JPH07295392A - Image forming device - Google Patents

Abstract

PURPOSE:To surely provide a position information detecting mark on a belt with a simple constitution in an image forming device using a means detecting the position information of the belt such as an intermediate transfer belt. CONSTITUTION:In the image forming device having a detected member for detecting the position information (mark) 22 provided on the belt 10 and the means detecting the position information of the belt 10 with a detecting member provided on the side of a device main body, a sheet like member 21 having the detected member (mark) 22 in advance is attached to the belt 10. Since the position information detecting mark for the belt is provided on another sheet-like member beforehand instead of directly attaching the mark to the belt and the member is attached to the belt by adhesion, etc., adhesive area is made larger than that in the case where the mark is directly attached and the mark 22 can be surely attached to the belt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
The present invention relates to an image forming apparatus such as a facsimile.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus equipped with a belt-shaped photosensitive member, an intermediate transfer belt, etc., a mark, a cutout or the like is provided on the belt, and a detection member such as a photo sensor provided on the apparatus main body side. Belt position information is being detected. For example, Japanese Utility Model Laid-Open No. 61-34162 discloses an example in which a mark for detecting a seam of a photoconductor belt is formed on the photoconductor belt by thermal transfer of ink from a heat-meltable ink layer. However, in the thermal transfer forming method, the transferable target material is limited, and for example, due to its non-adhesive surface, it is transferred to a fluororesin (ETFE or the like) used for an intermediate transfer belt in a color image forming apparatus or the like. I can't. Further, even a transferable material is thermally transferred at a high temperature, so that the method of directly performing thermal transfer on the belt may affect the physical properties of the belt.

Further, Japanese Patent Laid-Open No. 60-134274 discloses an example in which notch portions for timing detection are provided on both sides of a photosensitive belt. In this invention, PET
(Polyethylene terephthalate) is the base of the photoreceptor belt, and even if a notch is provided at the end, deterioration such as cracking from the notch with time is small, but the fluororesin (ETFE) used for the intermediate transfer belt is small. Etc.), if the belt is repeatedly rotated with the notch provided at the end, cracks are likely to occur from the notch. That is, since there is a difference in mechanical strength depending on the material, the method of providing the cutout portion is restricted by the material of the belt and is not suitable for the intermediate transfer belt.

[0004]

By the way, as an example of a color image forming apparatus, an image for each color (for example, yellow, magenta, cyan, and cyan) is formed on a drum-shaped or belt-shaped photosensitive member.
Black) is formed, and images of respective colors are sequentially transferred onto the intermediate transfer belt and superposed on each other, and then transferred to transfer paper to form a color image. By providing a single mark or a plurality of marks on the intermediate transfer belt and detecting the marks to control writing, a positional deviation at the time of superimposing images is prevented.
One of the most commonly used intermediate transfer belts is the fluororesin ETFE belt as described above. However, the ETFE belt is much more non-adhesive due to the influence of its material (fluorine) than belts made of other materials, and a belt position detection mark must be provided on the belt by hot stamping, painting, printing, etc. Is difficult. Further, it has been attempted to adhere the position detection mark itself by a double-sided tape or the like, but the mark itself is curled, resulting in variations in detection by a detection unit such as a photo sensor. For this reason, in the color image forming apparatus using the intermediate transfer belt, in the method of detecting the mark on the intermediate transfer belt and controlling the alignment of each color as described above, the detection timing shift due to the mark stain, curl, etc. However, if there is variation, there is a problem in that there is a positional shift between the colors or color unevenness occurs.

Therefore, according to the present invention, in an image forming apparatus using a belt, particularly an intermediate transfer belt made of a fluorine resin, and using a means for detecting the position information of the belt, a mark for detecting the position information is surely provided on the belt. The purpose is to provide the mark with a simple structure. That is, the problem to be solved by the present invention is to ensure the attachment of the position information detection mark on the belt (photosensitive belt, intermediate transfer belt, etc.) in the image forming apparatus, and to attach the position information detection mark on the belt. Is to be easily and more strongly fixed, and the belt position information detection mark can be easily attached. still,
INDUSTRIAL APPLICABILITY The present invention is applied not only to the intermediate transfer belt and the photoconductor belt as described above, but also to various belts used in an image forming apparatus that detects position information and the like by a mark on the belt.

