36). And the toner image on the photosensitive drum is transferred, and then the printing paper on which the toner image has been transferred is sent to a fixing device, where it is heated and fixed by the heat roller 38 of the fixing device. .
Reference numeral 39 denotes a discharge sensor for detecting that the print paper has been discharged, and reference numeral 40 denotes a discharge roller for discharging the print paper.

Next, the operation of the page printer configured as described above will be described.

FIG. 4 is an explanatory view showing a state in which the printing paper is skewed in the first embodiment of the present invention, and FIG. 5 is a view showing the first embodiment of the present invention.
9 is a time chart of output signals of first and second paper sensors according to the embodiment.

In FIG. 4, P1 comprises points A to D,
A rectangle P2 representing the printing paper conveyed in the direction of the arrow A1 in a normal state is composed of points A 'to D', and when it is detected that the paper is skewed, that is, the front end of the printing paper is the A square P3 representing the printing paper at the time when the sheet sensor 32 reaches the first paper sensor 32 is composed of points A "to D", and the square P1 is rotated counterclockwise around the point C by an inclination angle α to obtain the square. It is a square placed in a positional relationship parallel to P2. The inclination angle α represents a skew angle.

Here, the point C is defined as the origin, the coordinates of an arbitrary point p on the square P1 are defined as p (x, y), and the square P2
The coordinates of a point p 'corresponding to the point p above are p'
When (x ', y') is set, coordinates p '(x', y ') are calculated based on the coordinates p (x, y). Note that x
The coordinates, y coordinates, x 'coordinates, and y' coordinates all take negative values.

When the printing paper is skewed and conveyed in the state shown by the square P2 in FIG. 4, the timing at which the output signal of the first paper sensor 32 changes from the high level to the low level is determined by the timing shown in FIG. Time t from the timing when the output signal of the second paper sensor 33 changes from the high level to the low level.
Only slow. Then, assuming that the feeding speed of the printing paper is sp and the distance between the first paper sensor 32 and the second paper sensor 33 is L, the inclination angle α is α = tan ⁻¹ (sp · t / L) (1)

The coordinates of the point C are represented by C (0,0), the coordinates of the point p ″ on the square P3 corresponding to the point p are represented by p ″ (x ″, y ″), and the points p, Assuming that the angle formed by the straight line connecting C and the straight line connecting points B and C is θ, the angle θ is θ = cos ^-1 {x / {(x ² + y ² )}. Therefore, the x ″ and y ″ coordinates are x ″ = − ＝ (x ² + y ² ) · cos (θ−α) y ″ = − ＝ (x ² + y ² ) · sin (θ−α)

When the front end of the skewed printing paper reaches the second paper sensor 33, the x 'coordinate of the point p' is considered to be located in the middle between the points p and p ". Therefore, since the x coordinate of the point p is x = −√ (x ² + y ² ) · cos θ, the x ′ coordinate is x ′ = − (１ ／) · √ (x ² + y ² ) · ｛Cos (θ−α) + cosθ｝ (2) and the y ′ coordinate is y ′ = | − (1/2) · √ (x ² + y ² ) · ｛cos θ−cos (θ− α)｝ · tanα | (3)

Next, a description will be given of an image processing method for correcting a print output as a record output when a print sheet is conveyed obliquely.

FIG. 6 is a control block diagram of a main part of the page printer according to the first embodiment of the present invention. FIG. 7 is a diagram showing mask data in an address conversion circuit according to the first embodiment of the present invention. FIG. 8 is a diagram showing a state of address conversion according to the first embodiment of the present invention, FIG. 9 is a functional block diagram of a printer control unit according to the first embodiment of the present invention, and FIG. FIG. 11 is a flow chart showing the operation of the page printer according to the first embodiment of the present invention.

In FIG. 6, reference numeral 13 denotes a printer control unit (C
PU), 15 is a DRAM, 42 is an address conversion circuit for converting an address by coordinate conversion, 43 is a video I / F circuit, 46 is an address bus, and 47 is a data bus.

