JP2006243257A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus with which images to be formed in rear surface recording can be appropriately selected when front recording on a recording material is performed. <P>SOLUTION: The image forming apparatus performs image formation on a recording material surface Ps to be supplied from a recording material supply section 1, then inverts the front and the rear of the material, places the material on the recording material supply section 1 and performs image formation on the recording material rear surface Pr. The apparatus is equipped with prescribed pattern forming means 2 for forming a prescribed pattern capable of prescribing rear surface information of the recording material P and its image direction in a part of the recording material surface Ps concomitantly in surface image formation, a reading means 3 for reading the information of the prescribed pattern prior to the image formation to the recording material rear surface Pr, a memory means 4 for storing the image data on at least the rear surface Pr, and an image control means 5 for performing image selection of the image to be formed on the rear surface Pr, and the selection of the image direction based on the information in the prescribed pattern read by the reading means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly, to an image forming apparatus of a type in which after recording on one side of a recording material, Regarding improvement.

Conventionally, for example, in a printer using an electrophotographic method, as a double-sided recording method without a paper reversing mechanism such as a reversing unit, once a single-sided recording is performed on the paper surface, the paper is fed again to the paper feeding unit. There is known a method of artificially turning over and resetting and recording on the back side of the paper.
In such a double-sided recording method, for example, when creating a page such as a manual, an identification mark or an alignment mark is given at the time of recording on the front side of the paper, and at the time of recording on the back side, the back side is set in the paper feeding unit. When aligning the paper transport direction with the alignment mark, the image orientation of the front and back sides of the paper to be printed on both sides is matched, or the back side image corresponding to the front image is selected with the identification mark. The system which performs is shown (for example, refer patent document 1).

Japanese Patent Laying-Open No. 2003-39769 (Embodiment of the Invention, FIG. 4)

  However, in such a system, if the paper conveyance direction at the time of back side recording differs only by applying an identification mark to the paper on which front side recording has been completed, the images on the front side and the back side of the image are uneven as they are. There is concern to become. In addition, in order to align the paper conveyance direction in advance, the method of visually checking and resetting the alignment mark is particularly useful when various images are output by a network printer or the like. This is troublesome to check each of the images and realign the recorded alignment mark as a reference.

  The present invention has been made in order to solve the above technical problem, and when performing front surface recording on a recording material, it is possible to appropriately select an image to be formed during back surface recording. An image forming apparatus is provided.

That is, according to the present invention, as shown in FIG. 1, after image formation is performed on the recording material surface Ps supplied from the recording material supply unit 1, the recording material P on which the surface recording has been performed is reversed and the recording material is again printed. In the image forming apparatus that is placed on the supply unit 1 and forms an image on the recording material back surface Pr, the back surface image information of the recording material P and its image are recorded on a part of the recording material surface Ps accompanying the surface image formation. Specific pattern forming means 2 for forming a specific pattern whose direction can be specified, reading means 3 for reading information on the specific pattern before image formation on the recording material back surface Pr, and storage for storing at least image data of the back surface Pr Based on the information of the specific pattern read by the means 4 and the reading means 3, the image selection of the image to be formed on the back surface Pr and the selection of the image direction are performed from the image data stored in the storage means 4. It is characterized in further comprising a image control unit 5.
In the figure, reference numeral 6 denotes an image forming portion capable of forming an image on the recording material P. For example, the specific pattern forming means 2 may be provided in a part thereof.

In such technical means, the image forming apparatus of the present invention is not particularly limited to a monochrome type or a color type, and the image forming system includes electrophotography, electrostatic recording, and an ink jet system.
Further, “accompanying surface image formation” includes not only an aspect in which a specific pattern is formed at the same time as the surface image formation, but also an aspect in which the specific pattern is applied at a time different from that at the time of forming the surface image separately. Means. That is, the image recording on the recording material surface Ps may be performed by, for example, forming the specific pattern and the image in two steps.