[0006]

In order to achieve the above object, the present invention provides a detected member (22) for detecting position information provided on a belt (10) and a detecting member provided on the apparatus main body side. An image forming apparatus having means for detecting the position information of the belt (10) by means of (24), a sheet-like member (21) provided with a detected member (22) in advance.
Is mounted on the belt (10) (claim 1). Further, the sheet-like member (21) is integrally provided over the entire circumference in the circumferential direction of the belt (10) (claim 2). The sheet-shaped member (21) is a reinforcing member for the belt (10) (claim 3).

[0007]

In the present invention, the member to be detected (position information detection mark) of the belt is not directly attached to the belt, but the member to be detected is provided in advance on another sheet-like member and the sheet-like member is attached to the belt. Therefore, the detection target member is securely attached to the belt. Further, by attaching one sheet-shaped member over the entire circumference in the circumferential direction of the belt, the sheet-shaped member can be attached to the belt more reliably, and the mark can be more strongly fixed on the belt. Further, by using the sheet-shaped member as the reinforcing member for the belt, it is possible to attach the detection target member with a simple structure without requiring a new work in the assembling process.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments. An embodiment of the color image forming apparatus of the present invention is shown in FIG. In FIG. 1, reference numeral 1 denotes a flexible belt-shaped photosensitive member (photosensitive belt) which is a belt-shaped image carrier, and the belt-shaped photosensitive member 1 is provided between rotating rollers 2 and 3 and is a rotating roller. It is conveyed clockwise by the drive of. Reference numeral 4 is a charging member serving as a charging means, 5 is a laser writing system unit serving as an image exposing means, and 6 to 9 are a plurality of developing means, that is, developing devices each containing a developer of a specific color. The laser writing system unit 5 is incorporated in the main body of the apparatus by being housed in a holding case having a slit-shaped exposure opening on the upper surface.
In addition to the illustrated laser optical system, the writing optical system 5 serving as the image exposing means may be an optical system in which a light emitting unit (LED or the like) and a convergent optical transmission body are integrated. Further, the charging member 4, the laser writing unit 5D for the photoconductor, and the photoconductor cleaning device 15 are provided at one roller 2 of the plurality of rollers that bridge the belt-shaped photoconductor 1. There is.

Each of the developing units 6, 7, 8 and 9 contains, for example, each of yellow (Y), magenta (M), cyan (C) and black developers, and the belt-like developer is provided at a predetermined position. Each developing sleeve is provided in proximity to or in contact with the photoconductor 1, and has a function of visualizing the latent image on the photoconductor belt 1 by non-contact development or contact development. Reference numeral 10 denotes an intermediate transfer belt which is a transfer image carrier, and the intermediate transfer belt 10 is provided between rotating rollers 11 and 12 and is conveyed counterclockwise by driving the rotating rollers 11 and 12. The belt-shaped photoconductor 1 and the intermediate transfer belt 10 are in contact with each other at the rotating roller 3, and the first visible image on the belt-shaped photoconductor 1 is bias roller 13 provided in the intermediate transfer belt. Is transferred onto the intermediate transfer belt 10. Then, by repeating the same process, the second-time visible image, the third-time visible image, and the fourth-time visible image are respectively overlapped on the intermediate transfer belt 10, and no positional deviation occurs. Is transcribed as. Further, a transfer roller 14 is provided so as to come into contact with and separate from the intermediate transfer belt 10, and a visible image superimposed on the intermediate transfer belt 10 is transferred onto a transfer paper at a contact portion with the transfer roller 14, that is, a transfer portion. Transferred by the roller 14. Reference numeral 15 is a cleaning device for the belt-shaped photosensitive member 1, which cleans the surface of the photosensitive member after the visible image is transferred onto the intermediate transfer belt 10. Reference numeral 35 is a charge eliminating lamp for eliminating charge on the surface of the photoreceptor after cleaning. Reference numeral 16 denotes a cleaning device for the intermediate transfer belt 10. The cleaning blade 16A of the cleaning device 16 is kept at a position separated from the surface of the intermediate transfer belt 10 during image formation, and is shown only during cleaning after the image is transferred onto the transfer paper. As described above, the intermediate transfer belt 10 is pressed against the surface.

The process of forming a color image by the color image forming apparatus having the above structure is performed as follows. First, the formation of a multicolor image according to this embodiment is performed according to the following image forming system. That is, the data obtained by the color image data input unit in which the image sensor scans the original image is
The image data processing unit performs arithmetic processing to create image data,
This image data is once stored in the image memory. Next, the image memory is taken out at the time of recording and is output to the recording unit, for example, the color image forming apparatus shown in the embodiment of FIG. That is, when a color signal output from an image reading device (not shown) separate from the printer is input to the laser writing system unit 5, the semiconductor laser (not shown) in the laser writing system unit 5 is inputted. ), The laser beam generated in step (a) is rotationally scanned by the polygon mirror 5B rotated by the drive motor 5A, and f
The optical path is bent by the mirror through the θ lens 5C to reach the laser writing unit 5D, and the charging member 4 serving as a charging unit is preliminarily used.
The peripheral surface of the belt-shaped photoconductor 1 that is uniformly charged by is exposed to form an electrostatic latent image. Here, the image pattern to be exposed is a monochromatic image pattern when the desired full-color image is separated into yellow, magenta, cyan, and black. The formed electrostatic latent images are developed by the rotary type developing devices by the developing devices 6 to 9 for yellow, magenta, cyan, and black, respectively, and visualized to form a monochromatic image. The monochromatic image formed on the belt-shaped photoreceptor 1 is transferred onto the intermediate transfer belt 10 which rotates counterclockwise while contacting the belt-shaped photoreceptor 1. That is, the yellow, magenta, cyan, and black single-color images formed on the photosensitive belt 1 are sequentially superposed on the surface of the intermediate transfer belt 10. Then, the multicolor image of yellow, magenta, cyan, and black superposed on the intermediate transfer belt 10 is fed from the paper feed table 17 by the paper feed roller 18 and conveyed to the transfer section via the conveyance roller and the registration roller 19. It is transferred to the transfer paper by the transfer roller 14. After the transfer is completed, the transfer paper is sent to the fixing device 20, and the image on the transfer paper is fixed by a heat fixing roller or the like of the fixing device 20 to complete a full-color image.

In the above image forming process, in order to align the images, a mark on the intermediate transfer belt 10 and / or the photoconductor belt 1 is detected by a detection member such as a reflection type photosensor provided on the apparatus main body side. The control is performed such that it detects and writes the image data. Generally, a mark is provided on the photoconductor belt side when the photoconductor belt has a seam, and on the intermediate transfer belt side when the photoconductor belt is seamless, but a mark is provided on both belts. I don't mind. Also, the number of marks on the belt may be one or more, but if a plurality of marks are provided,
Since the number of pieces of position information is plural, it is possible to detect the image position by counting marks, and to perform control such as writing image data according to the position information detected in the shortest time, thus increasing the printing speed. .

FIG. 2 is a perspective view of an intermediate transfer belt showing an embodiment of the present invention. In this embodiment, a sheet-like member having a certain length (less than the circumferential length of the belt), in which a member to be detected (mark for detecting position information) 22 is provided in advance on the side end portion of the intermediate transfer belt 10 in FIG. This is an example in which 21 is attached (Claim 1). That is, the detected member (mark) 22 for detecting the position information of the belt is not directly attached to the belt 10, but the detected member 22 is provided on another sheet-shaped member 21 in advance, and the sheet-shaped member 21 is attached to the belt. Since the member 10 is attached to the belt 10 with an adhesive or the like, the member 22 to be detected is reliably attached to the belt 10. In this case, as compared with the case where the mark is directly attached to the belt, the adhesion area is expanded, so that the mark can be reliably fixed on the belt.

Next, FIG. 3 is a perspective view of an intermediate transfer belt showing another embodiment of the present invention. In this embodiment, the sheet-like member 21 is attached to the belt 10 with an adhesive or the like over the entire circumference of one side end portion of the intermediate transfer bell 10 in FIG. 1, and the sheet-like member 21 is printed in advance. , A plurality of detected members (marks) 22 are provided at substantially equal intervals by coating, thermal transfer, or the like (claim 2).
2 and 3, in order to improve the detection accuracy of the position information by the detection member such as the reflection type photo sensor on the apparatus main body side, the sheet-shaped member 21 and the detected member 22 reflect as much as possible. It is better that the rates are different. As an example, the sheet-like member 21 is black, the detected member 22 is gold,
Silver or white is preferable. 4A is a plan view of a main part of the sheet-shaped member 21 attached to the intermediate transfer belt shown in FIG. 3, and FIG. 4B is a cross-sectional view of the main part of the sheet-shaped member 21. Detected member (mark) 2
In this example, 2 are provided at equal intervals, but the detected member (mark)
22 may be one (especially in the case of a photosensitive member with a seam). Further, FIG. 4B shows a sectional structure of the sheet-shaped member 21, which is composed of the detected member 22, the sheet-shaped member 21, and the adhesive 23 from above, and the sheet-shaped member 2
1 is adhesively fixed to the belt 10 by the adhesive 23.

The embodiment shown in FIG. 3 is an example in which the sheet-like member 21 shown in FIG. 4 is integrally provided in the circumferential direction of the belt 10 over the entire circumference. By mounting the belt 10 over the entire circumference thereof, the detected member (mark) 22 can be more firmly and reliably fixed to the belt 10, and there is no fear that the sheet-shaped member 21 is curled. In this case, the sheet-shaped member 21 can be used as a reinforcing member for the belt 10 (claim 3). In a fluororesin (ETFE) belt, which is a typical material for the intermediate transfer belt, a reinforcing member is often attached to the side end of the belt to prevent the belt from stretching and cracking. Excellent materials are used. Therefore, if the reinforcing member of the belt is used as the sheet-shaped member 21 and the member to be detected (mark) 22 is provided in advance on the sheet-shaped reinforcing member as shown in FIGS. When the reinforcing member is attached, the attachment of the detected member (mark) to the belt is completed at the same time.

FIG. 5 shows the outline of position information detection control in the image forming apparatus of the present invention.
A central processing unit that controls the sequence control of the control unit of the image forming apparatus by detecting the edge portion of the above-described detected member (mark) 22 for position information detection by a detection member 24 such as a reflection type photo sensor ( CPU 25), and the CPU sends a writing start signal to the writing unit 5 such as a laser optical unit and an LED unit. When four color developers (yellow, magenta, cyan, black) are used as in the above-described color image forming apparatus, a specific detected member (mark) 22 is detected for each color, Positioning is controlled by controlling writing and detecting four times in total.

Here, as an example, FIG. 6 shows an operation flow relating to position information detection during color image formation.
In FIG. 6, when the print is enabled, the CPU determines in step 100 whether a mark is detected by a detection signal from a detection member 24 such as a reflective photo sensor. If there is no mark, the process returns to step 100 with n, and step 100 is repeated until the mark is detected. When a mark is detected, the process moves to the next step 101 at y and the CPU
The value of the internal counter is set to, for example, 8 (when a plurality of marks are provided). At step 102, a write start signal is sent to the write unit at the same time. In step 103, it is determined whether the image formation of one printing plate (image formation for each color) is completed. If one printing plate is not finished, step 103 is repeated, and when one printing plate is finished, the process proceeds to step 104. In step 104, it is determined whether or not all the printing plates are finished. If it is not the final printing plate, the process proceeds to step 105 and it is determined whether the counter value has become 0. If the counter is not 0, step 105 is repeated. If 0, step 100
Return to and repeat the operation. Then, in step 104, it is determined whether or not all printing plates are finished, and if finished, the process ends.