The printing paper (not shown) is skewed and conveyed, and when the front end of the printing paper reaches the first and second paper sensors 32 (FIG. 4) and 33, the printing paper is tilted to the left or right. When inclined by the angle α, the time t (FIG. 5) can be calculated from the difference between the timings at which the first and second sheet sensors 32 and 33 detect the front end of the printing sheet. Therefore, when the power of the page printer is turned on or when the printing paper is detected by the discharge sensor 39 (FIG. 1), a counter (not shown) in the sensor detection circuit 41 (FIG. 3) is cleared to zero. The counter starts counting when one of the first and second paper sensors 32 and 33, for example, the output signal of the second paper sensor 33 changes from a high level to a low level. For example, the counting ends at the timing when the output signal of the first paper sensor 32 changes from the high level to the low level, and the count value is written to a register (not shown) in the printer control unit 13 as the time t.

Next, a calculating means (not shown) in the printer control unit 13 calculates the inclination angle α by the equation (1) based on the time t. The printer control unit 13
Are enable / disable control signals a, RAS / C
The address conversion circuit 42, the DRAM 15, and the video I / F circuit 43 are accessed according to the AS control signal b and the read / write control signal c.

As shown in FIG. 7, the address conversion circuit 42 stores dot coordinate data representing the position where printing as the original recording should be performed, the paper size, the inclination angle α, and the position after the conversion. The transformation coordinate data to be represented is stored in association with each other as mask data. Note that the X coordinate and the Y coordinate of the dot coordinate data are the x coordinate of the point p in FIG.
The X coordinate and the Y coordinate of the transformed coordinate data correspond to the x 'coordinate and the y' coordinate of the point p ', respectively.

Therefore, the printer control unit 13
A command indicating the calculated inclination angle α, the paper size of the printing paper to be used, and the like are written in the register of the address conversion circuit 42, and, for example, the command and the X coordinate of the dot coordinate data as shown in FIG. An address conversion circuit 4 converts the data 1 consisting of the X coordinate address to be stored and the Y coordinate address at which the Y coordinate of the dot coordinate data is stored.
2, the address is converted in the address conversion circuit 42, and is composed of a reply, a converted X coordinate address in which the X coordinate of the converted coordinate data is stored, and a converted Y coordinate address in which the Y coordinate of the converted coordinate data is stored. It becomes data 2.

Next, the function of the printer control unit 13 will be described.

In FIG. 9, reference numeral 51 denotes a reception buffer;
Denotes an editing unit as editing means, 56 denotes a page buffer, 5
7, a memory management unit; 58, a developing unit as a developing means; 60, a raster buffer;
1. The page buffer 56 and the raster buffer 60 are DR
The editing unit 52 and the memory management unit 5 in the AM 15
7 and the developing unit 58 are provided in the printer control unit 13.

The data in the receiving buffer 51 is sent to an editing unit 52, in which a command of the data is decoded by an emulation module 53, and a printing of the data is printed by an editing core module 54. The data is edited, a display list is created, and the display list is stored in the page buffer 56.

Then, the data development processing section 59 in the development section 58 reads the display list from the page buffer 56 and develops the display list as image data in the raster buffer 60. The image data developed in the raster buffer 60 in this manner is sent to the LED head 17 via the video I / F circuit 43 as video data.

Here, when address conversion is necessary, an address conversion module 55 as address conversion means is used.
Converts addresses in dot units with the address conversion circuit 42. At this time, the data amount increases as the addresses are converted, so that the memory management unit 57 enlarges the working memory area of the page buffer 56.

By the way, as shown in FIG. 10, the display list is composed of addresses, print data, fonts, graphics, characters, and the like. 60 is developed as shown in FIG. Further, in the state after the correction, the image is developed in the raster buffer 60 as shown in FIG. Note that the display list in the state after the correction is composed of bitmap data.

Next, the operation of the page printer having the above configuration will be described.

When a print instruction is sent from the host device 11 to the page printer, the motor drive circuit 24 drives the motor 25 to feed printing paper. Next, the printer control unit 13
When the first and second paper sensors 32 and 33 detect the leading edge of the printing paper, the timings T1 and T2 at which the output signals of the first and second paper sensors 32 and 33 change from high level to low level are equal. Determine whether or not.

When the timings T1 and T2 are not equal, the printer control unit 13 calculates the time t, and the calculating means calculates the inclination angle α based on the time t, and calculates the inclination angle α together with the paper size of the printing paper. Write to the address conversion circuit 42. Next, the editing core module 54 performs an editing process of the print data and creates a display list. Further, the address conversion module 55 is configured to calculate the inclination angle α.
Is determined to be within a pre-registered allowable range, and if it is outside the allowable range, it is determined that address conversion is necessary. Then, the memory management unit 57 enlarges the working memory area of the page buffer 56 and corrects the display list.
The display list corrected in this way is developed as image data in the raster buffer 60 by the data development processor 59.