The reading means 3 according to the present invention may be any means that reads a specific pattern, and may be any system such as optical or magnetic. However, as a typical aspect, the optical reading system is simpler than the reading means 3. From the viewpoint of The storage unit 4 may be provided at any location in the image forming apparatus. For example, the storage unit 4 may be included in the control unit in the image forming unit 6.
Furthermore, the selection of the image and the selection of the image direction performed by the image control means 5 means that the image formed on the back surface Pr and the orientation of the image are adapted to the image formed on the front surface Ps, for example. Note that the image control unit 5 may be included in, for example, the control unit in the image forming unit 6.

In particular, the specific pattern in the present invention is not particularly limited, and may be a pattern that can be recognized by human eyes or may be configured by a person that cannot be recognized.
The specific pattern is preferably composed of a dot pattern that is unrecognizable or difficult for the human eye. In this case, the image on the recording material surface Ps can be easily distinguished from the specific pattern. The visibility of the image can also be improved.
Further, it is preferable that the specific pattern is formed near both the front end portion and the rear end portion of the recording material surface Ps in the recording material conveyance direction. By providing in the vicinity of the end portion, when the image is formed on the back surface Pr, the reading of the specific pattern by the reading unit 3 is performed quickly, and the image forming speed of the image forming unit 6 can be increased.
Furthermore, it is preferable that the specific pattern is formed simultaneously with the image formation on the surface Ps. In this case, for example, the specific pattern and the image formation on the recording material surface Ps are divided into two times and recorded. It is possible to prevent erroneous recognition of the relationship between the specified pattern, the back Pr image information, and the image direction.

  In addition, the image control unit 5 according to the present invention performs an image formation on the back surface Pr when the reading unit 3 recognizes the specific pattern, and stops the image formation or issues a warning when the specific pattern is not recognized. It is preferable to provide a processing unit. In this way, it is possible to notify that image formation is completed, for example, depending on the presence or absence of a specific pattern, and it is also possible to notify when the recording material P is set upside down by mistake. Become.

  Further, the surface Ps of the recording material P in the present invention is sealed with a sealing paper, a specific pattern is formed on the recording material surface Ps before sealing, and the image is sealed at the time of image formation on the recording material back surface Pr. It is also possible to provide an image forming apparatus capable of performing a sealing process with a sealing paper after reading a specific pattern on the front recording material surface Ps.

According to the present invention, there is provided an image forming apparatus of a type in which after one side recording on a recording material is performed, the recording material surface is artificially turned over again and recorded on the back surface. Is formed on a part of the recording material, and a specific pattern capable of specifying the back side image information and the image direction of the recording material is formed. Since the image and the appropriate direction of the image are obtained, it is not necessary to pay attention to the point of aligning to the direction of the recording material on which the image has been formed on the front surface,
It is not easy to worry about the order and directionality (image orientation) of recording materials.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 2 shows Embodiment 1 of an image forming apparatus to which the present invention is applied.
In the figure, the image forming apparatus according to the present embodiment constitutes a color printer, and a paper feed cassette 11 for supplying paper as a recording material can be pulled out to a paper feed unit 10 below the image forming apparatus. The image forming unit 20 for forming a full-color image of four colors of yellow (Y color), magenta (M color), cyan (C color) and black (K color) is provided above the paper supply unit 10, A reading unit 40 capable of reading image information on a sheet is provided between the sheet feeding unit 10 and the image forming unit 20.

In the present embodiment, in the vicinity of the paper discharge position of the paper feed cassette 11 in the paper feed unit 10,
A sheet feeding mechanism 12 for feeding sheets one by one from the sheet feeding cassette 11 is provided. In the sheet feeding mechanism 12, the sheet fed from the sheet feeding cassette 11 by the pickup roll 12a is fed to the feed roll 12b and the retard roll 12c. As a result, only the uppermost sheet is conveyed downstream.

The image forming unit 20 is installed on the downstream side of the image forming unit 30 that can form four full-color images on the paper, and is formed on the paper by the image forming unit 30. A fixing device 26 for fixing the toner image is provided.
The fixing device 26 in the present embodiment includes, for example, a heating roll 26a and a pressure roll 26b. However, the fixing apparatus 26 is not limited thereto, and may be an induction heating system or the like.
Further, in the present embodiment, a discharge roll 27 that discharges paper in the vicinity of the housing opening of the image forming unit 20 is provided on the downstream side of the fixing device 26, and the fixed paper is produced by the discharge roll 27. The image unit 20 is discharged to a storage tray 20a provided at the upper part of the housing.

