DE4323630A1 - Correction method and correction device for a photocopier - Google Patents

Abstract

A photocopier comprises a DX-code reader (6) for reading a DX-code or an identification code of a negative film, a film scanner (2) for measuring the density information of the negative film, and an exposure unit (4) for exposing the copier paper. The exposure unit (4) is controlled on the basis of the exposure information which is derived from the conversion information which is selected with regard to the identification and density information. A test copy is made of the reference film for correction purposes and the conversion information of a plurality of types of film is collected on the basis of the density of the test copy and of the density of the reference film measured by the film scanner (2). <IMAGE>

Description

The invention relates to a correction method and a Correction device for a photocopier.

With a photocopier, it is necessary to change the order Correct formation information to make changes to a Film density meter and a copy paper exposure device to take into account.

Usually a variety of correction film Types made for all combinations from copy film and copy paper, which are necessary for the apparatus Question come. These correction film types are used for this purpose applies several types of transformation information correct.

In the prior art, however, the larger the number of film types used for copying, so much the more Time and work required to correct through respectively. For photocopiers, therefore, a ver simple correction procedure required.

The present invention has been made under consideration made of the prior art shown above and has the task of a correction procedure and a device  for speeding up and saving work on corrections available for photocopiers even if many film types are set for copying sets are.

According to the invention, this object is achieved by a correction method for use in a photocopier apparatus which comprises the following method steps:
Determining the identification information with film identification means, the identification information indicating one type among a plurality of film types loaded for copying; Measuring the density density of the film loaded for copying with film density measuring means; and controlling copy paper exposure means with control means based on the identification information and the density of density; the control means being operable to select, based on the identification information, the reshaping information corresponding to the film loaded for copying from a plurality of types of reshaping information which have been created to derive the exposure information from the density density information to check the copy paper exposure means, and which have been prepared in accordance with a variety of combinations of film and copy paper to be copied, that they derive the exposure information from the reshaping information and the density density selected according to the film to be copied, and that they control the copy paper exposure means based on the exposure information derived.

This method is characterized in that the Control means are so operable that they the Kopierpa pier exposure agent for test copying a loaded control correction film and the forming information tion for the large number of film types to be copied rig based on the density density information a test copy and the density density information the correction measured by the film density measuring means filmes.

When correcting the photocopier by Ver of the present invention measure the film thickness means the density density information of a cor rectifying film and the control means based on the exposure information the copy paper exposure medium to perform a test copy. Based on the density density information of the measured Test copy and the density density information provided by the film density measuring means will be obtained Corrected several types of transformation information leads that for several combinations of to be copied Film and copy paper were made. This means, that the invention takes into account the fact that Än changes in the film density measuring means and copy paper illuminants affect all film types in the same way rivers. Consequently, a correction procedure is made with the help of a correction film, to cover several refor Types of information related to multiple combinations from the film to be copied and the photocopier to correct the copy paper in question.  

With this correction procedure for the photocopier a correction procedure is carried out at once with With the help of a correction film to several transformations formation types in relation to several combinations film to be copied and at the photocopier in Correct the coming copy paper. The Cor rectification procedure is accelerated and work at the cor correction procedure for the photocopier saved, even if a variety of film types for copying to be used.

The control means can be operated such that they determine the exposure information for test copying men from the measured by the film density measuring means Density density information and from the reference Umfor development information worked out for the correction film is to get the exposure information from the Schwär to obtain density information.

The control means can test copy based on the exposure information required for the Correction film is worked out.

In addition, the control means can change the reference Correct the information of the correction film based on the density density of the test copy and the density density information provided by the Film density measuring means are measured, and then the different types of transformation information of the copying film based on the relatio nalen information, the relationships between the Refe marginal transformation information of the correction film and the  Reshaping information of the different to be copied Shows film types.

The correction film can be formed by a Film that according to the type one of the different copying film types. This ensures one Advantage compared to the case of making the Correction film from a special film type because it it is not necessary to speci? ell for correction purposes.