Next, the flowchart will be described. Step S1 A print instruction is received. Step S2 Print paper is fed. Step S3: Wait until the front end of the printing paper is detected. Step S4: It is determined whether the timings T1 and T2 are equal. If the timings T1 and T2 are equal, the process proceeds to step S6; otherwise, the process proceeds to step S5. Step S5: The inclination angle α is calculated, and the address conversion circuit 4
Write to 2. Step S6 Edit the print data. Step S7 Create a display list. Step S8: It is determined whether or not address conversion is necessary. If the address conversion is necessary, the process proceeds to step S9, and if not, the process proceeds to step S11. Step S9: Enlarge the working memory area. Step S10: The display list is corrected. Step S11 The image data is developed.

As described above, in the present embodiment, the printing paper set in the paper feed tray or the like is shifted or the accuracy of the printer mechanism is low, so that the printing paper is fed while being skewed. , The tilt angle α is calculated, and the display list can be corrected based on the tilt angle α. Therefore, it is possible to prevent the print output from tilting.

When precise printing is required,
It is possible to prevent the print output from being skewed without correcting the skew by applying the printing paper to the paper feed roller 31.

Next, a second embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

FIG. 12 is a control block diagram of a main part of a page printer according to the second embodiment of the present invention, FIG. 13 is a functional block diagram of a printer control unit according to the second embodiment of the present invention, and FIG. 9 is a flowchart illustrating an operation of the page printer according to the second embodiment of the present invention.

In this case, usually, the data development processing section 59
The image data expanded in the raster buffer 60 is read from the raster buffer 60 and transferred to the LED head 17 as a recording head via a video I / F circuit 43 as a transfer unit. When it is detected that the printing paper is skewed, the data is transferred to the address conversion circuit 65 via the data bus 48.

When the image data is transferred, the address conversion circuit 65 performs a bit operation on the image data based on the previously written inclination angle α and the paper size of the printing paper, and corrects the image data by shifting it. Then, the corrected image data is written into a built-in buffer (not shown). In this way, when a certain amount of image data is written to the buffer,
Image data is read out from the buffer and directly
The data is transferred to the head 17.

Next, the function of the printer control unit 13 will be described.

In FIG. 13, reference numeral 51 denotes a reception buffer;
6 is an editing unit as editing means, 56 is a page buffer,
57 is a memory management unit, 58 is a development unit as expansion means, 60 is a raster buffer, 67 is an address conversion unit as address conversion means, and the reception buffer 51, page buffer 56 and raster buffer 60 are stored in the DRAM 15, The editing unit 66, the memory management unit 57, and the development unit 58 are provided in the printer control unit 13, and the address conversion unit 67 is provided in the address conversion circuit 65.

The data in the reception buffer 51 is sent to an editing unit 66, in which a command of the data is decoded by the emulation module 53, and a print data of the data is decoded by the editing core module 54. Is performed, a display list is created, and the display list is stored in the page buffer 56.

Then, the data development processing section 59 in the development section 58 reads the display list from the page buffer 56 and develops the display list into the raster buffer 60 as image data.

Here, if address conversion is necessary, L
Immediately before the image data is transferred to the ED head 17 as video data, the address conversion unit 67 sets the inclination angle α set in the address conversion circuit 65 (FIG. 4).
And converts the address in dot units based on the paper size of the printing paper. For this purpose, mask data as shown in FIG. 7 is stored in the address conversion unit 67 in advance.

The image data whose addresses have been converted in this manner is sequentially written into a buffer (not shown) in the address conversion unit 67, and when a certain amount of image data is stored, the image data is converted to video data by an LED. The data is transferred to the head 17.

Next, the operation of the page printer having the above configuration will be described.

When a print instruction as a recording instruction is sent from the host device 11 to the page printer, the motor drive circuit 24
(FIG. 3) drives the motor 25 to feed the printing paper.
Next, the printer control unit 13 performs the first,
When the second paper sensors 32, 33 detect the leading edge of the printing paper, the timings T1, T2 at which the output signals of the first and second paper sensors 32, 33 change from high level to low level.
Judge whether are equal.

