JP2793721B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for synthesizing toner images of a plurality of original images and transferring the synthesized images to a sheet.

[0002]

2. Description of the Related Art In a conventional full-color copying machine, when a color original is copied, color images are color-separated to sequentially form yellow, magenta, and cyan toner images on a photoreceptor.
Each toner image formed on the photoreceptor is superimposed on a transfer medium to synthesize a color image, which is transferred to paper and then fixed.

Another conventional full-color copying machine is configured such that the transfer medium is omitted, and the toner images on the photoreceptor are directly superimposed on paper to synthesize and fix the color images. I have.

A conventional black-and-white copying machine, as shown in FIG. 10, forms a black toner image on a photoreceptor 31, transfers it to a sheet, and then fixes it on the sheet by a fixing unit 32. Have been.

[0005]

However, since the above-mentioned conventional full-color copying machine and black-and-white copying machine are configured to copy the image of one document, the images of a plurality of documents are synthesized. When transferring to a sheet, the next document image is transferred to the sheet on which the previous document image has been fixed. Therefore, there is a problem that the accuracy of the position of each image is low and the transfer time is long.

Particularly, in a full-color copying machine equipped with a transfer medium, the photosensitive member and the transfer medium are always in contact with each other and rotate and stop. Therefore, when the speeds of the photosensitive member and the transfer medium do not match, each image matches. There is a problem that it does not.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in conventional full-color copying machines and black-and-white copying machines, and it is an object of the present invention to improve the alignment accuracy of each image when combining and transferring images of a plurality of originals onto paper. Provided is an image forming apparatus capable of reducing the synthesis time.

[0008]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a photoreceptor for forming a plurality of toner images corresponding to an image of a document ; and an image forming area and a non-image forming area. comprising a transfer medium to synthesize bets toner image of the multiple toner image formed on a photosensitive member by superimposing transferred to the image forming area by facing the movement, and control means for controlling the facing movement of said transfer medium and has, wherein, for each of the plurality of bets <br/> toner image is superimposed and transferred to the transfer medium, the non-image forming region of the contact points of the transfer medium and the transfer medium and the photosensitive member stop the transfer medium so as to be positioned, then, before the time of rising of the superimposed transfer of the formation and the transfer medium in the photosensitive member on the Quito toner image, wherein the contact point of the transfer medium image The photoconductor and the photoconductor when reaching the formation area To match the movement speed of the copy medium, the so tip required distance from the image forming region of the transfer medium is obtained, the image type of the contact points the transfer medium
To the non-image forming area end of the tip side of the formation region, wherein the multiple moving the transfer medium in a direction opposite to the moving direction during image formation
It is configured to align the bets toner image.

[0009]

[0010]

[0011]

[Action] The claim 1 of the image forming apparatus, a plurality of bets toner image formed on the photoreceptor sequentially superimposed and transferred on the image forming region of the transfer medium by facing the movement, control means, a plurality of bets Na < each time br /> over image is superimposed and transferred onto the transfer medium, the contact point between the transfer medium and the photosensitive member stop the transfer medium so as to be located in a non-image forming region of the transfer medium, then the toner image In order to match the moving speed of the photoconductor and the transfer medium when the contact point reaches the image forming area of the transfer medium at the time of formation on the photoconductor and the start of the superimposed transfer onto the transfer medium, So that the required distance is obtained from the leading edge of the image forming area of the transfer medium.
Until the non-image forming region end edge side, the moving direction during image formation to form a composite toner image aligns the multiple toner image to move the transfer medium in the reverse direction.

[0012]

[0013]

[0014]

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

FIG. 1 shows an electric system of a full-color copying machine provided with an embodiment of an image forming apparatus according to the present invention.

As shown in FIG. 1, a CPU (Central Processing Unit) 11 is configured to perform control and the like when combining images of a plurality of documents and transferring the images to a sheet, as will be described later. The program of the CPU 11 is stored in a ROM (read only memory) 12 in advance.

A RAM (random access memory) 13
Area or CPU for storing predetermined adjustment values of copier
It has 11 work areas. The RAM 13 has a battery 14
The data can be retained even if the power is turned off.