According to another aspect of the invention becomes a correction device for a photocopier Provided that includes: film identification means for determining the identification information tion, which is a type among a variety of for copy indicates the type of film loaded; Film density measuring means to measure the density density information of the to Copying inserted film; and control means for Control copy paper exposure means based on the identification information and the density density information; the control means so operable are based on the identification information mation the transformation information according to the Copy inserted film select from a variety of transformation information types that are used to derive the Exposure information from the density of density information was made to copy paper control and in accordance with a variety of combinations of what is to be copied Film and copy paper were made to the Be clearing information from the reshaping information  forward according to what is loaded for copying Film and the density density information selected and based around the copy paper exposure means to control on the derived exposure information.

This apparatus is characterized in that the Density information means are provided to the color or density of density due to the copy paper light-sensitive copy and measure that the Control means can be operated so that they copy the Control paper exposure to a loaded one Test copy the correction film and around the reshaping formation of the multitude of film types to be copied correct based on the density information of a Test copy measured by the copy density measuring means and based on the density information of the Cor rectifying film measured by the film density measuring means will.

With this correction device, the control means auto matically those in the above correction procedure included functions. This will be a further saving of work achieved for the corrective ture procedure, since the control means automatically ver perform various processes for correction.

The above and other tasks, features and Advantages of the invention will be described in more detail hand a preferred embodiment of the Erfin as shown in the accompanying drawings is.  

Fig. 1 shows a plan view of a photocopier according to the present invention;

Fig. 2 is an accompanying drawing for the measurement processing;

Fig. 3 is an accompanying drawing for spectral sensitivity correction; and

Fig. 4 is a sketch of a correction film.

A color photocopier is used accordingly of the present invention described with reference on the drawings.

Fig. 1 shows a plan view of the color photocopier. A length portion of a developed negative film 1 to be copied moves from left to right in Fig. 1. The negative film 1 then passes through a DX code reader 6 , which functions as a film identification device, a negative film scanner 2 , which functions as a film density meter, a storage area 3, and a copy paper exposure unit 4 , which functions as a copy paper exposure device.

An exposure controller 5 , which functions as a control device, selects the shaping information which is used for the negative film 1 and the copy paper 46 , as described below, based on the identification information of the negative film 1 determined by the DX code reader 6 . The exposure controller 5 checks the copier paper exposure unit 4 based on the forming information and the information measured by the film scanner 2 about the density of blackening. To the extent that this application speaks of density or density of blackening, it should also be understood to mean any color density.

The color photocopier has a normal print mode for printing the negative film 1 and a correction mode for setting the device, which will be described later. The respective operating mode is selected by a keyboard 51 for entering commands and data.

The DX code reader 6 reads a DX code which is an identification code recorded on the film. As mentioned above, the DX code reader 6 transmits the identification information to the exposure controller 5 .

The negative film scanner 2 includes a combination of image line sensors 21 and color filters 22 to divide each frame of the negative film 1 into a plurality of areas and the light that has been emitted from a reading light source 23 and has passed through the negative film 1 to split into the three primary colors red, green and blue, which are measured for each area. The number of areas into which an individual image is divided is between 100 and 1000 depending on the number of segments of the image line sensor 21 , the segment width in the running direction of the negative film 1 and the throughput rate of the negative film 1 . The measurements obtained from the film scanner 2 are forwarded to the exposure controller 5 as density density information. The exposure controller 5 converts the measurements forwarded as density information from the film scanner 2 into density values by obtaining logarithms of the measurements. These blackening density values are then considered as blackening density values of the negative film 1 .

The storage area 3 is located where the negative film 1 - instead of being fed to the copy paper exposure unit 4 - is available until the film scanner 2 has completed the density measurement of all or some of the individual images of the negative film. The negative film 1 is kept there in a loop form. This memory area 3 can be omitted if a sufficient track length for the negative film 1 is provided between the film scanner 2 and the exposure unit 4 .

The exposure unit 4 includes an exposure source 41 for illuminating the individual images to be printed out of the negative film 1 and a lens 42 for projecting images recorded on the negative film 1 onto the copy paper 46 . The color balance of the exposure, that is, the exposure values of the respective colors, is adjusted by the exposure controller 5 , which processes the blackening density information of the negative film 1 measured by the film scanner 2 and controls an optical filter 43 accordingly. The exposure unit 4 also has a light diffuser 44 for producing a uniform color mixture of the light passing through the optical filter 43 and an aperture 45 for blocking the optical path after completion of the exposure.

Based on the identification information obtained from the DX code reader 6 and the density density information obtained from the negative film scanner 2 , the exposure controller 5 controls the copy paper exposure unit 4 according to the following procedure.