If the timings T1 and T2 are not equal, the printer control unit 13 calculates the time t (FIG. 5), and a calculation unit (not shown) in the printer control unit 13 calculates
The inclination angle α is calculated based on the time t, and is written into the address conversion unit 67 in the address conversion circuit 42 together with the paper size of the printing paper. Next, edit core module 5
Reference numeral 4 performs a print data editing process to create a display list. The display list created in this manner is developed by the data development processing unit 59 as image data in the raster buffer 60.

The address conversion unit 67
It is determined whether or not the inclination angle α falls within a pre-registered allowable range. If the tilt angle α exceeds the allowable range, it is determined that address conversion is necessary. And
The address conversion unit 67 includes a raster buffer 60.
, And converts the address of the image data. The image data whose address has been converted in this manner is stored as processed image data in a buffer in the address conversion unit 67, and the processed image data is read from the buffer at regular intervals and transferred to the LED head 17. Is done.

Next, the flowchart will be described. Step S21: A print instruction is received. Step S22: The printing paper is fed. Step S23: Wait until the front end of the printing paper is detected. Step S24: It is determined whether the timings T1 and T2 are equal. If the timings T1 and T2 are equal, the process proceeds to step S26; otherwise, the process proceeds to step S25. Step S25: The inclination angle α is calculated and written to the address conversion unit 67. Step S26 Edit the print data. Step S27: Expand the image data. Step S28: To judge whether the address conversion is necessary. If the address conversion is necessary, the process proceeds to step S29, and if not, the process ends. Step S29 The address is converted.

As described above, in the present embodiment, the address of the image data expanded in the raster buffer 60 is converted, and the address of the display list is not converted. Therefore, there is no need to enlarge the working memory area of the page buffer 56, so that the memory capacity can be reduced and the cost of the page printer can be reduced.

Next, a third embodiment of the present invention will be described.

FIG. 15 is a perspective view of a page printer according to the third embodiment of the present invention, and FIG. 16 is a flowchart showing the operation of the page printer according to the third embodiment of the present invention.

In the figure, reference numeral 70 denotes a main body of the page printer. When the stacker cover 72 of the main body 70 is opened, a drum cartridge 37 and a fixing unit 73 disposed on a paper transport path (not shown) are exposed. ing. On the back of the stacker cover 72, an LED head 17 as a recording head is provided so as to be swingable in the direction of the arrow. Also, a pulse motor 71 is provided, and the LED head 17 is driven by driving the pulse motor 71.
Can be rotated and placed in a predetermined rotation position.

Printing paper as a recording medium (not shown) is fed and transported on a paper transport path, and first and second paper sensors 32 (FIG. 4) and 33 as detecting means.
When the front end is detected and the skew of the printing paper is detected, the recording head rotating means (not shown) in the printer control unit 13 (FIG. 3) operates the pulse motor 71.
, The pulse motor 71 is driven very slightly, the main scanning direction of the LED head 17 is rotated, and the inclination angle α of the printing paper coincides with the angle in the main scanning direction. Therefore, it is possible to prevent the print output as the record output from being inclined.

Next, the operation of the page printer having the above configuration will be described.

When a print instruction as a recording instruction is sent from the host device 11 to the page printer, the motor drive circuit 24
Drives the motor 25 to feed printing paper. Next, the printer control unit 13 controls the first and second paper sensors 3.
It is determined whether or not the timings T1 and T2 at which the output signals 2 and 33 are changed from high level to low level are equal. If the timings T1 and T2 are not equal, a time t (FIG. 5) is calculated. The calculation means (not shown) calculates the inclination angle α based on the time t, and writes it into a pulse setting register (not shown) in the motor drive circuit 24. Then, the editing core module 54 (FIG. 13)
The print data is edited and a display list is created. Next, the data development processing unit 59 reads the display list from the page buffer 56, and uses the display list as image data in the raster buffer 60.
Expand to The image data expanded in the raster buffer 60 in this way is sent as video data to the video I / F circuit 43 as transfer means.

The address conversion unit 67 determines whether the inclination angle α falls within a pre-registered allowable range. If the inclination angle α exceeds the allowable range, the address conversion unit 67 writes the inclination angle α written in the pulse setting register. The pulse motor 71 generates a number of pulses corresponding to the angle α, drives the pulse motor 71 very slightly, and rotates the LED head 17 in the main scanning direction.

In this case, a bit shift is required for each line, but the video I / F circuit 43 performs the bit shift.