An I / O (input / output) unit 15 includes an operation unit 16 for performing various operations of the copying machine shown in FIG.
PC motor 17 for transporting a photoreceptor (described later) on which an image is formed
a, an encoder 17 for detecting the rotational position of the PC motor 17a
b, a transmission type PC index sensor 17c for detecting the position of the photoreceptor, and a TX motor 18 for transporting a transfer medium (described later) on which a toner image of the photoreceptor is transferred and capable of synthesizing a plurality of images.
a, an encoder 18 for detecting the rotational position of the TX motor 18a
b, a transmission type TX index sensor 18c for detecting the position of the transfer medium, and other loads and a sensor 19 are connected.

Operation information of the operation unit 16, encoders 17b and 18
b, each detection information of the sensors 17c and 18c is an I / O unit
CPU 15 is notified via 15. Also, the PC motor 17
a, TX motor 18a is I / O unit by CPU11
Controlled via 15.

As shown in detail in FIG. 2, the operation unit 16 includes a black and white copy button 16a for selecting a black and white copy, a color copy button 16b for selecting a color copy, and a plurality of original images. A synthesis mode button 16c for selecting a mode for synthesizing is provided.

Next, a detailed configuration of the mechanical system will be described with reference to FIG.

A color or black-and-white document 21 is placed on a document table 22 such that the image is turned face down. The image of the document 21 is irradiated by an exposure lamp 23, separated into three primary colors by an optical filter 24, and led to an exposure position A of a PC belt 26 as a photosensitive member via a lens 25 and the like.

An MHV unit 27 for charging the surface of the PC belt 26 in advance before exposure is disposed upstream (right side in the figure) of the exposure position A of the PC belt 26, and downstream of the exposure position A of the PC belt 26 ( A blank lamp unit 28 for sequentially removing unnecessary charges on the surface of the PC belt 26 to form voids and the like at the time of copying is provided on the left side of FIG.
Magenta (M), cyan (CY), and black (B) toners
Tank for visualizing each electrostatic latent image
29Y, 29M, 29CY, 29B and toner on PC belt 26
TX belt 30, which is the medium on which the image is transferred at position B
Is arranged.

With respect to the TX belt 30, a sheet (not shown) is conveyed to the left from a sheet cassette 31 on the right side in the figure.
The toner image transferred from the TX belt 30 to the paper is fixed to a fixing device 32.
Is fixed by

The PC belt 26 and the TX belt 30 are rotated counterclockwise and clockwise by the PC motor 17a and the TX motor 18a shown in FIG. 1, respectively, and position detection is performed as shown in FIG. An index) slit 26a, 30a is formed on the edge. The slits 26a and 30a are respectively a transmission type PC index sensor 17c shown in FIG.
The detection is performed by the TX index sensor 18c, and control is performed so that the leading end of the image area on the TX belt 30 coincides with the contact point between the PC belt 26 and the TX belt 30, that is, the transfer position B with reference to the slit 30a of the TX belt 30.

The paper is transported by a motor (not shown), which is similarly controlled by the CPU 11. Each of the PC belt 26 and the TX belt 30 has a width and a length capable of forming an image of a maximum paper size (11 × 17 inches).

Next, the operation of the mechanism shown in FIG. 3 will be described.

In the case of color copying, a document on the platen 22
The image 21 is scanned three times and is separated into three primary colors by the optical filter 24, and an electrostatic latent image of each color is formed on the PC belt 26 for each scan. The electrostatic latent image on the PC belt 26 is
Of the optical filters 24, one of the yellow developing tank 29Y, the magenta developing tank 29M, and the cyan developing tank 29CY having a complementary color relationship to the used filter is visualized, and each toner image is sequentially formed on the TX belt 30. It is superimposed and transferred on top.

In the case of color copying, the black developing tank 29B is used.
Is not used, and in the case of black and white copying, the image of the original 21 on the original platen 22 is scanned once, and the electrostatic latent image on the PC belt 26 is visualized only by the black developing tank 29B. A black toner image is transferred onto the TX belt 30.

FIG. 5 is a flowchart showing the operation of the CPU 11 when synthesizing a plurality of original images.

Hereinafter, the flowchart of FIG. 5 will be described.
Various modes set by the operation unit 16 are processed to
AM13 is set (step S1), and copying is started (step S2). Next, it is determined whether or not the combination mode is set in the RAM 13 (step S3), and the combination mode is determined.
If no password has been set, the process proceeds to step S4, and P
After the rotation of the C motor 17a and the TX motor 18a is started and the PC belt 26 and the TX belt 30 reach predetermined end positions in the image area, the toner image is displayed on the PC belt 26 and the TX belt 30. (Step S5).

