JP2009265167A - Color image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color image forming apparatus capable of automating the process of minimizing toner consumption for color shift correction by using only a large inspection image only when it is required, and using a smaller inspection image in other cases. <P>SOLUTION: Based on pre-stored inspection images in which a pattern of a plurality of monochrome colors is repeated in a sub-operating direction, the color image forming apparatus forms toner images of monochrome colors corresponding to the inspection images to an intermediate transfer body or a photoreceptor. The apparatus detects intervals between the patterns composing the toner images of the monochrome colors in the sub-operating direction, and thereby inspects a color shift during transfer. The apparatus stores two or more inspection images of different areas where one is larger than the other, and selectively uses these inspection images according to situations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color image forming apparatus capable of improving the accuracy of automatic color misregistration correction.

  2. Description of the Related Art Conventionally, in a color image forming apparatus, an electrostatic latent image on a photosensitive member obtained by light-modulating a laser beam on a photosensitive member such as a photosensitive drum according to recorded image data is developed with toner. And a plurality of recording devices for forming toner images on a transfer material such as transfer paper or an intermediate transfer belt, and these recording devices can transfer a plurality of single color images onto the transfer material or perform intermediate transfer. After a plurality of single color images are transferred onto a belt, the final color image is formed by collectively transferring the images onto a transfer sheet.

In this type of color image forming apparatus, it is formed on the photosensitive member due to the above-described mounting error between recording apparatuses, optical path length error of the laser beam light, optical path change, warpage due to the ambient temperature of the light source LED. In some cases, so-called color misregistration may occur, in which the positions of the single color images to be transferred do not coincide with each other on the transfer material to be finally multiplex-transferred.
In order to correct this color misregistration, conventionally, an inspection image in which a pattern composed of a plurality of single-color colors is repeated in the sub-scanning direction is stored in advance, and the inspection image is transferred onto the photoreceptor or the transfer belt based on the inspection image. A color toner image corresponding to the image is formed, and the color misalignment at the time of development is inspected by detecting the interval in the sub-scanning direction of the pattern constituting the color toner image with a photosensor such as a CCD or PD. A color image forming apparatus in which the optical path length is automatically corrected in accordance with the amount of color misregistration is known from, for example, Japanese Patent Application Laid-Open No. H10-228707.
JP 2003-149907 A

In the conventional color misregistration correction method as described above, an actual toner image corresponding to the inspection image is formed on the photosensitive member or the intermediate transfer belt, and the toner is consumed for the inspection. The amount of consumption becomes a problem. The amount of toner consumption increases as the inspection image becomes larger. Therefore, it is desirable to reduce the area of the inspection image in order to reduce toner consumption.
However, in practice, if the area of the inspection image is reduced, the outline of the toner image is blurred, and the inspection accuracy is inevitably lowered. In order to avoid this, the inspection image may be enlarged. However, as described above, the toner consumption cannot be reduced.

  Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to use a large inspection image only when a large inspection image must be used, and to reduce the size otherwise. An object of the present invention is to provide a color image forming apparatus capable of automating the process of reducing toner consumption as much as possible at the time of color misregistration correction by using an inspection image.

In order to achieve the above object, a color image forming apparatus according to the present invention comprises:
Forming a single color toner image corresponding to the inspection image on the intermediate transfer member or the photosensitive member based on a previously stored inspection image in which a pattern constituted by a plurality of single color is repeated in the sub-scanning direction; In a color image forming apparatus in which color misregistration at the time of transfer is inspected by detecting an interval in the sub-scanning direction of the pattern constituting a single color toner image.
The color image forming apparatus stores two or more types of inspection images having a large or small area as the inspection image, and uses the two or more types of inspection images depending on the situation.
The situation may be the first inspection after replacing the recording device that forms the electrostatic latent image on the photosensitive member, and the inspection from the shipment of the color image forming apparatus to the first recording device. In this case, the proper use according to the situation is that an inspection image with a large area is used for the first inspection after the recording device is replaced, and a small area is required between the shipment from the factory and the replacement of the first recording device. One that uses an inspection image is conceivable.
As another situation, there may be a first inspection after replacing a recording device for forming an electrostatic latent image on the photosensitive member and a subsequent inspection. In this situation, it is conceivable that the inspection image having a large area is used for the first inspection after replacing the recording apparatus, and the inspection image having a small area is used for the subsequent inspection.
As another situation, it can be considered when an abnormality is detected in the inspection and when no abnormality is detected. In this case, it is conceivable that the inspection image having a large area is used when an abnormality is detected in the inspection, and the inspection image having a small area is used when no abnormality is detected.