  Further, in this image forming unit 20, a sheet conveying belt 22 that conveys a sheet to the image forming unit 30 is stretched around two stretching rolls 23 and 24 and is circulated and conveyed. Furthermore, a charging device 25 that allows the sheet to be attracted to the sheet conveying belt 22 is provided as a backup roll at a position facing the stretching roll 23 with the sheet conveying belt 22 interposed therebetween. A predetermined bias is applied when the sheet is conveyed, so that the sheet can be attracted to the sheet conveying belt 22 side.

The image forming unit 30 includes a toner cartridge 31 (31a to 31d) capable of forming toner images of four colors, and a photosensitive member that is disposed opposite to the housing opening of the toner cartridge 31 and carries toner images of each color. A laser exposure device (ROS: Raster Output Scanner) 36 for forming a latent image on the body 32 and a toner image formed on the photoreceptor 32 that is disposed opposite to the photoreceptor 32 outside the toner cartridge 31 and formed on the photoreceptor 32. The transfer roller 35 is configured to transfer to a sheet held on the sheet conveyance belt 22.
Further, in each toner cartridge 31 (31a to 31d), a charging roll 33 for charging the photoconductor 32 and a development for visualizing the photoconductor 32 on which the electrostatic latent image is formed with each toner. A roll 34 and the like are disposed.

The ROS 36 in the present embodiment intends to expose the four-color photoconductors 32 with one ROS 36. The ROS 36 includes a plurality of polygon mirrors, reflection mirrors, and the like so that the laser light is branched in four directions. It is like that.
Therefore, four-color images by the four-color image forming unit 30 in the image forming unit 20 can be performed by one exposure control, the exposure conditions are stabilized, and the four colors are more easily synchronized.

Further, the image forming unit 20 according to the present embodiment is provided with a manual feed tray 29 that enables manual feeding in addition to the paper conveyance path from the paper supply unit 10 side, and a conveyance roll 28 near the exit of the manual tray 29. Thus, the paper set on the manual feed tray 29 is conveyed.
Therefore, in the image forming unit 20, there are a paper conveyance path from the paper supply unit 10 and a paper conveyance path from the manual feed tray 29, and both of the conveyance paths are paper sheet positioning restrictions on the upstream side of the charging device 25. It extends to the registration roll 21 to be conveyed at the same time.

On the other hand, the reading unit 40 regulates the positioning of the paper transported from the paper feeding unit 10, the registration roll 42 transported downstream, and the image information (specifically, the paper whose positioning is regulated downstream of the registration roll 42. In particular, there is provided a reading sensor 41 configured to read, for example, specific pattern information).
The reading sensor 41 is disposed at a position where the image forming unit 30 in the image forming unit 20 reads information on the surface opposite to the surface on which the toner image is formed on the sheet.

In the configuration as described above, the sheet conveyance system in the present embodiment is configured such that the sheet fed from the sheet feeding cassette 11 by the sheet feeding mechanism 12 one by one is positioned and regulated by the registration roll 42 in the reading unit 40, and then the reading sensor. 41 is led into the image forming unit 20.
The sheet transported into the image forming unit 20 is positioned and transported by the registration roll 21, sucked onto the sheet transport belt 22 by the charging device 25, transported as it is on the sheet transport belt 22, and the image forming unit 30. The toner images inside are sequentially transferred onto the paper.
The sheet on which the toner images are multiplex-transferred is peeled off from the sheet transport belt 22 by a peeling means (not shown) provided in the vicinity of the tension roll 24, fixed by the fixing device 26, and discharged from the discharge roll 27 to the storage tray 20a. Discharged to the top.