On the other hand, in step S3, the synthesis mode
PC mode 17a, TX mode
It is determined whether or not the motor 18a is rotating (step S6). If the motor is not rotating, the rotation of the PC motor 17a and the TX motor 18a is started (step S4). If the motor is rotating, a toner image is formed on the PC belt 26 and the TX belt 30. (Step S5).

Subsequently, it is determined again whether the combination mode is set in the RAM 13 (step S7), and the combination mode is determined.
If the password has been set, the process returns to step S1. On the other hand, if the composite mode is not set, the motor for transporting the sheet is driven to transfer the toner image on the TX belt 30 onto the sheet (step S8). Finally PC motor 17
a, The rotation of the TX motor 18a is stopped (step S9),
It returns to step S1. Accordingly, the composite toner image transferred onto the sheet is fixed by the fixing device 32 and discharged.

In the above-described embodiment, after the operator presses the composite mode button 16c, the monochrome copy button 16a or the color
When the copy button 16b is pressed, the first toner image of the original image is formed on the TX belt 30 in steps S1 to S6.

Next, when the black-and-white copy button 16a or the color copy button 16b is depressed in a state where the original 21 is replaced and the composite mode is set, the toner image of the second original image is set to TX in steps S1 to S6. Formed on the belt 30.
Therefore, with the composite mode set, the black and white copy button
When the user presses the color copy button 16a or 16a, toner images of a plurality of document images are formed on the TX belt 30 in a superimposed manner.

After the operator replaces the original 21 and releases the composite mode button 16c, and presses the black and white copy button 16a or the color copy button 16b, the steps S1 to S6 are performed.
Then, the toner image of the last original image is formed on the TX belt 30 and the process proceeds from step S7 to step S8, where the composite toner image formed superimposed on the TX belt 30 is transferred to a sheet.

That is, before the paper is conveyed, it is determined whether or not the combining mode is set (step S7). Further, the composite mode cannot be released during the copying shown in steps S2 to S5.

Therefore, according to the above-described embodiment, when a plurality of original images are combined, the PC belt 26, the TX belt and the TX belt are overlapped while the respective toner images are formed on the TX belt 30 (steps S1 to S6). Continue to rotate 30 and PC belt 26 and T
The position of the X belt 30 is adjusted, and each toner image is
After being formed on the X belt 30 in an overlapping manner,
Since the composite toner image is transferred to paper before fixing the image,
The positioning accuracy of each image can be improved, and the synthesis time can be shortened.

FIG. 6 shows a second embodiment of the image forming apparatus according to the present invention.
FIG. 7 is an explanatory view showing a transfer medium, that is, a TX belt 40 in the embodiment, and FIG. 7 is a flowchart for explaining the operation of the CPU in the second embodiment. In the second embodiment, components other than the configuration of the TX belt 40 shown in FIG. 6 and the program of the CPU shown in FIG. 7 are the same as those of the first embodiment, so that the drawings and description thereof are omitted.

As shown in FIG. 6, the TX belt 40 is configured so that its length is about 300 mm longer than the maximum paper size (17 inches), and the CPU performs positioning in this non-image area. Similarly, a slit 40a (TX index) for position detection is formed in the TX belt 40, and the T
X index 40a and PC index of PC belt 26
26a is formed such that the rear end of the maximum image area on the TX belt 40 is located at the contact position B (FIG. 3) between the PC belt 26 and the TX belt 40 at the time of detection.

In step S11 shown in FIG.
The mode set by 16 is processed and set in the RAM 13, and copying is started in the following step S12. Next, in step S13, the PC motor 17a and the TX motor 18
After the rotation of a is started and the PC belt 26 and the TX belt 40 reach predetermined end positions in the image area, a toner image is formed on the PC belt 26 and the TX belt 40 (step S14).
In the following step S15, it is determined whether or not the combining mode is set in the RAM 13. If the combining mode is not set, the process proceeds to step S16, in which the motor for transporting the sheet is driven to drive. The toner image on the TX belt 40 is transferred onto paper. Therefore, the toner image transferred onto the sheet is fixed by the fixing device 32 and discharged.

