JP2001287399A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily and accurately adjust a timing for starting the printing. SOLUTION: When a print position adjusting mode is set, a CPU 1 allows each of sections to operate to print an L-shape image. A shift amount of a top margin with respect to a designed value is calculated on the basis of a detection timing of a top end of a paper P by a discharge sensor 8 in a discharge process of the paper P having the L-shape image printed thereon and a detection timing of the L-shape image by a reflection sensor 9 and the timing for starting the printing in a sub-scanning direction is updated so as to compensate the shift amount. A shift amount of a left margin with respect to a designed value is calculated on the basis of a detection timing of the top of the paper P by the discharge sensor 8 in a process for conveying the paper P having the L-shape image printed thereon in a condition that the paper P is rotated 90 degrees and a detection timing of the L-shape image by the reflection sensor 9 and the timing for starting the printing in a main scanning direction is updated so as to compensate the shift amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, such as a laser printer, which prints an image by carrying out main scanning with a laser scanner or the like while carrying a document and performing sub-scanning.

[0002]

2. Description of the Related Art In a printing apparatus such as a laser printer, printing start timings in a sub-scanning direction and a main scanning direction are set so that an image is printed at a predetermined position on a sheet.

However, even in apparatuses manufactured under the same design, the printing start position on paper varies due to the variation in mechanical accuracy of each unit, and the top margin and the left margin differ.

Therefore, conventionally, in adjustment work before shipping,
After the operator prints the test chart, the top margin and the left margin are manually measured from the test chart. Then, based on the result of the measurement, the operator sets the print start timing in the sub-scanning direction and the main scanning direction so that the top margin and the left margin become specified values.

[0005]

Therefore, in the prior art, the adjustment work before shipment had to be performed entirely by hand, and the work was complicated, so that it was very troublesome. I was

Further, since the printing start timings in the sub-scanning direction and the main scanning direction are determined by the operator, there is a possibility that an erroneous setting may be made.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a printing apparatus that can easily and accurately adjust a print start timing.

[0008]

In order to achieve the above object, a first aspect of the present invention is to provide, for example, a paper feeding mechanism, a photosensitive drum, a fixing device, or a paper discharging device along a predetermined conveying path. While performing sub-scanning by being conveyed by conveying means including rollers, the main scanning unit including, for example, a photosensitive drum, a charging device, a laser scanner, a developing device, and a transfer roller performs the sub-scanning direction on the sheet. In a printing apparatus that prints an image by performing main scanning in an intersecting main scanning direction, at a predetermined position corresponding to a printing start position in the sub-scanning direction and a predetermined position corresponding to a printing start position in the main scanning direction. First and second
A mark print control means such as an L-shaped image print control means realized by software processing of a CPU, for example, which causes the main scanning means to print a predetermined mark image such as a black line, and the first and second mark images. Mark position detecting means for detecting a formation position of a mark image on the sheet; and the first position detected by the mark position detecting means.
The amount of deviation between the mark image formation position and the reference position of the first mark image, the formation position of the second mark image detected by the mark position detection means, and the reference position of the second mark image. Deviation calculation means for calculating the deviation amount of the sub-scanning deviation amount and the main scanning deviation amount, respectively,
Adjusting means realized by software processing of a CPU, for example, which adjusts the printing start timing in the sub-scanning direction according to the sub-scanning deviation amount, and adjusts the printing start timing in the main scanning direction according to the main scanning deviation amount. With.

By taking such means, printing on paper is actually performed, and the positions of the printed first and second mark images in the paper in the sub-scanning direction and the main scanning direction are determined. Is calculated, and the print start timing is adjusted so as to compensate for the shift amount. Therefore, the measurement of the print position deviation amount and the adjustment of the print start timing are automatically performed.

According to a second aspect of the present invention, in the first aspect, the deviation calculating means includes a sheet detecting means such as a discharge sensor for detecting that the sheet has reached a predetermined first position on the transport path. And a mark detection unit such as a reflection sensor for detecting the mark image at a predetermined second position on the transport path downstream of the first position with respect to the transport path. Means for immediately after the printing of the mark image is performed under the control of the mark printing control means, from when the paper is detected by the paper detecting means to when the mark image is detected by the mark detecting means. Calculating the sub-scanning deviation amount based on the elapsed time, for example, a sub-scanning deviation amount calculating unit realized by software processing of a CPU;
In response to an instruction to start detection of a main scanning deviation, after the transport unit starts transporting the paper set at a predetermined position, the paper is detected by the paper detection unit, and then the mark image is detected by the mark detection unit. The main scanning deviation amount is calculated based on the elapsed time until is detected, for example, C
And a main scanning deviation amount calculating means realized by software processing of the PU.

By taking such means, the amount of sub-scanning deviation and the amount of main-scanning deviation are calculated based on the output of a simple set of sensors for detecting the presence or absence of a sheet and the presence or absence of a mark.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a main configuration of a printing apparatus according to the present embodiment.

The printing apparatus of this embodiment is of an electrophotographic type, and has a CPU 1 and a ROM as shown in FIG.
2, RAM3, external interface unit (external IF unit)
4, an input / output processing unit 5, a smoothing processing unit 6, an operation panel 7, an ejection sensor 8, a reflection sensor 9, and an electrophotographic mechanism unit 10. And CPU1, ROM2, RAM
3, the external interface unit 4 and the input / output processing unit 5,
They are connected to each other via a system bus BUS.

The electrophotographic mechanism 10 further includes a photosensitive drum 11, a charger 12, a laser scanner 13, and a developing device 1.
4. Transfer roller 15, cleaning device 16, fixing device 17, paper feed mechanism 18, paper discharge roller 19, and motor 2.
Has zero.

The photosensitive drum 11 is formed of a conductor such as aluminum, for example, and has a photosensitive layer formed by coating a photosensitive conductive material on the outer peripheral surface. Photosensitive drum 11
Is rotated in the direction of the arrow shown in the figure by receiving the rotational force of the motor 20 by a driving force transmission mechanism (not shown). Around the photosensitive drum 11, a charger 12, a laser scanner 13, a developing device 14, a transfer roller 15, and a cleaning device 16 are arranged along the outer peripheral surface of the photosensitive drum 11.

The charger 12 is, for example, a well-known scorotron charger, and uniformly charges the surface of the photosensitive drum 11 to a predetermined potential.

The laser scanner 13 outputs a laser signal for turning on / off a laser diode in accordance with image data supplied from the smoothing processing unit 6 to the photosensitive drum 11.
Exposure is performed by scanning the photosensitive surface of the photosensitive drum 11 to form an electrostatic latent image on the photosensitive surface of the photosensitive drum 11.

The developing device 14 develops the electrostatic latent image formed on the photosensitive surface of the photosensitive drum 11 with toner, and forms a toner image on the photosensitive surface of the photosensitive drum 11.

The transfer roller 15 is applied with a transfer voltage of a predetermined voltage value having a polarity opposite to the charged potential of the toner from a transfer power supply (not shown). The transfer roller 15 transfers the toner image formed on the photosensitive drum 11 to the paper P supplied between the paper feed mechanism 18 and the photosensitive drum 11 (transfer position).

The cleaning device 16 scrapes off and collects the toner remaining on the photosensitive drum 11 without being transferred onto the sheet P.

The fixing device 17 melts and fixes the toner image transferred on the sheet P to the sheet P.

The paper feed mechanism 18 conveys the sheets set on the paper tray T one by one to a transfer position.

The paper discharge roller 19 discharges the paper P, on which the print image has been fixed by the fixing device 17, to the outside of the electrophotographic mechanism section 10.

The motor 20 includes one or a plurality of motors, and generates a rotating force for rotating various rotating bodies included in the electrophotographic mechanism unit 10.

The CPU 1 performs a process for controlling all the components of the printing apparatus based on an operation program stored in the ROM 2.

The ROM 2 stores an operation program for the CPU 1 and various data necessary for the CPU 1 to perform various processes.

The RAM 3 uses a DRAM or an SRAM, and temporarily stores data necessary for the CPU 1 to perform various processes.

The external interface unit 4 performs data transmission with an external device such as a personal computer, for example, for taking in image data.

The input / output processing unit 5 is configured using, for example, an ASIC. The input / output processing unit 5 includes a smoothing processing unit 6, an operation panel 7, a discharge sensor 8, and a reflection sensor 9.
And an interface process between the motor 20 and the system bus BUS.

The image data to be printed is given to the smoothing processing section 6 via the input / output processing section 5 under the control of the CPU 1. Then, the smoothing processing unit 6 performs a smoothing process on the image data for smoothing the edge of the image indicated by the image data, and outputs the image data to the laser scanner 13. Smoothing processing unit 6
In outputting image data to the laser scanner 13, a clock signal DO generated internally in synchronization with a beam detection signal BD generated by the laser scanner 13
TCLK is used. Then, the smoothing processing section 6 outputs the clock signal DOTCLK to the input / output processing section 5.

The operation panel 7 receives various instruction inputs from the operator to the CPU 1, and displays various information to be notified to the operator.

As the discharge sensor 8, for example, a transmission type optical sensor or the like is used. The discharge sensor 8 is provided downstream of the fixing device 17 in the transport path of the paper P,
The paper that has reached this position is detected.

The reflection sensor 9 uses a reflection type optical sensor. The reflection sensor 9 is provided at a predetermined distance from the discharge sensor 8 on the downstream side of the position where the discharge sensor 8 is provided in the transport path of the sheet P, and a black image is provided at a predetermined position of the sheet conveyed to this position. Is formed or not.

By the way, the processing means realized by the CPU 1 by software processing are, in addition to well-known general means in a printing apparatus, an L-shaped image printing control means, a sub-scanning deviation amount calculating means, a main scanning deviation amount calculating means, and an adjusting means. Means.

Here, the L-shaped image printing control means has a predetermined L for measuring a top margin and a left margin.
A control process for printing the character image in the electrophotographic mechanism unit 10 is performed.

The sub-scanning deviation amount calculating means measures the top margin based on the detection results of the discharge sensor 8 and the reflection sensor 9 when printing the L-shaped image under the control of the L-shaped image printing control means. Then, a shift amount of the print start timing in the sub-scanning direction (hereinafter, referred to as a sub-scan shift amount) is calculated based on this.

The main scanning shift amount calculating means conveys the sheet P on which the L-shaped image is re-set on the sheet tray T after printing of the L-shaped image and calculation of the sub-scanning shift amount. Let Then, the left margin is measured based on the detection results of the discharge sensor 8 and the reflection sensor 9 at this time, and based on this, the shift amount of the print start timing in the main scanning direction (hereinafter, referred to as the main scanning shift amount) is determined. calculate.

The adjusting means adjusts the sub-scanning deviation calculated by the sub-scanning deviation calculating means and the main scanning deviation calculated by the main scanning deviation calculating means in the sub-scanning direction and the main scanning direction. Adjust each print start timing.

Next, the operation of the printing apparatus configured as described above will be described.

When adjusting individual devices (units) before shipment, the operator designates the setting of the print position adjustment mode by a predetermined instruction operation on the operation panel 7.

When the setting of the print position adjustment mode is designated, the CPU 1 starts a print position adjustment process as shown in FIG.

In this print position adjusting process, the CPU 1 first starts the process of printing an L-shaped image (step ST).
1). This L-shaped image printing process is almost the same as the process for normal image printing, but the image to be printed is an L-shaped image as shown in FIG. L-shaped image is 2
This is an image in which black lines L1 and L2 are arranged in an L shape, and the image data is stored in, for example, the ROM 2.

The black line L1 is a line along the main scanning direction having a width of one to several lines including the first line in one page. Therefore, the width from the leading edge of the sheet P to the black line L1 corresponds to the top margin. The black line L2 is a line extending in the sub-scanning direction and having a width of one to several dots including the first dot in one page. Therefore, from the left end of the paper P, the black line L
The width up to 2 corresponds to the left margin.

Note that the printing start timing in the sub-scanning direction for printing an image is obtained by measuring the elapsed time from a predetermined timing related to the conveyance of the paper P by counting the beam detection signal BD, and setting this to a certain set value Ta. It becomes the time when it became. The printing start timing in the main scanning direction is the time when the elapsed time from the output of the beam detection signal BD is measured by counting the clock signal DOTCLK and reaches a certain set value Tb. The set value Ta and the set value Tb are to be set in a BD counter register and a DOTCLK counter register, and their design values are set at the time of manufacture.

Thus, if the electrophotographic mechanism 10 operates as designed, printing is performed using a fixed area of the paper P as an image printing area, and the top margin and the left margin are as designed. .

The paper P on which the L-shaped image has been printed in this way is discharged out of the electrophotographic mechanism 10 by the paper discharge roller 19, and in this process, the discharge sensor 8 and the reflection sensor 9 detect the paper P. Will pass through the position. At this time, when the leading edge of the sheet P passes the detection position of the ejection sensor 8, the ejection sensor 8 changes from OFF to ON, and the leading edge of the sheet P is detected. Subsequently, when the black line L1 passes through the detection position of the reflection sensor 9, the reflection sensor 9 is turned on.
From OFF to black line L1 is detected.

Therefore, the CPU 1 monitors the output states of the discharge sensor 8 and the reflection sensor 9 and measures the elapsed time Tm from when the discharge sensor 8 is turned on to when the reflection sensor 9 is turned off as shown in FIG. (Step ST2).

The elapsed time from when the discharge sensor 8 is turned on to when the reflection sensor 9 is turned off is proportional to the size of the top margin. Therefore, when the top margin is as designed, the discharge sensor 8 is turned on. The elapsed time T _s1 from when the reflection sensor 9 is turned off to when the reflection sensor 9 is turned off is constant. Difference in the elapsed time Tm for this reason the elapsed time T _s1 is, and of being proportional to the amount of deviation between the design value and the value measured from the L-image of the top margin, CPU 1 is the (T _s1
−Tm) is updated so that the set value Ta of the BD counter register can be compensated (step ST3).

The paper P on which the L-shaped image has been printed by the processing up to this point is discharged to the outside of the electrophotographic mechanism unit 10. The discharged paper P is printed with the black line L2. Paper tray T in such a direction that the side of
After that, pressing the start button provided on the operation panel 7 after the setting is defined as a work procedure of the operator.

Then, after updating the set value Ta of the BD counter register, the CPU 1 waits for the start key to be pressed (step ST4). Then, in response to the operator pressing the start button in accordance with the procedure described above, conveyance of the paper P is started (step ST
5).

As a result, one sheet of paper P is transported along the paper transport path for printing. This transported paper P has an L-shaped image already printed thereon, and The CPU 1 does not perform an operation for image formation. Accordingly, the sheet P is conveyed as it is along the conveyance path, and is eventually discharged by the discharge roller 19 to the electrophotographic mechanism 10.
Is discharged out of the device. In this process, the discharge sensor 8
And it passes through the detection position of the reflection sensor 9.
At this time, when the leading edge of the sheet P passes the detection position of the ejection sensor 8, the ejection sensor 8 changes from OFF to ON, and the leading edge of the sheet P is detected. Subsequently, when the black line L2 passes through the detection position of the reflection sensor 9, the reflection sensor 9 changes from ON to OFF, and the black line L2 is detected.

The CPU 1 monitors the output states of the discharge sensor 8 and the reflection sensor 9 and measures the elapsed time Tm from when the discharge sensor 8 is turned on to when the reflection sensor 9 is turned off, as shown in FIG. (Step ST6).

At this time, an L-shaped image is printed on the leading end of the paper P.
The discharge sensor 8 is turned on
The elapsed time from when the reflection sensor 9 turns off is
Is proportional to the size of the margin. And left merge
Discharge sensor 8 is turned on when
Elapsed time T from when the reflection sensor 9 is turned off _s2
Is constant. Therefore, the elapsed time T_s2Elapsed time for
Tm difference is the value measured from the L-shaped image of the left margin
CPU1 is proportional to the amount of deviation between
(T_s2−Tm) so that DOTCLK
Update the set value Tb of the data register (step ST
7).

When the updating of the set value Tb of the DOTCLK counter register is completed,
U1 ends the current print position adjustment processing.

As described above, according to this embodiment, the L-shaped image forming the black line L1 and the black line L2 is printed at the printing start position in the sub-scanning direction and the printing start position in the main scanning direction, respectively. The top margin is measured as the distance from the leading edge of P to the black line L1, and the left margin is measured as the distance from the left end of the paper P to the black line L2, and the sub-scanning direction is compensated for the deviation from these design values. In addition, the print start timing in the main scanning direction is automatically adjusted. Therefore, there is no need for the operator to measure the top margin and the left margin, and to set the print start timing in the sub-scanning direction and the main scanning direction, thereby greatly reducing the labor required for the adjustment work before shipping. It becomes possible. Further, since no artificial judgment is made regarding the setting of the print start timing, there is no possibility that an erroneous setting due to a human error occurs.

According to the present embodiment, the measurement of the top margin and the measurement of the left margin are performed in a time-division manner, and both the discharge sensor 8 and the reflection sensor 9 are used. This can be realized with a simple configuration as compared with a case where sensors for performing the operations are individually provided.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the discharge sensor 8
And the top margin and the left margin are measured based on the time difference between the detection timings of the reflection sensor 9. However, for example, an image sensor is used to perform surface reading, and the top margin and the left margin are measured by image processing. May be. In this way, the top margin and the left margin can be measured simultaneously, and the operation of "resetting the paper P on which the L-shaped image is printed and discharged to the paper tray T and pressing the start button" is performed. It is possible to further reduce the labor of the worker by omitting the work of the worker.

In the above embodiment, the L-shaped image is printed for measuring the top margin and the left margin. However, the black line L1 and the black line L2 do not have to be connected. It does not need to be an image. Further, an image including a mark of an arbitrary shape may be used instead of the black line.

In the above embodiment, the black line L1 includes the first line in one page. However, a black line separated by a predetermined line from the first line may be printed. Although the black line L2 includes the first dot in one page, a black line separated by a predetermined dot from the first dot may be printed.

In the above embodiment, the printing apparatus of the electrophotographic system is exemplified, but the present invention can be applied to a case where another system is used.

In addition, various modifications can be made without departing from the gist of the present invention.

[0063]

According to the first aspect of the present invention, the sub-scanning is performed by conveying the predetermined sheet along the predetermined conveying path by the conveying unit, and the main scanning unit performs the sub-scanning direction on the sheet. A printing apparatus that prints an image by performing main scanning in a main scanning direction intersecting with a predetermined position corresponding to a printing start position in the sub-scanning direction and a predetermined position corresponding to a printing start position in the main scanning direction Mark print control means for causing the main scanning means to print first and second predetermined mark images, mark position detection means for detecting formation positions of the first and second mark images on the paper, The amount of deviation between the formation position of the first mark image detected by the mark position detection means and the reference position of the first mark image, and the mark position detection means A shift calculating unit for calculating a shift amount between the detected formation position of the second mark image and a reference position of the second mark image as a sub-scan shift amount and a main-scan shift amount, respectively; Adjusting means for adjusting the printing start timing in the sub-scanning direction in accordance with the amount of printing and the printing start timing in the main scanning direction in accordance with the amount of main scanning shift. The adjustment of the start timing is automatically performed, and the printing apparatus can easily and accurately adjust the print start timing.

According to a second aspect of the present invention, in the first aspect, the deviation calculating means includes a sheet detecting means for detecting that the sheet has reached a predetermined first position on the conveying path; Mark detection means for detecting the mark image at a predetermined second position on the transport path downstream of the first position on the path, and the mark calculation control means Immediately after the printing of the mark image under the control of the above, the sub-scanning is performed based on the elapsed time from when the sheet is detected by the sheet detecting means to when the mark image is detected by the mark detecting means. A sub-scanning shift amount calculating means for calculating a shift amount; and, in response to an instruction to start detection of a main scanning shift, causing the conveying means to start conveying the sheet set at a predetermined position. Main scanning deviation amount calculating means for calculating the main scanning deviation amount based on an elapsed time from when the paper is detected by the paper detecting means to when the mark image is detected by the mark detecting means. Because
The sub-scanning deviation amount and the main-scanning deviation amount are calculated based on the outputs of a simple set of sensors for detecting the presence or absence of a sheet and the presence or absence of a mark, respectively, and can be realized with a simpler configuration.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a main part of a printing apparatus according to an embodiment of the invention.

FIG. 2 is a flowchart showing a processing procedure at the time of print position adjustment processing by a CPU 1 in FIG. 1;

FIG. 3 is a diagram illustrating a print example of an L-shaped image.

FIG. 4 is a timing chart showing a relationship between a change timing of a state of a discharge sensor 8 and a change timing of a reflection sensor 9 when a sheet P on which an L-shaped image is printed is conveyed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... CPU 2 ... ROM 3 ... RAM 4 ... External interface part (external IF part) 5 ... Input / output processing part 6 ... Smoothing processing part 7 ... Operation panel 8 ... Discharge sensor 9 ... Reflection sensor 10 ... Electrophotographic mechanism part 11 ... Photosensitive drum 12 Charger 13 Laser scanner 14 Developing device 15 Transfer roller 16 Cleaning device 17 Fixing device 18 Paper feed mechanism 19 Paper discharge roller 20 Motor

Claims (2)

[Claims] 1. While performing a sub-scan by conveying a predetermined sheet along a predetermined conveyance path by a conveying unit, the main scanning unit performs the sub-scanning on the sheet in a main scanning direction crossing the sub-scanning direction. In a printing apparatus for printing an image by performing main scanning, a first position and a second predetermined position correspond to a predetermined position corresponding to a printing start position in the sub-scanning direction and a predetermined position corresponding to a printing start position in the main scanning direction. Mark print control means for causing the main scanning means to print the mark image of each of the above, mark position detection means for detecting the formation position of the first and second mark images on the paper, and detection by the mark position detection means The amount of deviation between the formation position of the first mark image and the reference position of the first mark image and the mark position detected by the mark position detection means. A shift calculating means for calculating a shift amount between a formation position of the second mark image and a reference position of the second mark image as a sub-scan shift amount and a main-scan shift amount, respectively; A printing apparatus, comprising: adjusting means for adjusting the printing start timing in the scanning direction and the printing start timing in the main scanning direction according to the main scanning deviation amount. 2. The apparatus according to claim 1, wherein the shift calculating unit includes: a sheet detecting unit configured to detect that the sheet has reached a predetermined first position in the transport path; and a downstream of the transport path from the first position in the transport path. Mark detecting means for detecting the mark image at a predetermined second position on the side, and the shift calculating means, immediately after the mark image is printed under the control of the mark print controlling means, A sub-scanning shift amount calculating unit that calculates the sub-scanning shift amount based on an elapsed time from when the sheet is detected by the sheet detecting unit to when the mark image is detected by the mark detecting unit; In response to the detection start instruction, the mark is detected after the sheet is detected by the sheet detecting means after the conveying means starts conveying the sheet set at a predetermined position. Printing apparatus as claimed in claim 1, characterized in that it comprises a main scanning shift amount calculating means for calculating the main scanning shift amount based on the elapsed time until the mark image is detected by the stage.