  According to the present invention, a single color toner corresponding to the inspection image is formed on the intermediate transfer member or the photosensitive member based on a previously stored inspection image in which a pattern constituted by a plurality of single color is repeated in the sub-scanning direction. In a color image forming apparatus configured to inspect color misregistration during transfer by forming an image and detecting an interval in the sub-scanning direction of the pattern constituting the single color toner image, A color image forming apparatus that stores two or more types of inspection images having large and small areas and uses the two or more types of inspection images depending on the situation is grasped. As a result, a large color misregistration may occur. For example, immediately after the recording device is replaced or when the error of the color misregistration pattern interval is large, the inspection accuracy must be increased. Therefore, a large inspection image that can increase the inspection accuracy is used, and a small inspection image that consumes less toner is used at the time of shipment from the factory, which is considered to have no other large color shift, or during normal inspection. In this way, since a large and small inspection image is used according to the color misregistration situation, a high level color misregistration inspection can be performed while suppressing toner consumption.

Hereinafter, an embodiment in which the present invention is applied to a color multifunction peripheral, which is an example of a color image forming apparatus, will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a block diagram showing the configuration of the main part of the color MFP X according to the embodiment of the present invention, and FIG. 2 shows the color misregistration correction procedure executed by the main control unit 1 in the color MFP X. FIG. 3 is a flowchart illustrating an example of an inspection image, and FIG. 4 is a diagram illustrating an inspection image having a small area and a large inspection image.

First, the configuration of the main part of the color multifunction peripheral X according to the embodiment of the present invention will be described with reference to the block diagram shown in FIG.
The color multifunction machine X can be replaced with a copying machine, a printer, a facsimile machine, and other image forming apparatuses.
The color multifunction peripheral X according to the embodiment of the present invention has a function of performing print processing based on print data related to page images for a plurality of pages stored in advance in a data storage unit such as a hard disk.
That is, as shown in FIG. 1, the color multifunction peripheral X includes a main control unit 1, an operation / display unit 2, a data storage unit 3, an image processing calculation unit 4, a NIC 5, a scanner unit 6, a printing unit 7, and a facsimile unit 8. Etc., and they are connected in a state where information can be exchanged through the bus 11.

The operation / display unit 2 includes an operation unit 2a for inputting information and a display unit 2b for displaying information (including images). The operation unit 2a is, for example, a touch panel or a sheet key provided on the surface of the liquid crystal display device. The display unit 2b is, for example, a liquid crystal display device. The operation / display unit 2 constitutes a man-machine interface for the user.
The data storage unit 3 is a readable / writable large-capacity non-volatile memory that stores processing data as necessary when processing image data obtained by reading from a document or printing processing of image data. .
An inspection image in which a pattern composed of a plurality of single color colors in the present invention is repeated in the sub-scanning direction is stored in advance in the data storage unit 3.

  In addition, the data storage unit 3 stores in advance a reference pattern interval length serving as a reference for determining whether a detected pattern interval, which will be described later, is normal or abnormal, or variations in the interval length. Yes.

There are two types of inspection images, large and small, and FIG. 3 shows the smaller inspection image TEST-S.
As shown in the figure, the inspection image TEST-S is formed at portions corresponding to both sides of the transfer belt B in the width direction, and an oblique pattern row and a pattern row parallel to the main scanning direction are formed in the sub-scanning direction. Are alternately arranged.
FIG. 4A is an enlarged view of the pattern row, and is composed of a plurality of monochrome colors (black, yellow, cyan, magenta) set to a width a in the sub-scanning direction and arranged at intervals d. An oblique pattern P1S and a pattern P2S in the main scanning direction are formed, and this pattern is repeatedly formed in the sub-scanning direction like P1S, P2S, P1S, P2S. In this example, the interval between the patterns P1S and P2S is set to a constant k.
FIG. 4A shows a small inspection image TEST-S of the two types of large and small inspection images as described above, but the large inspection image TEST-L is slanted as shown in FIG. 4B. The width of the pattern P1L (P2L) (and in the main scanning direction) is set to twice the width a of the pattern P1S (P2S), that is, 2a, and the interval in the sub-scanning direction between the patterns is also doubled to 2d. ing. Also, the interval between the pattern rows is doubled to 2k.

  The image processing arithmetic unit 4 is constituted by a dedicated signal processing circuit or a DSP (Digital Signal Processor) or the like, performs various image processing on the image data, and forms a print job described in a predetermined print job description language into an image. A process for converting to bitmap image data to be used, a process for generating image data to be transmitted to an external device (for example, image data subjected to predetermined encoding such as JPEG format), and the like are performed.

The NIC 5 receives data (including data of an image read by the scanner unit 6) with an external device such as an information processing terminal or an e-mail server through a network including a LAN and the Internet conforming to the standard IEEE 802.3, for example. It is a communication interface which transmits / receives.
The scanner unit 6 converts an image formed on a document from a document placed on a glass document table (not shown) or a document conveyed by an ADF (not shown) to a color (R, G, B). ) Is a color scanner that distinguishes and reads.

The print unit 7 is a so-called print engine controlled by the main control unit 1, and sequentially feeds recording sheets stored in a sheet feeding cassette (not shown) one by one, and passes through a predetermined image forming position to a sheet discharge tray. Recording paper (recording paper) based on the image data of the original read from the original by the scanner unit 6 and the image data for printing generated by the image processing calculation unit 4 at the image forming position. It is a set of components such as a device that forms (outputs) an image on an example) and an MPU that controls the device. The printing unit 7 has a function of executing double-sided printing processing for forming an image on both the front surface and the back surface of the recording paper.
An image of a single color toner corresponding to the inspection image is formed on an intermediate transfer member or a photoconductor based on an inspection image in which a pattern constituted by a plurality of single color is repeated in the sub-scanning direction. This processing is also executed in the print unit 7.
The facsimile unit 8 includes communication means such as an NCU (Network Control Unit) and a modem, and performs dial-up and negotiation processing for determining a communication method with a communication partner (partner station). It transmits and receives facsimile data (image data read by the scanner unit 6) with the facsimile apparatus.

The main control unit 1 controls each of the scanner unit 6, the print unit 7, the facsimile unit 8, the operation / display unit 2, the data storage unit 3, and the image processing calculation unit 4.
For example, the main control unit 1 causes the printing unit 7 to execute a printing process (image forming process) based on a print job received through the NIC 5. Further, the main control unit 1 causes the facsimile unit 8 to execute a facsimile transmission process for calling a designated transmission destination telephone number and transmitting image data to be transmitted. Further, the main control unit 1 causes the scanner unit 6 to execute a scanning process for reading an image formed on the original from the original.
The main control unit 1 also has the inspection image on the intermediate transfer member or the photosensitive member based on the inspection image in which the pattern formed by the plurality of single color colors generated by the image processing calculation unit 4 is repeated in the sub-scanning direction. The printing unit 7 is instructed to form a single color toner image corresponding to.

Next, the procedure of color misregistration correction processing executed by the color multifunction peripheral X will be described with reference to the flowchart shown in FIG. 2 and the charts shown in FIGS.
This color misregistration correction processing is roughly performed on the intermediate transfer member or the photosensitive member based on a previously stored inspection image TEST in which patterns P1, P2, P1, P2,. Forming a single color toner image corresponding to the inspection image TEST, and detecting an interval in the sub-scanning direction of the pattern constituting the single color toner image to inspect a color shift at the time of transfer. Sometimes, as the inspection image, two or more types of inspection images TEST-S, TEST-L,... Are stored, and the two or more types of inspection images are selectively used according to the situation as described below. Is. This will be described in detail below.
In the following description, S1, S2,... Are identification codes of color misregistration correction processing procedures executed by the main control unit 1.
The process shown in FIG. 2 is started by an instruction to start a color misregistration correction procedure from the operation / display unit 2 or an instruction in a separate inspection process at the factory.
When the color misregistration correction procedure starts, that is, when there is an inspection instruction (Yes in S1), the main control unit 1 determines whether or not it is currently in the initial installation (S2). Initial installation refers to work when a new color multifunction peripheral is first used after being purchased by a user.
Since the initial installation is executed based on the initial installation program at the time of the initial installation work, the main control unit 1 can naturally determine whether or not the current time is the initial installation.
If it is not at the time of initial installation, the color multifunction peripheral is in a state of being delivered to the user and used (normal time). It is determined whether or not the first inspection has been performed (immediately after the recording apparatus replacement) (S3).
Whether or not the recording device having the photosensitive member or the processing unit including the photosensitive member is to be replaced is information that can be detected by the main control unit 1 by various methods, such as whether or not power is supplied to the recording device.

Here, when it is determined that the current state is immediately after the recording apparatus is replaced (Yes in S3), the process proceeds to S10.
If it is determined that it is not immediately after the recording apparatus is replaced (No in S3), the main control unit 1 continues to check two types of inspection images TEST-S stored in the data storage unit 3. , TEST-L, the smaller inspection image TEST-S (see FIG. 4A) is read from the data storage unit 3 (S4), and the patterns P1S, P2S, P1S, P2S of the inspection image TEST-S are read out. .., Patterns P1S, P2S, P1S, P2S,... Are formed on the intermediate transfer belt B (S5).
The intervals of the formed patterns P1S, P2S, P1S, P2S,... Are detected by optical sensors such as CCD and PD (not shown) as the intermediate transfer belt B travels (S6).

The main control unit 1 uses the intervals (or variations) of the patterns P1S, P2S, P1S, P2S,... Detected in this way as the reference pattern interval length (or variation thereof) as a reference stored in the data storage unit 3. ), It is determined whether the interval between the patterns P1S, P2S, P1S, P2S,... Is within the reference pattern interval length (or variation thereof) (S7).
Here, when it is determined that the interval between the patterns P1S, P2S, P1S, P2S,..., That is, the interval between the patterns P1S, P2S, P1S, P2S,... Is normal (Yes in S7), Since the inspection using the small inspection image obtained in step S6 is considered sufficient, the pattern formed in S5 is detected by the CCD or PD, and the color misregistration amount of each color is detected based on the data (S8). Positioning correction such as changing the image writing timing is performed (S9), and the process is terminated.

On the other hand, in S7, the interval between the patterns P1S, P2S, P1S, P2S,... Is longer than the reference pattern interval length, that is, the interval between the patterns P1S, P2S, P1S, P2S,. If it is determined that it is short (or the variation thereof is large) (No in S7), it is evaluated that a clear deviation amount cannot be determined with a standard small inspection image such as that employed in S4 to S6. Therefore, a large inspection image as shown in FIG. 4B is read from the data storage unit (S10), and a large inspection image is formed.
The subsequent processing (S8, S9) is the same as the case where the pattern interval is determined to be normal in S7, and the color misregistration amount of each color is detected based on the pattern formed in S11 (S8). Positioning correction, such as changing the timing of writing the recorded image, is performed (S9), and the process ends.
In this way, the size of the inspection image can be used properly depending on whether an abnormality is detected or not detected in the inspection, but it is rare that an abnormality is detected. In normal operation, a small inspection image can be used to reduce toner consumption, and in rare cases, a large inspection image is used. Correction can be realized.

  In addition, as described above, also when it is determined that the recording apparatus has been replaced (Yes in S3), the process proceeds to S10, where a large inspection image is used, but the recording apparatus is replaced. Since it is rarely performed, the use of a small inspection image usually suppresses toner consumption, and a large inspection image is used only when the recording apparatus is replaced. Correction is realized.

  In this embodiment, a small inspection image is used at the time of initial installation, that is, at the first use when the color multifunction peripheral is shipped from the factory (Yes in S2), or immediately after replacement of the recording device (Yes in S3). Or use large inspection images. This is because the high-accuracy inspection at the factory is completed immediately after the color MFP is shipped from the factory, so it is set to a sufficiently high precision so that color misregistration correction is not necessary. This is because it is desirable to use a large inspection image because it is highly likely that a large color shift has occurred immediately after replacing the recording apparatus as described above.

  The present invention can be used for a color image forming apparatus such as a color copying machine, a color printer, a color facsimile, or a color complex machine employed in this embodiment.

1 is a block diagram illustrating a configuration of a main part of a color multifunction peripheral X according to an embodiment of the present invention. 5 is a flowchart showing a color misregistration correction procedure executed by a main control unit 1 in the color multifunction peripheral X. The figure showing an example of a test | inspection image. The figure which shows a small inspection image and a large inspection image.

Explanation of symbols

X: Image forming apparatuses TEST-S, TEST-L ... Inspection images P1S, P2S, P1L, P2L ... Pattern 1: Main control unit 3: Data storage unit 4: Image processing calculation unit 5: NIC (network interface card)
S1, S2,...: Identification symbols of processing procedures (steps)

Claims (4)

Forming a single color toner image corresponding to the inspection image on the intermediate transfer member or the photosensitive member based on a previously stored inspection image in which a pattern constituted by a plurality of single color is repeated in the sub-scanning direction; In a color image forming apparatus in which color misregistration at the time of transfer is inspected by detecting an interval in the sub-scanning direction of the pattern constituting a single color toner image.
A color image forming apparatus in which two or more types of inspection images are stored as the inspection image, and the two or more types of inspection images are selectively used according to the situation.   The above situations are the first inspection after replacing the recording device that forms the electrostatic latent image on the photosensitive member, and the inspection from the factory shipment of the color image forming apparatus to the replacement of the first recording device. The use of a large area inspection image is used for the first inspection after replacing the recording device, and a small area inspection image is used from the factory shipment to the replacement of the first recording device. The color image forming apparatus according to claim 1.   The situation is the first inspection after replacing the recording device that forms the electrostatic latent image on the photosensitive member and the subsequent inspection, and the proper use according to the situation is the first after the recording device is replaced. 2. A color image forming apparatus according to claim 1, wherein an inspection image having a large area is used for the inspection, and an inspection image having a small area is used for the subsequent inspection.   The situation is when an abnormality is detected in the inspection and when no abnormality is detected, and the proper use according to the situation uses an inspection image of a large area when the abnormality is detected in the inspection, 2. The color image forming apparatus according to claim 1, wherein when no abnormality is detected, an inspection image having a small area is used.

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