On the other hand, if the combining mode is set in the RAM 13 in step S15, the process jumps to step S17 to determine whether or not the TX index 40a of the TX belt 40 has been detected. If the TX index 40a is not detected, this process is repeated, and the TX index 40a
Is detected, the process proceeds to step S18, where the PC motors 17a, T
The rotation of the X motor 18a is stopped, and the flow returns to step S11 to process the next original.

In the above-described embodiment, similarly to the first embodiment, after the respective toner images are formed so as to be superimposed on the TX belt 40, that is, before the respective toner images are fixed, the composite toner image is formed. The PC belt 26 and the TX belt 40 are stopped after the rear end of the maximum image area on the TX belt 40 reaches the contact position B between the PC belt 26 and the TX belt 40. This is done in the non-image area on 40. Therefore, it is possible to prevent displacement of each image at the time of stopping.

Further, before and after the start of copying of the second and subsequent sheets, the PC belt 26 and the TX belt 40 are in contact with each other in the non-image area on the TX belt 40 until the predetermined leading end position of the image area is reached. Since the next toner image is aligned in this non-image area, the PC belt 26 and the TX belt
The speed non-uniformity at the time of 40 rise can be absorbed. Therefore, the positioning accuracy of each image can be improved.

FIG. 8 shows a third embodiment of the image forming apparatus according to the present invention.
The operation of the transfer medium, that is, the operation of the TX belt 40 in the embodiment will be described. The configuration of the TX belt 40 shown in FIG. 8, that is, the width and length are the same as those of the second embodiment.

FIG. 9 is a flowchart for explaining the operation of the CPU in the third embodiment. C shown in FIG.
The components other than the PU program are the same as those in the first and second embodiments, and therefore will not be described.

Hereinafter, the flowchart of FIG. 9 will be described.

First, the mode set by the operation unit 16 is set.
The data is processed and set in the RAM 13 (step n1), and copying is started (step n2). Next, the PC motor 17
a, Start rotation of the TX motor 18a (step n)
3) After the PC belt 26 and the TX belt 40 reach a predetermined leading end position in the image area, the toner image
It is created on the belt 40 (step n4). Subsequently, it is determined whether or not the combination mode is set in the RAM 13 (step n5). If the combination mode is not set, the motor for transporting the paper is driven to activate the TX belt 40. The upper toner image is transferred onto paper (step n6). Therefore, the toner image transferred onto the sheet is fixed by the fixing device 32 and discharged.

On the other hand, in step n5, the synthesis mode
If the code is set in the RAM 13, the TX belt 40
It is determined whether or not the TX index 40a is detected (step n7). When the TX index 40a is not detected, this process is repeated. When the TX index 40a is detected, the rotation of the PC motor 17a and the TX motor 18a is stopped (step n7), and the TX encoder 18b shown in FIG.
Is set in the RAM 13, that is, the value n from the start of the stop to the completion of the stop.

Next, after the PC motor 17a and the TX motor 18a start reverse rotation (step n9), the count value n
Is decremented by 1 (step n10), and the count value n
It is determined whether or not has reached a predetermined slightly smaller value (for example, 20) (step n11). If the result of the determination is NO, the process returns to step n9 to return to the PC motor 17a and the TX motor 18a.
Is reversed, and if YES, the PC motors 17a, T
The reverse rotation of the X motor 18a is stopped, and the flow returns to step n1 to process the next original.

Therefore, in this embodiment, similarly to the second embodiment, the rear end of the maximum image area on the TX belt 40 is the PC belt.
After the contact point B between the PC belt 26 and the TX belt 40 is reached, the PC belt 26 and the TX belt 40 are stopped, so that this stop is performed in a non-image area on the TX belt 40,
It is possible to prevent displacement of each image at the time of stopping.
Also, unlike the second embodiment, before and after the start of copying of the second and subsequent sheets, and until the predetermined leading edge position of the image area is reached, the PC belt 26 and the TX belt 40 rotate in reverse during the previous copying. TX where PC belt 26 and TX belt 40 contact
A long non-image area on the belt 40 can be ensured, so that even if the rising speeds of the PC belt 26 and the TX belt 40 do not match, the positioning accuracy of each image can be further improved.