When controlling the optical filter 43 of the exposure unit 4 according to the density density information of the film scanner 2 , it is necessary to take the information to be printed from the negative film 1 . This information extraction process is described first.

After the conversion of the photometric values received by the film scanner 2 into density values, the green density of the three primary color density data is treated as a reference value for classifying the data of each measured area by a green density value. This is done specifically by dividing the green density into appropriate intervals and grouping the data of each measured area for each section. Average values of the green density data, the red density data and the blue density data are then obtained for each group. These average values are shown in FIG. 2. In Fig. 2, the green density is divided into groups corresponding to an interval of 0.15. The horizontal axis represents green density, while the vertical axis represents red and blue density. The plotted points are approximations to matching curves, whereby a red characteristic curve 71 and a blue characteristic curve 72 are obtained. Figure 2 also shows a green characteristic curve 73 plotted for comparison purposes.

The points on the two characteristic curves 71 and 72 belonging to the same green density can be regarded as the so-called Evans principle, which is obtained by photographing a gray object. These represent the characteristic information for the negative film 1 , which is not influenced by the photographed object. Thus, with respect to the two characteristic curves 71 and 72 in Fig. 2, the red density "r" and the blue density "b" with respect to the average green density "g" in a frame to be printed represent the densities that allow it to label this single image as corresponding to gray.

The density values thus obtained cannot be used as they are when calculating the exposure, since the spectral sensitivity in the film scanner 2 does not usually coincide with the overall spectral sensitivity, including the spectral sensitivity of the copy paper in the exposure unit 4 . It is therefore necessary to make a correction in order to bring the spectral sensitivity in the film scanner 2 into agreement with the spectral sensitivity in the exposure unit 4 .

A basic concept for correcting the deviations in the spectral sensitivity is described with reference to FIG. 3.

In Fig. 3, the two curves R and S show wavelength dependency or transmission spectra of the color information of the negative film 1 for different exposures. The wavelength range P shows a maximum value of the spectral sensitivity of the copy paper. The wavelength range N shows a maximum value of the spectral sensitivity of the negative film scanner 2 . As can be seen in FIG. 3, the sensitivity differences between the copy paper and the film scanner 2 , that is to say Δx and Δy, can be corrected in relation to different exposures of the negative film 1 with the coefficients Δx / Δy.

The three colors are used in the current correction influences, and mutual overlaps occurring complicate the process.

A sequence of the current correction is shown below described.

The correction is carried out based on a reshaping printout which provides reshaping information for reshaping differences in the density values obtained from the photometric values obtained from the film scanner 2 into differences in the density values of the copy paper. This transformation expression can be represented in matrix notation ( 1 ).

In expression ( 1 ), Δr, Δg and Δb represent differences in the density values for the three primary colors obtained from the photometric values of the film scanner 2 , ΔR, ΔG and B are differences in the density density values of the copy paper and a11 to a33 are constants. The constants a11 to a33 can be obtained by producing a correction negative film 8 which contains four individual images - as shown in FIG. 4 - for example a gray individual image 81 , an individual image 82 with a red density increased by a certain amount , a frame 83 with green density increased by the certain amount and a frame 84 with blue density increased by the certain amount, by test printing the single frames under the same exposure conditions and by measuring the density of density. From this, Δr, Δg, Δb are derived from the density differences between the gray individual image and the individual images with the respective colors enlarged by the specific amount. At closing, ΔR, ΔG and BB are derived from the density differences between the test print of the gray image and the test print of the images with the respective colors enlarged by the specific amount. Finally, the equations are solved by solving Expression ( 1 ).

The constants a11 to a33 in expression (1) are variable for different combinations of negative film 1 and copy paper 46 , since the negative film 1 and the copy paper 46 each have different spectral sensitivities. Consequently, a different deformation expression must be prepared for each different combination of negative film 1 and Kopierpa pier 46 .

The different forming expression for each under different combination of negative film 1 and Kopierpa pier 46 is not stored as it is in the exposure controller 5 , but is saved after going through a certain processing. A forming printout prepared for the combination of correction film 8 and copy paper 46 is saved intact as a reference forming printout in the exposure controller 5 . Forming expressions corresponding to other combinations of negative film 1 and copy paper 46 and a Relatio nalausdruck, which provides information related to the above-mentioned reference forming expression, are stored in the exposure controller 5 .