Next, an image control system using a specific pattern which is a feature point of the present case will be described with reference to FIG.
This figure is a block diagram showing an image control system using a specific pattern in the present embodiment, and shows input / output to / from the control device 50 as the image control system.
The control device 50 includes, for example, a CPU, a ROM, a RAM, and the like, and based on information of a specific pattern read by the page information storage unit 51 and the reading sensor 41 that store image data from an external device or the like as page information. An image reading unit for reading out and outputting image data necessary for image formation from the page information storage unit 51 based on information from the formed image determining unit 52 and an image to be formed and a direction for determining the direction of the image. It consists of part 53 and the like.

FIG. 4 shows an example of the layout of the specific pattern in this embodiment.
In this figure, in the present embodiment, areas of specific patterns are provided at both the leading and trailing edges in the paper transport direction, and the specific patterns are printed on both. For this reason, when the information of the specific pattern is read by the reading sensor 41, it can be determined at the leading end portion of the conveyed paper, so that the corresponding back side image can be specified at an early stage.

In addition, as shown in FIG. 5, the specific pattern in the present embodiment is configured by a dot pattern using a yellow color arranged at the front end portion X and the rear end portion Y on the surface of the paper, and the human eye Is not easily recognizable.
For example, page information to be formed on the back side of the paper in the α area, and the top and bottom information of the image formed on the paper surface in the β and γ areas (the orientation of the image) Is determined). At this time, by reversing the top and bottom information of the β region and the γ region, for example, when the paper leading end X is read by the reading sensor 41 (see FIG. 2), the top (upper) of the image formed on the surface is read. On the other hand, if the rear end Y of the sheet is read first by the reading sensor 41, it can be recognized as the ground (downward direction) of the image formed on the surface.
Note that the page information in the α area may be the number of pages of the image formed on the front side of the paper. In short, the number of pages to be formed on the back side of the paper and the direction of the image can be identified by a specific pattern. If it is.

Next, the operation of the color printer in the present embodiment will be described based on the control flow of FIGS. 6A and 6B and FIGS.
For example, when printing a so-called page object such as a manual, the flow for printing odd-numbered pages on one side (front surface) of the paper is as shown in FIG.
When printing is started, a specific pattern for specifying the back side image is printed on the odd page to be printed in the specific pattern area at the leading edge and the trailing edge of the paper at the same time as the odd page image printing ( Step S1). At this time, by providing the specific pattern at the leading edge and the trailing edge, for example, the leading edge information or trailing edge information of the odd-numbered page image can be written in both. When any one of the specific patterns is read by the reading sensor 41, the image information and the image direction of the back surface to be printed are specified.

Then, it is determined whether or not the printing of the odd pages has reached the originally required number of pages (step S2). When the requested number is reached, printing of odd pages is completed, and a display such as “return the output paper to the paper feed cassette 11” is displayed on the console panel, for example (step S3).
At this time, if the requested number has not been reached, the process returns to step S1, and printing of odd pages is repeated until the requested number is reached.

  Subsequently, after the odd-numbered page printing on the front side of the paper is reversed and reset in the paper feed cassette 11, the flow for printing on the back side of the paper is as shown in (b). When resetting the paper, it is desirable that all the paper should be set with the front and back sides aligned so that the back side of the paper is printed. For example, the top and bottom direction of the printed image remains uneven. It can be reset.

When printing is started, the reading sensor 41 reads the specific pattern printed on the paper surface (odd page) side (step S11). At this time, it is determined whether or not the paper to be conveyed has a specific pattern (step S12), and if the specific pattern is confirmed, then the information on the specific pattern indicates the paper conveyance direction (the top and bottom are reversed). Whether or not) (step S13).
Then, if it is determined that the top and bottom of the image on the paper surface is reversed, the top and bottom of the image corresponding to the odd page printed by the specific pattern information (the image of the even page) is reversed and output (step S14). On the other hand, if the top and bottom of the odd-numbered page image is not reversed by the information based on the specific pattern, the corresponding image (even-numbered page image) is output as it is.
Subsequently, even-numbered pages are printed based on the output image information (step S15).

The printing as described above is repeated to determine whether or not the predetermined number of sheets has been reached (step S16). If the requested number is not reached, the process returns to step S11 to repeat printing.
Further, in the present embodiment, if the specific pattern is not confirmed in step S12, printing is stopped or a warning is displayed (step S17). As an example in which the specific pattern is not confirmed, for example, when there is no image on the back side (even page) corresponding to the last page, the specific pattern is not provided on the odd page side, or the paper is set in the paper feed cassette 11. An example of a mistake (set to print on the front side of a sheet on which odd pages are printed) is assumed.

  As described above, in the present embodiment, for example, when performing double-sided printing of a page, etc., once printing is performed on one side, then the paper is reversed and reset, and this time printing on the opposite side of the paper is performed. In such a printer, it is not necessary to align the direction and order of the sheets at the time of resetting, and this troublesome operation is not necessary.

Next, as a modification of the present embodiment, an example in which the color printer of the present embodiment is used and sealing paper is used will be described.
FIG. 7 shows a schematic diagram when sealing paper is used, and shows an example of sealing a postcard, for example.
That is, a specific pattern is printed on the document to be sealed on one side (printing surface side) of the postcard and the leading and trailing edges of the document. At this time, if the document to be sealed is related to personal information, the address of each individual is listed as corresponding information.
Next, when single-sided printing is completed, the postcard is reversed and reset, and backside printing is performed. At this time, in order to seal the sealed document (document printed on the front surface), the sealing paper coated with paste in advance is set in another paper feeding unit (specifically, the manual feed tray 29 shown in FIG. 2), Address printing is performed on the back side of the sealed document in a state where the sealed document and the sealed paper overlap.

Thereafter, the fixing of the address printing by the fixing device (specifically, the fixing device 26 shown in FIG. 2) and the glue applied to the sealing paper are melted and pasted.
In this example, since image formation is performed with two sheets of sealed document and sealed paper, the image forming conditions may be changed as appropriate. In addition, as a sealing paper paste, for the purpose of melting and fixing by heat fixing, for example, a transparent toner having a melting point lower than that of a normal toner and not containing a color pigment can be applied in advance by a printer. It is. Further, since fixing is performed by overlapping two sheets of sealed document and sealing paper, it is better to raise the fixing temperature of the fixing device (specifically, the fixing device 26 shown in FIG. 2) slightly higher than usual.

Next, the state of paper conveyance in the system using such sealing paper will be described with reference to FIGS.
FIG. 8A shows a stage in which the paper to be printed on the paper feed cassette 11 (for example, a postcard in this example) is conveyed from the paper feed cassette 11 one sheet at a time by the winding mechanism 12.
FIG. 5B shows a stage where the sheet conveyed from the sheet feeding cassette 11 is regulated by the registration roll 21.
(C) shows a stage where a sealed document is formed on a sheet by the image forming unit 30 (in this stage, an unfixed toner image).
(D) shows a stage where the sealed document is fixed by the fixing device 26 and discharged from the discharge roll 27.
Thus, by repeating the steps of FIGS. 8A and 8B, a plurality of sealed documents having different specific patterns can be printed.

On the other hand, the reverse side printing of the paper on which the sealed document is printed and the sealing paper are fixed as shown in FIG.
FIG. 9A shows a stage in which the single-sided printed paper is reversed and reset in the paper feed cassette 11 and the sealing paper coated with paste around the manual feed tray 29 is set. .
(B) reads the specific pattern of the paper conveyed from the paper feeding cassette 11 by the paper feed mechanism 12 by the reading sensor 41 and also starts the conveyance of the sealing paper conveyed from the manual feed tray 29. A stage where two sheets are superimposed (positioning regulation) is shown.
(C) shows a stage in which an image such as a destination is formed by the image forming unit 30 in a state where two sealed documents and two sealed papers overlap each other.
In (d), the image formation is completed, and the image such as the address is fixed by the fixing device 26, and the glue of the sealing paper is also melted and pasted, and the paper on which the sealed document is printed and the sealing paper are fixed. The stage of being discharged by the discharge roll 27 is shown.

Next, the operation of the color printer when such a sealed document and sealed paper are used will be described with reference to the control flow of FIGS. 10 (a) and 10 (b) and FIGS.
For example, the flow for printing personal information as a sealed document on paper such as a postcard is as shown in FIG.
When printing is started, a specific pattern for specifying an address or the like as backside image information is printed on the front surface of the paper to be printed in a specific pattern area at the leading and trailing edges of the paper. (Step S21).

Then, it is determined whether or not the number of sealed documents printed on the paper has reached the initially required number of sheets (step S22). When the requested number is reached, printing is completed, and a display such as “return the output paper to the paper feed cassette 11” is displayed on the console panel, for example (step S23).
If the requested number has not been reached at this time, the process returns to step S21, and printing is repeated until the requested number is reached.

  Subsequently, the paper on which the sealed document has been printed on the front side of the paper is inverted and reset in the paper feed cassette 11, and then the address on the back side of the paper and the front side of the paper (the side on which the sealed document is printed) The flow for fixing the sealing paper is as shown in (b). At this time, when resetting, it is desirable that all the sheets should be set with the front and back sides aligned so that the back side of the sheet is printed. There is no problem.

When printing is started, the reading sensor 41 reads a specific pattern printed simultaneously with the sealed document on the front side of the paper (step S31). At this time, it is determined whether or not the sheet to be conveyed has a specific pattern (step S32), and if the specific pattern is confirmed, then whether or not the sheet is transported according to the specific pattern (whether the top and bottom are reversed). ) Is determined (step S33).
If it is determined that the top / bottom of the image on the paper surface is reversed, the top / bottom of the image corresponding to the sealed document printed by the information from the specific pattern (an image such as an address) is inverted and output (step S34). On the other hand, if the top and bottom of the image of the sealed document is not reversed by the information based on the specific pattern, the corresponding image (address, etc.) is output as it is.
Subsequently, based on the output image information, printing is performed on the back side of the paper, and sealing paper is simultaneously pasted by the fixing device 26 (step S35).

The printing as described above is repeated to determine whether or not the predetermined number of sheets has been reached (step S36). If the requested number is not reached, the process returns to step S31 to repeat printing.
Furthermore, in the present embodiment, if the specific pattern is not confirmed in step S32, printing is stopped or a warning is displayed (step S37).

  Thus, when the front and back sides of a sheet such as a sealed document are specified, an appropriate image can be easily printed by specifying the back side image information and the direction thereof.

Embodiment 2
FIG. 11 shows Embodiment 2 of an image forming apparatus to which the present invention is applied. Although this embodiment is configured in substantially the same manner as the color printer of the first embodiment, the image forming unit in the image forming unit of the first embodiment is compatible with four colors, but additional colors are possible. This embodiment is different from the first embodiment in that an image forming unit is provided. Components similar to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted here.

  In the present embodiment, the reading unit 40 is mounted on the paper feeding unit 10, and the four colors are arranged on the reading unit 40 instead of the image forming unit 20 of the first embodiment (see, for example, FIG. 2). An engine unit 20B having an image forming unit 30 and a fixing unit 20A having a monochrome image forming unit 60 and a fixing device 26 are mounted on the engine unit 20B.

The image forming unit 60 in the fixing unit 20 </ b> A according to the present embodiment is, for example, a toner cartridge 61 capable of forming a transparent toner image, and a toner image supported on the housing opening of the toner cartridge 61. A ROS 66 for forming a latent image on the photosensitive member 62; a transfer roll 65 which is disposed outside the toner cartridge 61 so as to face the photosensitive member 62 and transfers a toner image formed on the photosensitive member 62 onto a sheet; It consists of
Further, inside the toner cartridge 61, there are disposed a charging roll 63 for charging the photosensitive member 62, a developing roll 64 for visualizing the photosensitive member 62 on which the electrostatic latent image is formed with toner, and the like. .

As described above, in the present embodiment, in addition to the image forming unit 30 that forms four full-color images, the image forming unit 60 that forms transparent toner, for example, is further provided. It is possible to further expand variations such as increasing the glossiness of images.
The toner colors in the two image forming units 30 and 60 in the present embodiment are not particularly limited. For example, in the image forming unit 30 in the engine unit 20B, Y color, M color, and C color are used. The toner image of K color may be formed, and the image forming unit 60 on the fixing unit 20A side may be provided with a black color that is different in gloss from the K color on the engine unit 20B side.

In addition, if a low melting point toner is used as the transparent toner in the present embodiment, it is possible to perform printing similar to the sealing paper paste application described in the first embodiment.
Further, it is possible to form a specific pattern with a transparent toner mixed with a fluorescent agent, and to read the specific pattern by irradiating with ultraviolet rays. In this case, recognition by human eyes can be made more difficult. .

In the present exemplary embodiment, for example, the image forming unit 60 on the fixing unit 20A side may be configured to be K toner and may not include the engine unit 20B. In this case, the image forming unit 60 can function as a monochrome printer. Become. However, in this case, since the specific pattern also uses K color toner, for example, a dot pattern is confirmed from the human eye. At this time, if it is a very small pattern or the like as the specific pattern, there is no particular problem in practical use.
In this case, if the engine unit 20B is added to such a monochrome printer when it is determined that colorization is necessary, the investment cost can be optimized.

(A) (b) is explanatory drawing which shows the outline | summary of the image forming apparatus based on this invention. 1 is an explanatory diagram showing Embodiment 1 of an image forming apparatus to which the present invention is applied. FIG. 3 is a block diagram illustrating a pattern control unit according to the first embodiment. 5 is an explanatory diagram illustrating an outline of an image according to Embodiment 1. FIG. 4 is an explanatory diagram illustrating a specific pattern according to Embodiment 1. FIG. (A) (b) is explanatory drawing which shows the flow of Embodiment 1, (a) is a recording material surface, (b) shows the correspondence to a recording material back surface. FIG. 6 is an explanatory diagram illustrating an example in which sealing paper is used as a modification of the first embodiment. (A)-(d) is explanatory drawing which shows the conveyance condition of the recording material in the modification of Embodiment 1. FIG. (A)-(d) is explanatory drawing which shows the conveyance condition of the recording material and sealing paper in the modification of Embodiment 1. FIG. (A) (b) is explanatory drawing which shows the flow of Embodiment 1, (a) is a recording material surface, (b) shows the correspondence to a recording material back surface. FIG. 6 is an explanatory diagram illustrating an overview of an image forming apparatus according to a second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Recording material supply part, 2 ... Specific pattern formation means, 3 ... Reading means, 4 ... Memory | storage means, 5 ... Image control means, 6 ... Image formation part, P ... Recording material, Ps ... Surface (recording material surface), Pr ... Back side (back side of recording material)

Claims (6)

After image formation on the surface of the recording material supplied from the recording material supply unit, the front and back surfaces of the recording material on which surface recording has been performed are reversed and placed again on the recording material supply unit, and an image is formed on the back surface of the recording material In the forming device,
A specific pattern forming means for forming a specific pattern capable of specifying the back surface image information and the image direction of the recording material for a part of the recording material surface accompanying the front surface image formation;
Reading means for reading the information of the specific pattern before image formation on the recording material back surface;
Storage means for storing at least the back side image data;
And image control means for selecting an image to be formed on the back surface and selecting an image direction from the image data stored in the storage means based on the information of the specific pattern read by the reading means. Image forming apparatus. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the specific pattern is formed on both the vicinity of the front end portion and the rear end portion of the recording material surface in the recording material conveyance direction. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the specific pattern includes a dot pattern that is unrecognizable or difficult for human eyes. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the specific pattern is formed when an image is formed on a recording material surface. The image forming apparatus according to claim 1.
The image control unit includes an abnormality processing unit that performs image formation on the back side when the specific pattern is recognized by the reading unit, and stops image formation or issues a warning when the specific pattern is not recognized. Image forming apparatus. The image forming apparatus according to claim 1.
The surface of the recording material is sealed with a sealing paper, a specific pattern is formed on the surface of the recording material before sealing, and a specific pattern on the surface of the recording material before sealing is formed when an image is formed on the back surface of the recording material. An image forming apparatus which performs sealing processing with sealing paper after reading.

Images