[0052]

[Effect of the Invention] The image forming apparatus according to claim 1, original image
And a photoreceptor for forming a plurality of toner images corresponding to the image forming area, and an image forming area and a non-image forming area. a transfer medium to synthesize the number of bets toner image, and a control means for controlling the facing movement of the transfer medium, control means for each of a plurality of bets toner image is superimposed and transferred onto the transfer medium,
The contact point between the photosensitive member and the transfer medium to stop the transfer medium so as to be located in a non-image forming region of the transfer medium, then the formation and transfer medium on the photoreceptor DOO Na <br/> over image When the contact point reaches the image forming area of the transfer medium at the time of the rise of the superimposed transfer, the distance required from the leading end of the image forming area of the transfer medium is obtained as described above, since the contact point moves the transfer medium is configured to align multiple bets toner image, the sheet after a plurality of bets toner image is synthesized are sequentially transferred to the transfer medium The transferred toner image is fixed collectively on the paper, so that the alignment accuracy of each image can be improved and the synthesizing time can be shortened. Within the image forming area In this case, it is possible to prevent an adverse effect on the toner image formed in the image forming area of the transfer medium due to the inconsistency in the moving speed between the photosensitive member and the transfer medium at the time of stopping, and furthermore, according to the image of the original, In order to match the moving speed between the photoconductor and the transfer medium when the contact point reaches the image forming area of the transfer medium at the time of forming the toner image on the photoconductor and superimposing transfer onto the transfer medium, The transfer speed of the transfer medium, the contact point, the image of the transfer medium
When forming an image up to the end of the non-image forming area on the tip side of the forming area
Image forming operation after moving in the direction opposite to the
The rise of the moving speed between the photoconductor and the transfer medium
Minimizing the length of the non-image forming area
And can reduce the size of the device,
It is possible to improve the alignment accuracy between the toner image on the transfer medium and the toner image on the photoconductor at the time of transfer synthesis of the toner image on the photoconductor onto the transfer medium.

[0053]

[0054]

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric system of a full-color copying machine provided with an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a plan view showing a detailed configuration of an operation unit in FIG. 1;

FIG. 3 is a front sectional view showing a mechanism system of the full-color copying machine shown in FIGS. 1 and 2;

FIG. 4 is an explanatory view showing the TX belt and the PC belt of FIG. 3;

FIG. 5 is a flowchart showing the operation of the CPU when synthesizing a plurality of document images.

FIG. 6 is an explanatory view showing a TX belt in a second embodiment of the image forming apparatus according to the present invention.

FIG. 7 is a flowchart for explaining the operation of the CPU in the second embodiment.

FIG. 8 is an explanatory view showing the operation of a TX belt in a third embodiment of the image forming apparatus according to the present invention.

FIG. 9 is a flowchart for explaining the operation of the CPU in the third embodiment.

FIG. 10 is a front sectional view showing a conventional black-and-white copying machine.

[Explanation of symbols]

 11 CPU (Central Processing Unit) 16c Synthetic mode button 17a, 18a Motor 17b, 18b Encoder 17c, 18c Sensor 21 Original 26 PC belt 30, 40 TX belt 26a, 30a, 40a Slit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/00 303 G03G 21/00 370-540

Claims (1)

(57) [Claims] A photosensitive member to form a plurality of toner images as claimed in claim 1] corresponding to the image of the document, the face moves the toner image formed on the has an image forming area and the non-image forming area on the photoreceptor a transfer medium to synthesize preparative Na <br/> over images of the multiple superimposed transferred to the image forming region, and a control means for controlling the facing movement of said transfer medium, wherein, each time the plurality of bets toner image is superimposed and transferred to the transfer medium, the contact point of the photosensitive member and said transfer medium to stop the transfer medium so as to be located in a non-image forming region of the transfer medium , then the front at the time of rising of the forming and superimposing transfer onto the transfer medium on the photoreceptor of Quito toner image, and the photosensitive member when the contact point reaches the image formation region of the transfer medium To match the transfer speed with the transfer medium, As required distance is obtained from the tip of the image forming region of the transfer medium, the transfer medium the contact points
To the non-image forming area end of the tip side of the image forming region of the body, the moving direction during image formation is configured to move the transfer medium in the reverse direction align the bets toner image of the multiple An image forming apparatus comprising: