JPH0550660A - Multiple color recorder - Google Patents

Abstract

PURPOSE:To provide a multiple color recorder which can prevent unnecessary correction for color shift by a method wherein when an error in measurement generated by eccentricity of a roller to which a carrying quantity measuring means such as a rotary encoder or the like is provided, is within a specific quantity, the error is neglected and only when it is the specific quantity or over, an image signal is corrected. CONSTITUTION:The title multiple color recorder is equipped with a control part 100 in which a difference between a marking detecting signal 4 generated by detecting a marking for control of a recording position and a carrier signal corresponding to a carried quantity of a recording sheet is compared with a set range preliminarily set and when the difference is within the set range, the number of lines to be recorded is not changed during the marking detecting signal and when it is outside the set range, the number of lines is increased or decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, forms images of different colors repeatedly on the same paper surface of a recording paper for each color and forms the image outside the screen along a non-image area of the recording paper. Control marks arranged in the recording paper feed direction,
The present invention relates to a multicolor recording apparatus of a type that controls the image recording position by reading this control mark.

[0002]

2. Description of the Related Art A multicolor recording apparatus for repeatedly forming images of different colors on the same surface of a recording paper for each color is put to practical use as a thermal transfer printer or an electrostatic color plotter. Has been done. In multi-color recording by these devices, if the positions of the images to be superimposed do not exactly match each other, color misregistration occurs and the quality of the formed image is significantly deteriorated. The above color misregistration occurs when the recording paper is reciprocated and expands and contracts due to the effects of tension, temperature, humidity, etc., and especially when forming a large-screen image, the effect becomes remarkable and cannot be ignored. Will be things.

As a solution to these problems,
For example, JP-A-57-122455 and Japanese Patent Publication No. 2-62.
As disclosed in Japanese Patent No. 863, etc., a mark for detecting a dimensional change due to expansion and contraction of the recording paper is provided on the recording paper, and by reading this mark, the dimensional change of the recording paper is detected and the line recording timing signal is adjusted. However, there is a method of forming recording dots at intervals that follow the expansion and contraction of the recording paper. However, in this method, it is necessary to calculate and change the recording period of the line for each mark, which makes the control circuit extremely complicated. Further, since the recording cycle determined by the calculation is not an integer, a color shift of about one line may remain in some cases.

Therefore, as disclosed in Japanese Patent Laid-Open No. 63-53071, a mark for detecting a dimensional change due to expansion and contraction of the recording paper is provided on the recording paper, and a line is formed at a predetermined constant recording period during this period. A method of printing and changing the number of lines according to the expansion and contraction of recording paper has been proposed. In this method, a signal corresponding to the amount of recording paper conveyed is output from the rotary encoder to print lines at a constant recording cycle.However, the roller that is directly connected to the rotary encoder and rotates with the conveyance of recording paper is eccentric. If so, an error corresponding to the eccentricity of the roller occurs in the recording cycle, and there is a possibility that unnecessary correction will be performed even if the recording paper does not expand or contract.

[0005]

As described above, the color misregistration in the conventional multicolor recording apparatus is caused by, for example, providing a timing mark for correcting the color misregistration at the time of recording the first color outside the image forming area of the recording paper. When recording and forming a color image of the second and subsequent colors, the timing marks for recording position control are read by optical means, and the expansion and contraction of the recording paper is performed so that the colors can be accurately overlapped even when the recording paper expands and contracts. It is prevented by correcting the image signal accordingly.

However, the recording interval of the timing mark is measured by a rotary encoder which measures the rotation amount of a roller that rotates in correspondence with the conveyance amount of the recording paper in a ratio of 1: 1. If the recording paper is aligned, even if the recording paper is not actually expanded or contracted, it is determined that the recording paper is expanded or contracted, the image signal is corrected, and color misregistration may occur.

The color misregistration correction method in the multi-color recording apparatus of the present invention has been made by paying attention to such a problem, and its object is to provide a conveying amount measuring means such as a rotary encoder. A multicolor recording apparatus capable of preventing unnecessary color misregistration correction by ignoring a measurement error caused by eccentricity of a roller within a predetermined amount and correcting the image signal for the first time when the measurement error is greater than the predetermined amount To provide.

[0008]

In order to achieve the above-mentioned object, the present invention provides a recording position control mask formed in a non-image recording area of a recording sheet along the transport direction of the recording sheet. −
In a color image forming apparatus for forming a multicolor image by controlling the superimposition of images for each color by the king, a means for detecting the formed marking and generating a marking detection signal, and a recording mark. -Based on a comparison between the marking detection signal and the carrier signal, a recording means for generating a carrier signal corresponding to the carriage amount of the recording medium, a recording means for recording each color image line by line on the basis of the carrier signal. And a control means for controlling the image recording position by increasing or decreasing the number of lines to be recorded between the marking detection signals, wherein the control means presets a difference between the marking detection signal and the carrier signal. If the difference is within the set range, the number of lines to be recorded between the marking detection signals is not increased or decreased. If the difference is outside the set range, the number of lines is increased or decreased.

[0009]

That is, in the present invention, the difference between the marking detection signal generated by the marking detection for recording position control and the carrier signal corresponding to the carry amount of the recording sheet is preset. If the difference is within the set range, the number of lines to be recorded between the marking detection signals is not increased or decreased. If the difference is outside the set range, the number of lines is increased or decreased.

[0010]

First, the outline of the present invention will be described with reference to FIG.

The multicolor recording apparatus according to the present invention uses the marking for controlling the recording position formed in the non-image recording area of the recording sheet along the conveying direction of the recording sheet, so that the image of each color is recorded. In a color image forming apparatus for controlling a superposition to form a multicolor image, a marking signal generating unit 4 for detecting a marking formed and generating a marking detection signal.
An encoder or pulse motor 51 that generates a carrier signal corresponding to the carry amount of the recording sheet, and a recording unit 5 that records each color image line by line based on the carrier signal.
A control unit 100 for controlling the image recording position by increasing or decreasing the number of lines to be recorded between the marking detection signals based on a comparison between the marking detection signal and the carrier signal. Reference numeral 100 compares the difference between the marking detection signal and the carrier signal with a preset range, and if the difference is within the preset range, increases or decreases the number of lines to be recorded between the marking detection signals. If it is out of the set range, the number of lines is increased or decreased. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic side view showing the overall construction of the first embodiment in which the present invention is applied to an electrostatic color plotter.
In FIG. 1, reference numeral 1 denotes an electrostatic recording paper roll, which is a roll around which a recording paper 2 is wound. The end portion of the recording paper 2 is led through a roller 3 to a recording system, a developing system, a recording paper winding system, and a cutting system. A rotary encoder 51 is connected to the roller 3 as shown in FIG.
A signal corresponding to the carry amount of the recording paper 2 is sent to the control unit 100. Reference numeral 5 denotes a multi-stylus electrostatic recording head that constitutes a recording system, and forms an electrostatic latent image on the recording paper 2 that moves in contact with the end surface of the recording head 2.

Numerals 6 to 9 are developing head groups constituting a developing system, and a plurality (four in this embodiment) of developing heads to which liquid developers of different colors are applied are arranged side by side. .. These developing heads 6 to 9 sequentially move up and down in synchronization with each reciprocating operation when a color image is formed while reciprocating the recording paper 2 a plurality of times as described later, and a predetermined color image is formed. It is supposed to be done.
Reference numeral 10 denotes a developer sucking roller installed on the downstream side of the developing head group, which sucks and removes the excess developing solution on the recording paper 2.

Reference numeral 11 is a recording paper feed roller, and a pressing roller 12 is in pressure contact with the surface thereof. The recording paper feed roller 11 has a guide plate 13 curved in an arc shape.
Is attached. Further, a recording paper guide guide plate 14 is arranged on the exit side of the recording paper feed roller 11.

Reference numeral 15 is a Y cutter for cutting the recording paper in a direction orthogonal to the recording paper feeding direction, and 16 is an X cutter for cutting the recording paper in a direction parallel to the recording paper feeding direction. The guide roller 1 is used to guide the recording paper 2 to these cutters.
7, 18, 19, 20, 21, 22 and guide plates 23, 24, 25 and the like are arranged.

Reference numeral 26 denotes a recording paper path switching guide lever, the base end of which is rotatably supported by a pin 27. The recording paper path switching guide lever 26 is
This is for switching whether to guide the leading edge of the recording paper 2 toward the automatic sheet winding device 30 or toward the Y cutter 15 and the X cutter 16.

Reference numeral 30 denotes a recording paper winding device, which is constructed so that the recording paper 2 guided and guided by the guide lever 26 can be automatically taken up. The automatic recording paper winding device 30 includes a winding roller 31 and a guide plate 3.
2. The pressure contact roller 33 and the like.

The electrostatic color plotter having the above construction operates as follows. First, prior to the start of recording, the recording paper 2 is pulled out from the recording paper roll 1, and the leading end of the recording paper 2 is set between the feed roller 11 and the pressure contact roller 12 and the guide rollers 17 and 18. The recording paper path switching guide lever 26 is set to a position for guiding the leading end of the recording paper 2 toward the automatic sheet winding device.

In this set state, the recording paper 2 is fed in the right-hand direction in FIG. 2 for forming the marking for controlling the recording position and forming the color image of the first color. Figure 4
The marking 40 for recording position control shown in is recorded on one side of the recording paper 2. Marking 40 for controlling the recording position
Is for detecting and correcting expansion and contraction of the recording paper 2 in the conveyance direction. At the time of forming a color image for the second and subsequent colors, the marking 40 for controlling the recording position is read by the optical means 4 so that even if the recording paper 2 expands or contracts, the colors can be accurately overlapped according to the expansion or contraction of the recording paper 2. The image signal is being corrected. In order to detect and correct the expansion and contraction of the recording paper 2 in the direction orthogonal to the conveying direction, the edges 41 and 42 of the recording paper 2 are also read by the optical means and the image signal is corrected according to the expansion and contraction. The details are omitted for the sake of simplicity.

When the multi-stylus electrostatic recording head 5 as the marking forming portion is operated while feeding the recording paper 2 in the right-hand direction in FIG. 2, the marking for controlling the recording position and the formation of the color image of the first color are performed. An electrostatic latent image is formed on the recording paper 2. This electrostatic latent image is developed by the developing head 6,
Any one of 7, 8, 9 may be used, for example, as the developing head 6
Can be converted into a toner image. The recording paper 2 is wound around the winding roller 31 by the action of the winding roller 31, the guide plate 32, and the pressure contact roller 33 of the automatic recording paper winding device 30. After this image formation is completed, the recording paper 2 is rewound onto the recording paper roll 1,
Preparation for the formation of the second color image is started. At this time, the recording paper 2 is not rewound until the front end is separated from the outer circumference of the winding roller 31, and only the front end is wound around the outer circumference of the winding roller 31. Leave it alone.

Then, the recording paper 2 is fed again in the right hand direction,
An electrostatic latent image for forming the second color image is formed on the recording paper 2 while using the recording position control marking 40 as a reference. This electrostatic latent image can be converted into a toner image by operating any one of the developing heads 7, 8, and 9, for example, by operating the developing head 7. During this period, the recording paper 2 whose front end is wound around the winding roller 31 is further wound around the winding roller 31.

By repeating the above-described operation, the images of the respective colors are superimposed on the same paper surface of the recording paper 2 with the markings for recording position control as a reference to form a color image.

At the time of recording the last color, the recording paper 2 is wound around the outer circumference of the take-up roller 31 as in the previous color.
After the image formation is completed, the recording paper 2 is rewound on the recording paper roll 1. At this time, the leading edge of the recording paper 2 is separated from the outer periphery of the take-up roller 31 and is rewound from the recording paper path switching guide lever 26 to the developing head side. After that, the recording paper path switching guide lever 26 moves the recording paper 2
The recording paper 2 is fed again, and the Y cutter 15 and X
By operating each of the cutters 16, the recorded recording paper 2 is cut into a desired size and discharged to the outside of the apparatus.

In the above arrangement, for example, the marking 40 for recording position control has a pitch of 4 mm and a recording density of 16
When the number of lines / mm is set, when the recording paper 2 is conveyed by 4 mm, 64 writing pulses are generated from the rotary encoder 51 directly connected to the roller 3.

The marking 40 for recording position control recorded on one side edge of the recording paper 2 in the first color is read by the optical means 4 and the 4 mm recording paper is conveyed during image formation in the second and subsequent colors. Each time one marking detection signal is generated. FIG. 5 shows how the image signal is corrected by the relationship between the writing pulse and the marking detection signal. In (a), the recording paper 2 does not expand or contract, and the marking signal is received once for 64 writing pulses, and the image signal is not corrected.

(B) shows the case where the recording paper 2 is contracted during the recording of the first color and the recording of the second color, and the next marking detection signal comes before the 64th write pulse comes. It's closed. In this case, the image signal is corrected by canceling the 64th image signal and moving to the first image signal to be recorded between the next marking detection signals.

(C) shows the case where the recording paper 2 is expanded during the recording of the second color with respect to the recording of the first color.
Although the printing of the fourth image signal has been completed and the next write pulse has come, the marking detection signal has not come yet. In this case, for example, the 64th image signal is printed as a dummy again, and after the next marking detection signal comes, the image signal is transferred to the first image signal to be recorded between the next marking detection signals. Is corrected.

The image signal is corrected as described above,
Here, it is assumed that the roller 3 is eccentric. For example, if the roller is about 30 mmφ
When there is an eccentricity of mm, a portion for generating 64 writing pulses even if the recording paper 2 is not conveyed by 4 mm,
A portion in which 64 writing pulses are not generated even if the sheet is conveyed by 4 mm or more occurs during one rotation of the roller 3,
Even if the recording paper 2 does not expand or contract as shown in,
The correction for increasing the main image signal and the correction for decreasing the single image signal occur at the pitch of the circumference of the roller 3.

As a countermeasure against this, the eccentricity of the roller 3 is set to 0.0.
It turned out to be much better if it was set to 6 mm or less,
Even so, unnecessary image signal correction still remains. Further, it is technically impossible to reduce the eccentricity of the roller 3.

Therefore, in the present invention, even if a correction signal of the image signal of an amount that may occur due to the eccentricity of the roller 3 is generated, the correction is not performed, and only when the correction signal of the image signal of a larger amount is generated. The correction was executed.

In the above example, the case where the roller 3 has an eccentricity of 0.1 mm is considered, but in this case, the eccentricity of the roller 3 may cause unnecessary correction for one image signal. Therefore, the correction for one image signal is executed only when the correction signal for two image signals is generated.

As a result, all unnecessary image signal corrections caused by the pitch of the circumference of the roller 3 disappeared, and only corrections corresponding to expansion and contraction of the recording paper 2 were observed.

Further, when a correction signal for three or more image signals is generated between one marking 40, it means that the expansion and contraction of the recording paper 2 is suddenly generated, but it seems that this is practically impossible. However, it is possible to consider that it is an erroneous detection of the marking 40 due to a fogging on the screen and to correct the image signal for one line. The second embodiment of the present invention will be described below.

In the first embodiment, the eccentricity of the roller 3 to which the rotary encoder 51 is directly connected is taken up as a factor that causes unnecessary correction of the image signal, but in the second embodiment, it is built in the machine. A system is used in which a pulse motor is driven by a pulse generator serving as a drive source, and the recording paper feed roller 11 directly connected to the pulse motor conveys the recording paper 2. Then, for example, if the pulse motor generates 64 writing pulses when a 4 mm recording sheet is conveyed, the rotary encoder 51 can be eliminated.

However, in that case also, the recording paper feed roller 11
Due to the eccentricity, unnecessary correction of the image signal may occur as in the first embodiment. In this case, just as in the first embodiment, even if the correction signal of the image signal of an amount that may be generated due to the eccentricity of the recording paper feed roller 11 is generated, the correction is not performed, and the correction signal of the image signal of the further amount By performing the correction only when the occurrence of the error occurs, it is possible to perform only the correction corresponding to the expansion and contraction of the recording paper 2.

As described above, in the present invention, the image signal is corrected only when the expansion / contraction of the recording paper, which exceeds the measurement error that may occur due to the eccentricity tolerance of the roller, is measured. As a result, even with a very simple configuration, even if a dimensional change occurs due to expansion and contraction of the recording paper, it is possible to accurately prevent the occurrence of color misregistration in the recording paper feed direction in a multicolor image.

[0037]

As described in detail above, according to the present invention,
If the measurement error caused by the eccentricity of the roller provided with means for generating a signal corresponding to the transport amount of the recording sheet such as a rotary encoder is within a predetermined amount, it is ignored, and it is over a predetermined amount. In this case, it is possible to provide a multicolor recording apparatus capable of preventing unnecessary color shift correction by correcting the image signal for the first time.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an outline of the present invention.

FIG. 2 is a schematic side view showing the overall configuration when the present invention is applied to an electrostatic color plotter.

FIG. 3 is a diagram showing a rotary encoder connected to a roller.

FIG. 4 is a recording position control marker recorded on one side of recording paper.
Diagram showing King.

5A, 5B, and 5C are views for explaining how the image signal is corrected by using the relationship between the write pulse and the marking signal.

6A and 6B are views for explaining an example in which a correction for increasing the single image signal and a correction for decreasing the single image signal occur even if the recording paper does not expand or contract.

[Explanation of symbols]

1 ... Electrostatic recording paper roll, 2 ... Recording paper, 3 ... Roller, 4 ...
Optical means, 5 ... Multi-stylus electrostatic recording head, 4
0 ... Marking, 51 ... Rotarian encoder, 100 ...
Control unit.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // B41J 11/00 B 9011-2C

Claims (4)

[Claims] 1. A recording sheet in a non-image recording area of the recording sheet.
In the color image forming apparatus for forming a multi-color image by controlling the superposition of images of respective colors by the marking for controlling the recording position formed along the conveyance direction of the image, the marking formed is performed. A means for detecting and generating a marking detection signal, a means for generating a carry signal corresponding to the carry amount of the recording sheet, and a recording means for recording each color image line by line based on the carry signal. Controlling the image recording position by increasing or decreasing the number of lines recorded between the marking detection signals based on a comparison between the marking detection signal and the carrier signal. Compares the difference between the marking detection signal and the carrier signal with a preset setting range, and if the difference is within the setting range, the number of lines to be recorded between the marking detection signals is not increased or decreased. , If it is out of the setting range, The image forming apparatus - color, characterized by performing the down count of the increase or decrease. 2. The means for generating the carrier signal is a rotary encoder, and the difference between the marking detection signal and the carrier signal is caused by the eccentricity of the roller to which the rotary encoder is connected. The multicolor recording apparatus according to claim 1, which is characterized in that. 3. The means for generating the carrier signal is a drive source for a pulse motor provided to carry the recording sheet, and the difference between the marking detection signal and the carrier signal is the pulse motor. 2. The multicolor recording apparatus according to claim 1, wherein the multicolor recording apparatus is caused by an eccentricity of a roller connected to. 4. A multicolor recording apparatus according to claim 1, wherein the number of lines increased or decreased between a pair of marking detection signals is within one line.