The determination of the end of the 1st printing plate is determined by whether or not the count value becomes 0 by the countdown by the down counter by the interrupt routine shown in FIG. Also, in the interrupt routine, the count is decremented by 1 each time the mark is detected. That is, when a plurality of marks 22 are provided on the belt at substantially equal intervals as shown in FIG. 3, if the number of marks corresponding to the maximum print size of one printing plate is set as a counter value, one mark detection is performed. The count is decremented by 1 each time, and when the count value becomes 0, it is determined that the 1st printing plate end.

In the above embodiment, the mark is provided on the intermediate transfer belt (and / or the photoconductor belt), but the present invention is not limited to the above-mentioned intermediate transfer belt and photoconductor belt, and the mark on the belt may be used. It is applied to various belts used in an image forming apparatus that detects position information and the like.

[0019]

As described above, in the image forming apparatus according to the first aspect, the detected member (mark) for detecting the belt position information is not directly attached to the belt, but is previously attached to another sheet-shaped member. Since the mark is provided and the sheet-shaped member is attached by adhering it to the belt, the adhesion area is wider than when the mark is directly attached,
The mark can be surely attached on the belt.

In the image forming apparatus according to the second aspect, since one sheet-shaped member is attached over the entire circumference of the belt, the sheet-shaped member can be attached to the belt more reliably and can be more strongly attached to the belt. The mark can be fixed.

In the image forming apparatus of the third aspect, the sheet-shaped member is a reinforcing member for the belt, and the position information detection mark is provided in advance on the reinforcing member. Marks can be attached with a simple structure without requiring work,
The cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a perspective view of an intermediate transfer belt showing an embodiment of the present invention.

FIG. 3 is a perspective view of an intermediate transfer belt showing another embodiment of the present invention.

4A is a plan view of relevant parts of a sheet-shaped member attached to the intermediate transfer belt or the like shown in FIG. 3, and FIG. 4B is a sectional view of relevant parts of the sheet-shaped member.

FIG. 5 is a diagram showing an outline of position information detection control in the image forming apparatus of the present invention.

FIG. 6 is a flowchart illustrating an example of position information detection operation when forming a color image.

FIG. 7 is a flowchart showing an interrupt routine for determining the end of the first printing plate in the operation flow shown in FIG. 6;

[Explanation of symbols]

 1: Belt-shaped photoconductor (photoconductor belt) 2, 3: Rotation roller 4: Charging roller 5: Laser writing system unit 5A: Drive motor 5B: Polygon mirror 5C: fθ lens 5D: Laser writing unit 6: Y developing unit 7: M developing unit 8: C developing unit 9: Black developing unit 10: Intermediate transfer belt 11, 12: Rotating roller 13: Bias roller 14: Transfer roller 15: Photoconductor cleaning device 16: Intermediate transfer belt cleaning device 16A : Cleaning blade 17: Paper feed table 18: Paper feed roller 19: Registration roller 20: Fixing device 21: Sheet-like member 22: Detected member (mark) 23: Adhesive agent 24: Detection member (reflection type photosensor, etc.) 25 : Central processing unit (CPU)

Front page continuation (72) Inventor Takahiro Tamiya 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd.

Claims (3)

[Claims] 1. An image forming apparatus comprising a detected member for detecting positional information provided on a belt and a means for detecting positional information of the belt by a detecting member provided on the main body of the apparatus. An image forming apparatus, wherein a sheet-shaped member provided with is attached on the belt. 2. The image forming apparatus according to claim 1, wherein the sheet-shaped member is integrally provided over the entire circumference in the circumferential direction of the belt. 3. The image forming apparatus according to claim 2, wherein the sheet-shaped member is a belt reinforcing member.