For example, suppose that the transform expression (1) represents the reference transformation expression and that the Expression (2) corresponds to a transformation expression a certain combination of negative film and Copy paper represents, would be a specific case such a relational expression plays a matrix as shown in expression (3), the ratio nisse between the corresponding matrix elements in expressions (1) and (2).

In the present application of the conversion terms, the DX code reader 6 detects the film type, whereas the type of the copy paper 46 is entered via the command and data entry keyboard 51 . The transformation expression to be used (2) is derived from the matrix expression (3) according to this combination of negative film 1 and copy paper 46 and according to the reference transformation expression (1). As long as this reshaping expression is expressed in differences, the constant terms that form the basis for the differences can be obtained by printing the correction film 8 on the copy paper 46 and measuring the density of density of the two.

The reference conversion printout can also not be based on the combination of a specially provided correction film 8 with the copy paper 46 , but rather on a combination that was selected from several combinations of the negative film 1 with the copy paper 46 that are suitable for this device.

After the correction of the density values, which allow the printing of individual images and which are considered to be equivalent to gray, was carried out with the aid of the above-described forming printout, the exposures are derived on the basis of the corrected density values. The corrected density values express the density of the negative film 1 in the color density appearing on the copy paper. Since the individual image of the negative film 1 to be printed has a density corresponding to gray, the exposures are determined for the copying process, so that the density of the copy paper 46 on which the image is printed is also gray.

A procedure for setting the exposures is made described below.

Exposures are determined by using a relationship between exposure differences for print preparation and density density differences of the copy paper 46 .

The relationship can be determined by the following matrix expression (4) are expressed:

In expression (4), ΔDr, ΔDg and ΔDb density differences on the copy paper 46 , ΔEr, ΔEg and ΔEb represent the density differences on the copy paper 46 causing exposure differences and c11 to c33 constants. The constants c11 to c33 can be performed by performing test prints with four Exposures are obtained, for example, exposure for a gray print, exposure for red increased by a predetermined amount, exposure for green enhanced with the predetermined amount, and exposure for blue enhanced with the predetermined amount, and measuring the respective you That is, ΔEr, ΔEg and ΔEb are obtained from differences between the exposure for the gray print and the exposure for the colors enhanced by the specified amount. Thereafter, ΔDr, ΔDg and ΔDb are derived from the density differences between the gray test print and test print of the exposures for the respective colors intensified by the specified amount. Finally, the simultaneous equations decomposing expression (4) are resolved.

The constants a11 to a33 in the expression (4) are variable according to various combinations of the negative film 1 with the copy paper 46 . Consequently, a different forming expression must be prepared for each different combination of the negative film 1 with the copy paper 46 , as was the case with the forming expression (1).

Likewise, each different forming printout for each different combination of the negative film 1 with the copy paper 46 is not stored as it is in the exposure controller 5 , but is stored after it has been subjected to a certain processing. A for the combination of the correction film with the copy paper 46 prepared conversion printout is stored as it is as a reference conversion printout in the exposure controller 5 . Forming expressions corresponding to other combinations of the negative film 1 with the copy paper 46 and a relational expression which produces information relating to the above-mentioned reference forming expressions are stored in the exposure controller 5 .

Assume, for example, that the transformation expression (4) represents the reference transformation expression and that the Expression (5) corresponds to a transformation expression a certain combination of the negative film with the Copy paper, would be a specific case play one for such a relational expression Matrix as in expression (6), the relationships between the corresponding constant matrix elements in the Expressions (4) and (5).

In the present application of the conversion terms, the DX code reader 6 determines the film type, whereas the type of the copy paper 46 is entered via the command and data entry keyboard 51 . The forming expression (5) is derived from the forming expression (6) in accordance with the present combination of negative film 1 and copy paper 46 and in accordance with the reference forming expression (4). The differences between the gray density values and the density values transmitted by the deformation expressions (1) or (2) are replaced for ΔDr, ΔDg and ΔDb in order to obtain exposure differences ΔEr, ΔEg and ΔEb. While this transformation term is expressed in exposure differences, the constant terms that form the basis for the differences can be obtained using the exposure with which the gray print is made.

The reference conversion printout can also not be based on the combination of the specially provided correction film 8 with the copy paper 46 , but rather on one of the combinations of the negative film 1 with the copy paper 46 that come into question with this device. In practice, it is advantageous to use the same combination as for expression (1) for the reference transformation expression.

The exposure controller 5 selects - as already mentioned - relational information in printouts (3) and (6) based on the film identification information obtained from the DX code reader and derives the shaping information from the in accordance with the combination of the film to be copied with the copy paper relatio nal information and the reference transformation information in expressions (1) and (4). In other words, the exposure controller 5 selects the conversion information based on the film identification information of the DX code reader 6 in accordance with the combination of the film to be copied with the copy paper. Based on the deformation information and the measurement or density information of the film scanner 2 , the exposure controller 5 defines the exposures which represent the exposure information for the production of a print. In addition, the exposure controller 5 controls the copy paper exposure unit 4 based on the exposure information.

A device correction is described below.

After the device is switched from the editing mode to the correction mode in response to a command from the keyboard 51 , the exposure controller 5 causes the film scanner 2 to measure the blackening density of the correction film 8 . Then, the correction film is test-copied onto the copy paper 46 to obtain a new reference conversion printout according to the expressions (1) or (4) according to the method described above. A copy made by the test copying or a print is measured by a density density meter 52 , which is connected to the exposure controller 5 to work as a copy density meter. The density meter 52 can of course also be used in general in pressure-density measurement without being limited to correction functions only. The exposure condition of the correction film 8 during test copying is based on the density of the gray frame 81 in the correction film 8 , which is measured by the film scanner 2 . As described above, an exposure can be derived from the measured density of blackening or an exposure determined as suitable for the gray single image 81 can also be used.

Expressions corresponding to expressions (1) and (4) are provided for all combinations of the negative film 1 with the copy paper 46 that are possible for the device. When making corrections, it is not necessary to get new transformation terms for all of these combinations. A new reshaping expression can be obtained for making corrections as described above. Thereupon new forming expressions for all combinations of the negative film 1 with the copy paper 46 are obtained from the new reference forming expression and the relational expression of the already obtained reference forming expression and the respective forming expressions.

As described above, the correction mode is also controlled by the exposure controller 5 . This happens for the reason that the respective components of the color copier are also used in the correction mode. This means that a correction device is installed as a whole part of the color copying machine.

In the embodiment shown above, all transformation terms are corrected with the corrected reference transformation expression and relational expression. Instead, all conversion terms can be corrected by adding an exposure correction amount derived from the correction film 8 and copy paper to the corresponding conversion terms.

The four-frame negative is used as the correction film 8 as shown in FIG. 3. The Schwärzungsdich th of each frame can be adapted to divided areas of a frame. An image or images of other colors with increased density can be added.

Claims (19)

1. Correction procedure for use with a photo copier consisting of the following steps:
Determining the identification information with film identification means, the identification information indicating one type among a plurality of film types loaded for copying;
Measuring the density information of the film loaded for copying with film density measuring means; and
Controlling copy paper exposure means with control means based on the identification information and the density information;
the control means are to be operated in such a way
that, based on the identification information, they select the reshaping information corresponding to the film loaded for copying from a plurality of reshaping information types which have been created to derive the exposure information from said density information to control the copy paper exposure means and which are in accordance with a variety of combinations the film and copy paper to be copied have been created,
that they derive the exposure information from the conversion information selected in accordance with the film to be copied and the density information, and
that they control the copy paper exposure means based on the derived exposure information; and
said control means are to be operated in such a way
that they control the copy paper exposure means to test copy an inserted correction film, and
that they correct the reshaping information of the aforementioned number of film types to be copied based on the density information of a test copy and the density information of the correction film measured by the film density measuring means. 2. Correction method according to claim 1, wherein the Control means are to be operated such that they are a Re Fermentation information of the correction film basie based on the density information of the test copy and the density information measured by the film density measuring means Correct tion and then several reshaping information types of films to be copied based on correct a reference information that the ratio nisse between the reference transformation information of the Correction film and the reshaping information of the ge named variety of film types to be copied. 3. Correction method according to claim 1, wherein the Kor rectal film is formed from a film type, the iden table with one of the variety of film to be copied is types. 4. The correction method according to claim 1, wherein the Control means are to be operated such that they are the loading clearing information for test copying from the the film density measuring means measured density information  determine and from the reference forming information, which was created for the correction film to the Be clearing information from the density of density information tion. 5. The correction method according to claim 4, wherein the Control means are to be operated such that they the Re Fermentation information of the correction film basie based on the density information of the test copy and the density information measured by the film density measuring means Correct tion and then several forming information types of films to be copied based on the Correct reference information that the relationships between the correction's reference transformation information turfilmes and the reshaping information of the multitude of film types to be copied. 6. Correction method according to claim 4, wherein the Kor rectal film is formed from a film type, the iden table with one of the variety of film to be copied is types. 7. The correction method according to claim 1, wherein the Control means are to be operated in such a way that they Test copying based on the exposure information that was created for the correction film. 8. The correction method according to claim 7, wherein the cor rectal film is formed from a film type, the iden table with one of the many to be copied Film types is.   9. The correction method according to claim 7, wherein the Control means are to be operated such that they the Re Fermentation information of the correction film basie based on the density information of the test copy and the density information measured by the film density measuring means Correct tion and then several forming information types of films to be copied based on the Correct reference information that the relationships between the correction's reference transformation information turfilmes and the transformation information of several shows copying film types. 10. Correction method according to claim 9, wherein the Kor rectal film is formed from a film type, the iden table with one of the multitude to be copied Film types is. 11. The correction method according to claim 1, wherein the film identification means are formed by a DX code reader ( 6 ) for reading a DX code which represents an identification code and on which the film ( 1 ) is to be copied and which contains the identification forwarding information of the film to be copied ( 1 ) to the control means. 12. The correction method according to claim 1, wherein the film density measuring means are formed from a negative film scanner ( 2 ), which includes a combination of image line sensors ( 21 ) and color filters ( 22 ). 13. The correction method according to claim 1, wherein the copier paper exposure means includes an exposure source ( 41 ) for illuminating a single image of the film to be copied, a lens ( 42 ) for projecting an image recorded on the film to be copied ( 1 ) onto the copy paper ( 46 ) , an optical fil ter (43), which is controllable by the control means, a light diffuser (44) to produce a uniform color mixing of the by said optical rule filter (43) that has passed the light and an aperture (45) for blocking the optical path by Execution of the exposure. 14. Correction device for a photocopier consisting of:
Film identification means for obtaining the identification information indicating one of a plurality of film types loaded for copying; Film density measuring means for measuring the density information of the film loaded for copying;
Copy paper exposure means for exposing the copy paper;
Control means for controlling the copy paper exposure means based on the identification information and the density information; and
Copy density measuring means for measuring the density of an exposed print;
the control means being operable in such a way
that, based on the identification information, selects the reshaping information corresponding to the film loaded for copying from a plurality of reshaping information types that is designed to derive the exposure information from the density information to control the copy paper exposure means and in accordance with a variety of combinations of film to be copied and copy paper are created,
that they derive the exposure information from the conversion information selected in accordance with the film to be copied and the density information, and
that they control the copy paper exposure means based on the derived exposure information,
that they control the copy paper exposure means to test copy an inserted correction film, and
that the reshaping information of multiple copies correct the film types based on the density information of a test copy and the density information of the correction film measured by the film density measuring means. 15. A correction device according to claim 14, wherein the film identification means are formed by a DX code reader ( 6 ) for reading a DX code which represents an identification code and is recorded on the film ( 1 ) to be copied and which Passes identification information of the film to be copied ( 1 ) to the control means. 16. The correction device according to claim 14, wherein the film density measuring means are formed from a negative film scanner ( 2 ), which includes a combination of image line sensors ( 21 ) and color filters ( 22 ). 17. A correction device according to claim 14, wherein the copy paper exposure means include an exposure source ( 41 ) for illuminating a single image of the film to be copied ( 1 ), a lens ( 42 ) for projecting an image recorded on the film to be copied ( 1 ) onto the copy paper ( 46 ), an optical filter ( 43 ) which can be controlled by the control means, a light diffuser ( 44 ) for producing a uniform color mixture of the light flowing through said optical filter ( 43 ) and an aperture ( 45 ) for blocking the optical Path after the exposure is performed. 18. A correction device according to claim 14, wherein the density measuring means measure the density of blackening.