Next, the flowchart will be described. Step S31: A print instruction is received. Step S32: The printing paper is fed. Step S33: Wait until the front end of the printing paper is detected. Step S34: It is determined whether the timings T1 and T2 are equal. If the timings T1 and T2 are equal, the process proceeds to step S36; otherwise, the process proceeds to step S35. Step S35: The inclination angle α is calculated and written to the pulse setting register. Step S36 The print data is edited. Step S37: Expand the image data. Step S38: The main scanning direction of the LED head 17 is rotated. Step S39: The video data is transferred.

As described above, a bit shift is required for each line, but since it is not necessary to convert addresses in dot units, the processing time can be shortened.

In each of the above embodiments, the host device 1
Although a page printer that performs printing as a record of print data sent from the printer 1 has been described, the present invention is applied to a case in which image data obtained by reading an image by a scanner is printed. Can also.

The present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0086]

As described above in detail, according to the present invention, in the image processing method, a predetermined portion of the recording medium is detected, and the inclination angle of the recording medium is calculated based on the detection result. Convert the address of the data according to the tilt angle,
The data with the converted address is transferred to the recording head.

In this case, the inclination angle of the recording medium is calculated,
Since the address of the data is converted in accordance with the inclination angle, the inclination of the recording output can be prevented.

Then, when precise recording is required,
It is possible to prevent the recording output from being inclined without correcting the skew by applying the recording medium to the recording medium supply roller.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a transport system of a page printer according to a first embodiment of the present invention.

FIG. 2 is a control block diagram of a conventional page printer.

FIG. 3 is a control block diagram of the page printer according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating a state in which the printing paper is skewed in the first embodiment of the present invention.

FIG. 5 shows the first and second embodiments in the first embodiment of the present invention.
6 is a time chart of an output signal of the paper sensor of FIG.

FIG. 6 is a main part control block diagram of the page printer according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating mask data in an address conversion circuit according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a state of address conversion according to the first embodiment of the present invention.

FIG. 9 is a functional block diagram of a printer control unit according to the first embodiment of the present invention.

FIG. 10 is a diagram showing a conversion state of a display list in the first embodiment of the present invention.

FIG. 11 is a flowchart illustrating an operation of the page printer according to the first embodiment of the present invention.

FIG. 12 is a main part control block diagram of a page printer according to a second embodiment of the present invention.

FIG. 13 is a functional block diagram of a printer control unit according to the second embodiment of the present invention.

FIG. 14 is a flowchart illustrating an operation of the page printer according to the second embodiment of the present invention.

FIG. 15 is a perspective view of a page printer according to a third embodiment of the present invention.

FIG. 16 is a flowchart illustrating an operation of the page printer according to the third embodiment of the present invention.

[Explanation of symbols]

 13 Printer control unit 17 LED head 32, 33, 35 First to third paper sensors 43 Video I / F circuit 52, 66 Editing unit 55 Address conversion module 58 Expansion unit 67 Address conversion unit α Tilt angle

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C087 AB05 AC08 BA02 BA03 BC01 BD05 BD24 2H027 DA38 DC03 DC11 DE02 DE07 ED06 EE04 EE06 EF09 FD08 ZA07 5C051 AA02 CA08 DA03 DB02 DB11 DB29 DE09 DE12

Claims (6)

[Claims] (1) detecting a predetermined portion of a recording medium,
(B) calculating the tilt angle of the recording medium based on the detection result;
(C) converting the address of the data in accordance with the tilt angle; and (d) transferring the data with the converted address to the recording head. 2. (a) detecting a predetermined portion of a recording medium,
(B) calculating the tilt angle of the recording medium based on the detection result;
(C) an image processing method characterized by rotating the recording head in accordance with the inclination angle. (A) detecting means for detecting a predetermined portion of the recording medium; (b) calculating means for calculating an inclination angle of the recording medium based on a detection result by the detecting means; An image processing apparatus comprising: address conversion means for converting an address of data corresponding to a corner; and (d) transfer means for transferring data whose address has been converted to a recording head. 4. The image processing apparatus according to claim 3, wherein the address conversion unit converts an address of a display list formed based on editing of data by an editing unit. 5. The image processing apparatus according to claim 3, wherein the address conversion unit converts an address of the image data expanded by the expansion unit. 6. A detecting means for detecting a predetermined portion of the recording medium, a calculating means for calculating an inclination angle of the recording medium based on a detection result by the detecting means, and An image processing apparatus comprising: a recording head rotating unit configured to rotate a recording head in accordance with a corner.